Name: collecting and measuring wound exudate biochemical mediators in surgical wounds
Uploaded: 2012-10-20T14:00:00
Description: Watch this Scientific Journal Video about Collecting And Measuring Wound Exudate Biochemical Mediators In Surgical Wounds at JoVE.com

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 fo...

<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>

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 i...

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-h...

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. ...

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Research

JoVE Journal

Medicine

Biochemical Measurement of Neonatal Hypoxia

Neonatal hypoxia ischemia is characterized by inadequate blood perfusion of a tissue or a systemic lack of oxygen. This condition is thought to cause/exacerbate well documented neonatal disorders including neurological impairment 1-3. Decreased adenosine triphosphate production occurs due to a lack of oxidative phosphorylation. To compensate for this energy deprived state molecules containing high energy phosphate bonds are degraded 2. This leads to increased levels of adenosine which is subsequently degraded to inosine, hypoxanthine, xanthine, and finally to uric acid. The final two steps in this degradation process are performed by xanthine oxidoreductase. This enzyme exists in the form of xanthine dehydrogenase under normoxic conditions but is converted to xanthine oxidase (XO) under hypoxia-reperfusion circumstances 4, 5. Unlike xanthine dehydrogenase, XO generates hydrogen peroxide as a byproduct of purine degradation 4, 6. This hydrogen peroxide in combination with other reactive oxygen species (ROS) produced during hypoxia, oxidizes uric acid to form allantoin and reacts with lipid membranes to generate malondialdehyde (MDA) 7-9. Most mammals, humans exempted, possess the enzyme uricase, which converts uric acid to allantoin. In humans, however, allantoin can only be formed by ROS-mediated oxidation of uric acid. Because of this, allantoin is considered to be a marker of oxidative stress in humans, but not in the mammals that have uricase.
We describe methods employing high pressure liquid chromatography (HPLC) and gas chromatography mass spectrometry (GCMS) to measure biochemical markers of neonatal hypoxia ischemia. Human blood is used for most tests. Animal blood may also be used while recognizing the potential for uricase-generated allantoin. Purine metabolites were linked to hypoxia as early as 1963 and the reliability of hypoxanthine, xanthine, and uric acid as biochemical indicators of neonatal hypoxia was validated by several investigators 10-13. The HPLC method used for the quantification of purine compounds is fast, reliable, and reproducible. The GC/MS method used for the quantification of allantoin, a relatively new marker of oxidative stress, was adapted from Gruber et al 7. This method avoids certain artifacts and requires low volumes of sample. Methods used for synthesis of MMDA were described elsewhere 14, 15. GC/MS based quantification of MDA was adapted from Paroni et al. and Cighetti et al. 16, 17. Xanthine oxidase activity was measured by HPLC by quantifying the conversion of pterin to isoxanthopterin 18. This approach proved to be sufficiently sensitive and reproducible.

A method is described to measure biochemical markers of neonatal hypoxia-ischemia. The approach utilizes high pressure liquid chromatography (HPLC) and Gas Chromatography Mass Spectrometry (GC/MS).

Neonatal hypoxia ischemia is characterized by inadequate blood perfusion of a tissue or a systemic lack of oxygen. This condition is thought to ...

Collecting Saliva and Measuring Salivary Cortisol and Alpha-amylase in Frail Community Residing Older Adults via Family Caregivers

Salivary measures have emerged in bio-behavioral research that are easy-to-collect, minimally invasive, and relatively inexpensive biologic markers of stress. This article we present the steps for collection and analysis of two salivary assays in research with frail, community residing older adults-salivary cortisol and salivary alpha amylase. The field of salivary bioscience is rapidly advancing and the purpose of this presentation is to provide an update on the developments for investigators interested in integrating these measures into research on aging. Strategies are presented for instructing family caregivers in collecting saliva in the home, and for conducting laboratory analyses of salivary analytes that have demonstrated feasibility, high compliance, and yield quality specimens. The protocol for sample collection includes: (1) consistent use of collection materials; (2) standardized methods that promote adherence and minimize subject burden; and (3) procedures for controlling certain confounding agents. We also provide strategies for laboratory analyses include: (1) saliva handling and processing; (2) salivary cortisol and salivary alpha amylase assay procedures; and (3) analytic considerations.

We demonstrate: (1) procedures for collection of salivary samples in cognitive impaired older adults by family caregivers in the home setting, (2) procedures for measuring stress activity via salivary cortisol and alpha amylase, and (3) representative profiles. Protocols that allow researchers to study stress-linked processes advance our understanding of biological sensitivity and susceptibility.

Salivary measures have emerged in bio-behavioral research  that are easy-to-collect, minimally invasive, and relatively inexpensive  biologic markers of ...

In utero Measurement of Heart Rate in Mouse by Noninvasive M-mode Echocardiography

Congenital heart disease (CHD) is the most frequent noninfectious cause of death at birth. The incidence of CHD ranges from 4 to 50/1,000 births (Disease and injury regional estimates, World Health Organization, 2004). Surgeries that often compromise the quality of life are required to correct heart defects, reminding us of the importance of finding the causes of CHD. Mutant mouse models and live imaging technology have become essential tools to study the etiology of this disease. Although advanced methods allow live imaging of abnormal hearts in embryos, the physiological and hemodynamic states of the latter are often compromised due to surgical and/or lengthy procedures. Noninvasive ultrasound imaging, however, can be used without surgically exposing the embryos, thereby maintaining their physiology. Herein, we use simple M-mode ultrasound to assess heart rates of embryos at E18.5 in utero. The detection of abnormal heart rates is indