Dr. Carvalho's work was supported by a research grant from the Office of Research on Women's Health and National Institute of Child Health and Human Development of the National Institutes of Health (5K12 HD043452). Dr Angst received supplies (On-Q PainBuster Post-Op Pain Relief System) and funds (for the biochemical assays) from I-Flow (Lake Forest, California).

1. Study Protocol
<ul>
	<li>Obtain Institutional Review Board approval and written informed consent.</li>
	<li>Select an appropriate surgical population for study conduct. This methodology has only been applied to cesarean delivery wounds but most surgical wounds would be appropriate.</li>
	<li>Consider inclusion and exclusion criteria for your study participation. Patients and procedures with high rates of surgical wound infection may not be appropriate.</li>
	<li>Standardize anesthesia and postoperative management for all patients to avoid potential confounders.</li>
</ul>
2. Nociceptive and Inflammatory Biochemical Mediator Collection
<ul>
	<li>Insert the ON-Q PainBuster with ON-Q SilverSoaker (I-Flow, Lake Forest, CA) into the subcutaneous layer just prior to wound closure (other tissue layers can be considered). The ON-Q PainBuster Pain Relief System continuously delivers normal saline at a rate of 2 ml/h. The carrier can be combined with or compared to drugs of interest such as a local anesthetic and non-steroidal anti-inflammatories.</li>
	<li>Incorporate a standard three-way stopcock into this system to allow aspiration of wound exudate at specified time points. The continuous infusion prevents the catheter from clotting and improves the reliability of the system to produce exudate samples. If aspiration of exudate is difficult (approximately 5% of cases), consider pushing gently above the wound, changing the subject's position (e.g., sitting the patient up or lying them flat), using a 0.5-1 ml normal saline flush or withdrawing the catheter 1-2 cm.</li>
	<li>At time points specified by the protocol (e.g., 1, 4, 6, 24, and 48 hr after cesarean delivery), aspirate and withdraw 1 ml of wound exudate. Transfer the exudate into a polyethylene cup containing 30 &mu;l of proteinase inhibitor. We have used Complete Proteinase Inhibitor (Roche Bioscience, Palo Alto, CA) for our purposes.</li>
	<li>At the same time intervals specified by the study protocol, collect 10 ml of blood. We have used a blood collection tube containing lithium heparin; at our institution this is a green-topped glass tube. Add an additional 300 &mu;l of proteinase inhibitor into the blood samples.</li>
	<li>Within 1 hr of collection, put samples on ice and centrifuge at 3,000 rpm for 10 min.</li>
	<li>Remove serum and wound supernate and place in a standard microcentrifuge tube and store at -20 &deg;C.</li>
</ul>
3. Assay Analysis
<ul>
	<li>Once all the study exudate and serum samples are collected and stored, thaw and analyze the samples at the same time.</li>
	<li>We have measured the cytokines and chemokines using a multiplex immunoassay. The multiplex immuno-assay technique allows us to assay numerous analytes from small (50 &mu;l) volume samples. The multiplex produce results comparable with those obtained with ELISA. We have used the 17-plex Bio-PlexTM system (BioRad, Hercules, CA) for our analysis. This assay is capable of measuring tumor necrosis factor &alpha; (TNF&alpha;), interferon &alpha; (INF&alpha;), interleukin 1&beta; (IL-1&beta;), interleukin 2 (IL-2), interleukin 4 (IL-4), interleukin 5 (IL-5), interleukin 6 (IL-6), interleukin 7 (IL-7), interleukin 8 (IL-8), interleukin (IL-10), interleukin 12 (IL-12), interleukin 13 (IL-13), interleukin 17 (IL-17), granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein 1 (MIP-1&beta;). Nerve growth factor was measured with NGF DY256 antibody by adding it to the 17-plex plate with the Bio-Plex amine coupling kit.</li>
	<li>To ensure good quality analysis, each measurement should be made in duplicate. Standard curves for each analyte are generated by using reference analytes supplied by the manufacturer (at concentrations of 0.20, 0.78, 3.13, 12.5, 50, 200, 800, 3,200 pg/ml plus a zero standard for the normal saline). Standard curves are included in each run and sample concentrations are calculated with Bio-Plex Manager software.</li>
	<li>Substance P and prostaglandin E2 were measured using highly sensitivity ELISA Kits. We have used Assay Designs, Inc. (Ann Arbor, Michigan) for this analysis. Perform the analysis in duplicate according to the manufacturer's specification.</li>
</ul>

<ol>
	<li>Carvalho, B., Clark, D. J., Angst, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Local+and+Systemic+Release+of+Cytokines,+Nerve+Growth+Factor,+Prostaglandin+E2,+and+Substance+P+in+Incisional+Wounds+and+Serum+Following+Cesarean+Delivery.">Local and Systemic Release of Cytokines, Nerve Growth Factor, Prostaglandin E2, and Substance P in Incisional Wounds and Serum Following Cesarean Delivery.</a> J. Pain. 9, 650-657 (2008).</li><li>Carvalho, B., Clark, D. J., Yeomans, D. C., Angst, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+subcutaneous+instillation+of+bupivacaine+compared+to+saline+reduces+interleukin+10+and+increases+substance+P+in+surgical+wounds+after+cesarean+delivery.">Continuous subcutaneous instillation of bupivacaine compared to saline reduces interleukin 10 and increases substance P in surgical wounds after cesarean delivery.</a> Anesth. Analg. 111, 1452-1459 (2010).</li><li>Verri, W. A., Cunha, T. M., Parada, C. A., Poole, S., Cunha, F. Q., Ferreira, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypernociceptive+role+of+cytokines+and+chemokines:+targets+for+analgesic+drug+development.">Hypernociceptive role of cytokines and chemokines: targets for analgesic drug development.</a> Pharmacol. Ther. 112, 116-138 (2006).</li><li>Watkins, L. R., Maier, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immune+regulation+of+central+nervous+system+functions:+from+sickness+responses+to+pathological+pain.">Immune regulation of central nervous system functions: from sickness responses to pathological pain.</a> J. Intern. Med. 257, 139-155 (2005).</li><li>Beilin, B., Bessler, H., Mayburd, E., Smirnov, G., Dekel, A., Yardeni, I., Shavit, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+preemptive+analgesia+on+pain+and+cytokine+production+in+the+postoperative+period.">Effects of preemptive analgesia on pain and cytokine production in the postoperative period.</a> Anesthesiology. 98, 151-155 (2003).</li><li>Wu, C. T., Jao, S. W., Borel, C. O., Yeh, C. C., Li, C. Y., Lu, C. H., Wong, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+epidural+clonidine+on+perioperative+cytokine+response,+postoperative+pain,+and+bowel+function+in+patients+undergoing+colorectal+surgery.">The effect of epidural clonidine on perioperative cytokine response, postoperative pain, and bowel function in patients undergoing colorectal surgery.</a> Anesth. Analg. 99, 502-509 (2004).</li><li>Buvanendran, A., Kroin, J. S., Berger, R. A., Hallab, N. J., Saha, C., Negrescu, C., Moric, M., Caicedo, M. S., Tuman, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Upregulation+of+prostaglandin+E2+and+interleukins+in+the+central+nervous+system+and+peripheral+tissue+during+and+after+surgery+in+humans.">Upregulation of prostaglandin E2 and interleukins in the central nervous system and peripheral tissue during and after surgery in humans.</a> Anesthesiology. 104, 403-410 (2006).</li><li>Kristiansson, M., Soop, M., Sundqvist, K. G., Soop, A., Suontaka, A. M., Blomback, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Local+vs.+systemic+immune+and+haemostatic+response+to+hip+arthroplasty.">Local vs. systemic immune and haemostatic response to hip arthroplasty.</a> Eur. J. Anaesthesiol. 15, 260-270 (1998).</li><li>Liu, S. S., Richman, J. M., Thirlby, R. C., Wu, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficacy+of+continuous+wound+catheters+delivering+local+anesthetic+for+postoperative+analgesia:+a+quantitative+and+qualitative+systematic+review+of+randomized+controlled+trials.">Efficacy of continuous wound catheters delivering local anesthetic for postoperative analgesia: a quantitative and qualitative systematic review of randomized controlled trials.</a> J. Am. Coll. Surg. 203, 914-932 (2006).</li><li>Eriksson, A. S., Sinclair, R., Cassuto, J., Thomsen, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+lidocaine+on+leukocyte+function+in+the+surgical+wound.">Influence of lidocaine on leukocyte function in the surgical wound.</a> Anesthesiology. 77, 74-78 (1992).</li><li>Clark, J. D., Shi, X., Li, X., Qiao, Y., Liang, D., Angst, M. S., Yeomans, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphine+reduces+local+cytokine+expression+and+neutrophil+infiltration+after+incision.">Morphine reduces local cytokine expression and neutrophil infiltration after incision.</a> Mol. Pain. 3, 28 (2007).</li><li>Webb, S. T., Ghosh, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intra-articular+bupivacaine:+potentially+chondrotoxic.">Intra-articular bupivacaine: potentially chondrotoxic.</a> Br. J. Anaesth. 102, 439-441 (2009).</li><li>Scott, N. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wound+infiltration+for+surgery.">Wound infiltration for surgery.</a> Anaesthesia. 65, 67 (2010).</li></ol>

No conflicts of interest declared.

This methodology outlined above has been found to be sensitive enough to detect biochemical inflammatory and nociceptive mediators in wound exudate. Sampling at various time-points has also allowed us to observe changes of these mediators over time.1,2 We are not aware of any other human surgical wound assay that can serially measure the release profile of inflammatory and nociceptive mediators in surgical wound exudate. Results from our methodology of wound exudate collection from the surgical incision site is different from studies utilizing drains from the hip joint,7,8 which suggests that subcutaneous wound mediator release may be different from intraarticular or other body cavities biochemical mediator release. Additionally, results obtained in drains may be confounded by blood loss into the wound, and therefore they may not accurately reflect local biochemical mediator release.
The poor correlation between wound and serum levels demonstrates the importance of determining site-specific release when studying surgical wounds. Local changes may not be reflected systemically due to many factors including differential systemic and local production in response to surgical trauma and stress. Although we have chosen to measure a particular selection of pro- and anti-inflammatory cytokines and chemokines as well as NGF, SP and PG-E2 from cesarean delivery wound exudate,1,2 this methodology can be applied to other surgical models and many other biochemical mediators.
Surgical wound local anesthetic instillation is a commonly used technique for improving postoperative pain.9 Applying the methodology, we have been able to demonstrate that local anesthetic instillation into surgical wounds does affect wound biochemistry.2 A decrease in IL-10 and increase in substance P in wound exudates with bupivacaine instillation suggests a disruption of anti-inflammatory modulation. Peripherally administered local anesthetics may thereby affect the inflammatory processes,10,11 which may partially account for local anesthetic-induced chondrolysis in joints after surgery.12
ON-Q PainBuster Pain Relief System is a US Food and Drug Administration (FDA) approved device since 1998 that is used for the delivery of local anesthetics to the surgical wound site to reduce pain following surgery. Continuous wound instillation utilizing this and other catheters has not been associated with increased wound infection.9,13 ON-Q PainBuster with ON-Q SilverSoaker is designed to infuse drugs and not to repeatedly sample wound exudate. Although we have had no wound infections with this technique, we stress an aseptic technique while sampling wound exudate from this system. Our proposed modification to facilitate sampling should be reserved for research purposes and not for routine clinical use. We also recommend that the duration the catheter remains in-situ be limited to 48-72 hours.
This surgical site bioassay technique provides a good model to understand the relationship between inflammatory and nociceptive biochemical mediators in postoperative pain. We will use the methodology in future studies to investigate effects of locally administered non-steroidal anti-inflammatory drugs and opioids. The technique may also lend itself to investigations examining wound healing, excessive surgical scarring and wound infection.

After a surgical incision, resident and migrating inflammatory cells release pro- and anti-inflammatory cytokines, prostanoids, neuropeptides and chemokines that are important for initiating and maintaining pain.3,4 The ability to collect site-specific biochemical markers is critical to determine the relationship between levels in serum and surgical wound, understand the complex relationship between mediator release and surgical pain, and to be able to evaluate the effect of both systemic and peripheral drug administration on surgical wound biochemistry. Studies have focused on systemic measurements of biochemical mediators and have not considered site-specific release.5,6 Serum measurements of cytokines and chemokines may not be reflective of local surgical wound biochemical events and only indicate a global systemic response to surgical injury. This article provides a detailed and unique visual description of this methodology that was first referenced in 2008 in the Journal of Pain.1 The aim of this JoVE article is to provide a unique and visually enhanced description of the methods.

collecting and measuring wound exudate biochemical mediators in surgical wounds

We describe a methodology by which we are able to collect and measure biochemical inflammatory and nociceptive mediators at the surgical wound site. Collecting site-specific biochemical markers is important to understand the relationship between levels in serum and surgical wound, determine any associations between mediator release, pain, analgesic use and other outcomes of interest, and evaluate the effect of systemic and peripheral drug administration on surgical wound biochemistry. This methodology has been applied to healthy women undergoing elective cesarean delivery with spinal anesthesia. We have measured wound exudate and serum mediators at the same time intervals as patient's pain scores and analgesics consumption for up to 48 hours post-cesarean delivery. Using this methodology we have been able to detect various biochemical mediators including nerve growth factor (NGF), prostaglandin E2 (PG-E2) substance P, IL-1&#x03B2;, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, TNF&alpha;, INF&#x03B3;, G-CSF, GM-CSF, MCP-1 and MIP-1&#x03B2;. Studies applying this human surgical wound bioassay have found no correlations between wound and serum cytokine concentrations or their time-release profile (J Pain. 2008; 9(7):650-7).1 We also documented the utility of the technique to identify drug-mediated changes in wound cytokine content (Anesth Analg 2010; 111:1452-9).2

Using this methodology we have been able to detect all biochemical mediators outlined above with the exception of IL-5 in wound exudate and plasma.1,2 Some additional cytokines were not detected in plasma (IL-4, IL-17, TNF&alpha;, INF&gamma;, GM-CSF).1 The time course of measured cytokines and chemokines in reported studies were consistent, reaching a plateau within the first few hours that was sustained for the 24 hour observation period..1,2 However, NGF increased steadily over the 24-hours collection period, whereas PGE2 peaked within 1 hour and then steadily decreased.1 Particularly noteworthy results are markedly decreased levels of IL-10 and increased levels of substance P in wounds instilled with the local anesthetic bupivacaine, compatible with an overall pro-inflammatory effect of the drug (Figure 1).2 In a different study we demonstrated that analgesic consumption after cesarean delivery surgery was negatively correlated with wound exudate IL-6, IL-1 &beta;, and G-CSF concentrations (Figure 2).1
<img alt="Figure 1" fo:content-width="3in" fo:src="/files/ftp_upload/50133/50133fig1highres.jpg" src="/files/ftp_upload/50133/50133fig1.jpg" /> 
Figure 1. Interleukin-10 (IL-10) and substance P wound exudate levels levels (pg/ml) measured at 1, 3, 5, 7, and 24 hours post-cesarean delivery. The normal saline group is indicated in gray diamonds, and the bupivacaine group is shown with black squares. *=Significantly different between groups (P &lt; 0.005).
<img alt="Figure 2" src="/files/ftp_upload/50133/50133fig2.jpg" /> 
Figure 2. Correlation between interleukin-6 (pg/ml) and morphine consumption in the first 24 hr after cesarean delivery.

Watch this Scientific Journal Video about Collecting And Measuring Wound Exudate Biochemical Mediators In Surgical Wounds at JoVE.com

Collecting And Measuring Wound Exudate Biochemical Mediators In Surgical Wounds

This article provides a detailed and visual description of a methodology for collecting and measuring biochemical inflammatory and nociceptive mediators at the surgical wound site following cesarean delivery. This human bioassay has been used to determine correlations between wound and serum cytokine concentrations and drug-mediated changes in wound cytokines, chemokines and neuropetides.

We describe a methodology by which we are able to collect and measure biochemical inflammatory and nociceptive mediators at the surgical wound site. ...

collecting-measuring-wound-exudate-biochemical-mediators-surgical

Nanyang Technological University

Research

JoVE Journal

Medicine

11.9K Views.  Stanford University School of Medicine. This article provides a detailed and visual description of a methodology for collecting and measuring biochemical inflammatory and nociceptive mediators at the surgical wound site following cesarean delivery. This human bioassay has been used to determine correlations between wound and serum cytokine concentrations and drug-mediated changes in wound cytokines, chemokines and neuropetides.

Video: Collecting And Measuring Wound Exudate Biochemical Mediators In Surgical Wounds

Collecting and Measuring Nociceptive and Inflammatory Mediators in Surgical Wounds 

We describe a methodology by which we are able to collect and measure inflammatory and nociceptive biochemical mediators at the surgical wound site. Collecting site-specific biochemical markers allows us to evaluate the relationship between surgical wound and serum levels; determine any associations between mediator release, pain and analgesic consumption; and evaluate the effect of systemic and peripheral drug administration on surgical wound biochemistry.
This methodology has been applied to healthy women undergoing elective cesarean delivery with spinal anesthesia. Wound exudate and serum mediators, in conjunction with pain scores and analgesics consumption were measured at 1, 6, 24, and 48 hours post-cesarean delivery. Biochemical mediators that were detected included IL-1&beta;, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, TNF&alpha;, INF&gamma;, G-CSF, GM-CSF, MCP-1 and MIP-1&beta;, nerve growth factor (NGF), prostaglandin E2 (PG-E2) and substance P. We found no correlations between wound and serum cytokines concentrations or time-release profiles (J Pain. 2008 Jul 9(7):650-7). This article describes and demonstrates the feasibility of collecting and assaying nociceptive and inflammatory mediators in surgical wounds at specific time points. The lack of significant correlations between serum and wound levels shows the importance of determining site-specific release if surgical wounds and localized pathologies are to be studied.

Collecting and Measuring Nociceptive and Inflammatory Mediators in Surgical Wounds

A technique to collect and measure surgical wound biochemical mediators at specific time points.

We describe a methodology by which we are able to collect and measure inflammatory and nociceptive biochemical mediators at the surgical wound site. ...

Biology

Murine Excisional Wound Healing Model and Histological Morphometric Wound Analysis

The murine excisional wound model has been used extensively to study each of the sequentially overlapping phases of wound healing: inflammation, proliferation and remodeling. Murine wounds have a histologically well-defined and easily recognizable wound bed over which these different phases of the healing process are measurable. Within the field, it is common to use an arbitrarily defined &#8220;middle&#8221; of the wound for histological analyses. However, wounds are a three-dimensional entity and often not histologically symmetrical, supporting the need for a well-defined and robust method of quantification to detect morphometric defects with a small effect size. In this protocol, we describe the procedure for creating bilateral, full-thickness excisional wounds in mice as well as a detailed instruction on how to measure morphometric parameters using an image processing program on select serial sections. The two-dimension measurements of wound length, epidermal length, epidermal area, and wound area are used in combination with the known distance between sections to extrapolate the three-dimension epidermal area covering the wound, overall wound area, epidermal volume and wound volume. Although this detailed histological analysis is more time and resource consuming than conventional analyses, its rigor increases the likelihood of detecting novel phenotypes in an inherently complex wound healing process.

This protocol describes how to generate bilateral, full-thickness excisional wounds in mice and how to subsequently monitor, harvest, and prepare the wounds for morphometric analysis. Included is an in-depth description of how to use serial histological sections to define, precisely quantify and detect morphometric defects.

The murine excisional wound model has been used extensively to study each of the sequentially overlapping phases of wound healing: inflammation, ...

Developmental Biology

Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels

This protocol describes noninvasive sampling of undisturbed upper airway mucosal lining fluid. It also details the extraction procedure used prior to the analysis of immune mediators in fluid eluates for the study of the airway topical immune signature, without the need for stimulation procedures (often used by other techniques). The mucosal lining fluid is sampled on a strip of filter paper placed at the anterior part of the inferior turbinate and left for 2 min of absorption. Analytes are eluted from the filter papers, and the extracted protein-based eluates are analyzed by an electrochemiluminescence-based immunoassay, allowing for the high-sensitivity quantification of low- and high-level analytes in the same sample. We measured the in vivo levels of 20 preselected immune mediators related to specific immune signaling pathways in the upper airway mucosa, but the technique is not limited to that specific panel or sampling site. The technique was first implemented in 7-year-old children from the Copenhagen Prospective Studies on Asthma in Childhood2000 (COPSAC2000) cohort with allergic rhinitis. It was thereafter used in the longitudinal COPSAC2010 birth cohort, sampled at 1 month, 2 years, and 6 years of age and at instances of acute respiratory symptoms. We successfully obtained and analyzed samples from 620 (89%) of 700 1-month-old children; a few samples were below the assay detection limit (reported as the median (Inter-Quartile Range (IQR)). The number of samples below the detection limit (i.e.&#160;from 0 to the set point for the lower limit of detection) for each mediator was 29 (7.25 - 119.5). This technique enables the quantification of the in vivo airway mucosal immune profile from birth, can be applied longitudinally, and can be applied to studies on the effect of genetics and early-life environmental exposures, pathophysiology, endotyping, and monitoring of respiratory diseases, and development and evaluation of novel therapeutics.

Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels

This protocol describes a noninvasive technique for the sampling of undisturbed mucosal lining fluid from the upper airways. It can be used to perform the quantification of in vivo levels of protein mediators, such as cytokines and chemokines, in subjects of all ages.

This protocol describes noninvasive sampling of undisturbed upper airway mucosal lining fluid. It also details the extraction procedure used prior to the ...

Immunology and Infection

Come to the Light Side: In Vivo Monitoring of Pseudomonas aeruginosa Biofilm Infections in Chronic Wounds in a Diabetic Hairless Murine Model

The presence of bacteria as structured biofilms in chronic wounds, especially in diabetic patients, is thought to prevent wound healing and resolution. Chronic mouse wounds models have been used to understand the underlying interactions between the microorganisms and the host. The models developed to date rely on the use of haired animals and terminal collection of wound tissue for determination of viable bacteria. While significant insight has been gained with these models, this experimental procedure requires a large number of animals and sampling is time consuming. We have developed a novel murine model that incorporates several optimal innovations to evaluate biofilm progression in chronic wounds: a) it utilizes hairless mice, eliminating the need for hair removal; b) applies pre-formed biofilms to the wounds allowing for the immediate evaluation of persistence and effect of these communities on host; c) monitors biofilm progression by quantifying light production by a genetically engineered bioluminescent strain of Pseudomonas aeruginosa, allowing real-time monitoring of the infection thus reducing the number of animals required per study. In this model, a single full-depth wound is produced on the back of STZ-induced diabetic hairless mice and inoculated with biofilms of the P. aeruginosa bioluminescent strain Xen 41. Light output from the wounds is recorded daily in an in vivo imaging system, allowing for in vivo and in situ rapid biofilm visualization and localization of biofilm bacteria within the wounds. This novel method is flexible as it can be used to study other microorganisms, including genetically engineered species and multi-species biofilms, and may be of special value in testing anti-biofilm strategies including antimicrobial occlusive dressings.

Come to the Light Side: In Vivo Monitoring of Pseudomonas aeruginosa Biofilm Infections in Chronic Wounds in a Diabetic Hairless Murine Model

Here we describe a novel diabetic murine model utilizing hairless mice for real-time, non-invasive, monitoring of biofilm wound infections of bioluminescent Pseudomonas aeruginosa. This method can be adapted to evaluate infection of other bacterial species and genetically modified microorganisms, including multi-species biofilms, and test the efficacy of antibiofilm strategies.

The presence of bacteria as structured biofilms in chronic wounds, especially in diabetic patients, is thought to prevent wound healing and resolution. ...

Assessment of Acute Wound Healing using the Dorsal Subcutaneous Polyvinyl Alcohol Sponge Implantation and Excisional Tail Skin Wound Models.

Wound healing is a complex process that requires the orderly progression of inflammation, granulation tissue formation, fibrosis, and resolution. Murine models provide valuable mechanistic insight into these processes; however, no single model fully addresses all aspects of the wound healing response. Instead, it is ideal to use multiple models to address the different aspects of wound healing. Here, two different methods that address diverse aspects of the wound healing response are described. In the first model, polyvinyl alcohol sponges are subcutaneously implanted along the mouse dorsum. Following sponge retrieval, cells can be isolated by mechanical disruption, and fluids can be extracted by centrifugation, thus allowing for a detailed characterization of cellular and cytokine responses in the acute wound environment. A limitation of this model is the inability to assess the rate of wound closure. For this, a tail skin excision model is utilized. In this model, a 10 mm x 3 mm rectangular piece of tail skin is excised along the dorsal surface, near the base of the tail. This model can be easily photographed for planimetric analysis to determine healing rates and can be excised for histological analysis. Both described methods can be utilized in genetically altered mouse strains, or in conjunction with models of comorbid conditions, such as diabetes, aging, or secondary infection, in order to elucidate wound healing mechanisms.

Here, two murine wound healing models are described, one designed to assess cellular and cytokine wound healing responses and the other to quantify the rate of wound closure. These methods can be used with complex disease models such as diabetes to determine mechanisms of various aspects of poor wound healing.

Wound healing is a complex process that requires the orderly progression of inflammation, granulation tissue formation, fibrosis, and resolution. Murine ...

Digital Planimetry for Assessing Wound Closure Kinetics in a Mouse Model

Chronic wounds, due to their high prevalence, are a serious global health concern. Effective therapeutic strategies can significantly accelerate healing, thereby reducing the risk of complications and alleviating the economic burden on healthcare systems. Although numerous experimental studies have investigated wound healing, most rely on qualitative observations or quantitative direct measurements. The objective of this study was to standardize an indirect wound measurement method using digital planimetry, incorporating digital scaling and segmentation. This approach addresses the lack of detailed, step-by-step methodologies for accurate wound assessment. A photodocumentation booth was designed and constructed, and computer-assisted digital planimetry tools were employed to minimize variability in measurements of the wound area, perimeter, and the distance from the wound center to its edges. A circular traumatic wound (5 mm in diameter) was created on the dorsal midline at the shoulder blade level of male CD1 mice (n = 4, 10 weeks old, 30-35 g). Wound evolution was photodocumented for 14 days using the custom-designed photo booth, which controlled lighting conditions, focal distance, and subject positioning. Scaling and wound measurements were performed using segmentation in ImageJ software, and statistical analysis was conducted using statistical analysis software. The kinetics of wound closure showed a slight increase in wound size and perimeter between day 0 and day 2, followed by a gradual decrease until complete closure by day 14. The photodocumentation booth and computer-assisted digital planimetry enabled quantitative measurements with minimal variability. In conclusion, these tools provide a reliable and reproducible method for evaluating wound closure kinetics in pre-clinical models.

Wounds represent a global health challenge. This study developed a standardized photo booth utilizing digital planimetry to minimize wound measurement variability. Monitoring wounds in mice over 14 days revealed an initial increase in wound area and perimeter, followed by gradual closure. This methodology may aid in evaluating wound closure kinetics in pre-clinical models.

Chronic wounds, due to their high prevalence, are a serious global health concern. Effective therapeutic strategies can significantly accelerate healing, ...

Bioengineering

Laser Capture Microdissection on Surgical Tissues to Identify Aberrant Gene Expression in Impaired Wound Healing in Type 2 Diabetes

The global prevalence Type 2 diabetes mellitus (T2DM) is escalating at a rapid rate. Patients with T2DM suffer from a multitude of complications and one of these is impaired wound healing. This can lead to the development of non-healing sores or foot ulcers and ultimately to amputation. In healthy individuals, wound healing follows a controlled and overlapping sequence of events encompassing inflammation, proliferation, and remodelling. In T2DM, one or more of these steps becomes dysfunctional. Current models to study impaired wound healing in T2DM include in vitro scratch wound assays, skin equivalents, or animal models to examine molecular mechanisms underpinning wound healing and/or potential therapeutic options. However, these do not fully recapitulate the complex wound healing process in T2DM patients, and ex vivo human skin tests are problematic due to the ethics of taking punch biopsies from patients where it is known they will heal poorly. Here, a technique is described whereby expression profiles of the specific cells involved in the (dys)functional wound healing response in T2DM patients can be examined using surplus tissue discarded following amputation or elective cosmetic surgery. In this protocol samples of donated skin are collected, wounded, cultured ex vivo in the air liquid interface, fixed at different time points and sectioned. Specific cell types involved in wound healing (e.g., epidermal keratinocytes, dermal fibroblasts (papillary and reticular), the vasculature) are isolated using laser capture microdissection and differences in gene expression analyzed by sequencing or microarray, with genes of interest further validated by qPCR. This protocol can be used to identify inherent differences in gene expression between both poorly healing and intact skin, in patients with or without diabetes, using tissue ordinarily discarded following surgery. It will yield greater understanding of the molecular mechanisms contributing to T2DM chronic wounds and lower limb loss.

This technique provides a guide to inflicting ex vivo wounds, performing laser capture microdissection and quantifying changes in gene expression related to poor wound healing processes in diabetes using clinically relevant human tissue.

The global prevalence Type 2 diabetes mellitus (T2DM) is escalating at a rapid rate. Patients with T2DM suffer from a multitude of complications and one ...

Monitoring Neutrophil Recruitment Dynamics and Bacterial Burden at the Infection Site in a Murine Model

Source: Anderson, L. S., et al. <a href="https://app.jove.com/v/59015">A Mouse Model to Assess Innate Immune Response to Staphylococcus aureus Infection.</a> J. Vis. Exp. (2019).
This video demonstrates in vivo imaging to study the neutrophil recruitment dynamics at an infection site in an immunocompromised, transgenic mouse with GFP-expressing neutrophils. It involves injecting luminescent bacteria to cause an infection. This leads to neutrophil recruitment to the infection site, whose tracking is done by imaging.

Source: Anderson, L. S., et al. A Mouse Model to Assess Innate Immune Response to Staphylococcus aureus Infection. J. Vis. Exp. (2019).
This video ...

JoVE Encyclopedia of Experiments

Immunology

Immune Response

Host Defense Mechanism

Quantification of Inflammatory Mediators in Infected Human Tissue-Derived Cells

Source: Dousha, L. et al., <a href="https://app.jove.com/v/62572">Assessing Respiratory Immune Responses to Haemophilus Influenzae.</a>&#160;J. Vis. Exp.&#160;(2021)
This video demonstrates the quantification of inflammatory mediators during infection by incubating human lung-tissue-derived immune cells with Haemophilus influenzae. Flow cytometry is used to measure cytokine fluorescence in labeled lymphocytes, correlating with the production of pro-inflammatory cytokines in response to bacterial infection.

Source: Dousha, L. et al., Assessing Respiratory Immune Responses to Haemophilus Influenzae.&#160;J. Vis. Exp.&#160;(2021)
This video demonstrates the ...

Colonoscopic Guided Murine Wound Model: A Method to Isolate Biopsy Induced Wound Bed from Colon to Understand the Healing Process

Source: Montrose, D. C., et al. <a href="https://www.jove.com/v/60949">Performing Colonoscopic-Guided Pinch Biopsies in Mice and Evaluating Subsequent Tissue Changes.</a> J. Vis. Exp. (2021).
In this video, we describe a procedure to isolate the colonoscopic-induced wound bed at an appropriate time point for detailed molecular analysis. This analysis helps to understand the wound healing process in inflammatory conditions of the GI tract.

Source: Montrose, D. C., et al. Performing Colonoscopic-Guided Pinch Biopsies in Mice and Evaluating Subsequent Tissue Changes. J. Vis. Exp. (2021).
In ...

Collecting And Measuring Wound Exudate Biochemical Mediators In Surgical Wounds

Summary

Explore More Videos

Chapters in this video

Collecting and Measuring Nociceptive and Inflammatory Mediators in Surgical Wounds

Murine Excisional Wound Healing Model and Histological Morphometric Wound Analysis

Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels

Come to the Light Side: In Vivo Monitoring of Pseudomonas aeruginosa Biofilm Infections in Chronic Wounds in a Diabetic Hairless Murine Model

Assessment of Acute Wound Healing using the Dorsal Subcutaneous Polyvinyl Alcohol Sponge Implantation and Excisional Tail Skin Wound Models.

Digital Planimetry for Assessing Wound Closure Kinetics in a Mouse Model

Laser Capture Microdissection on Surgical Tissues to Identify Aberrant Gene Expression in Impaired Wound Healing in Type 2 Diabetes

Monitoring Neutrophil Recruitment Dynamics and Bacterial Burden at the Infection Site in a Murine Model

Quantification of Inflammatory Mediators in Infected Human Tissue-Derived Cells

Colonoscopic Guided Murine Wound Model: A Method to Isolate Biopsy Induced Wound Bed from Colon to Understand the Healing Process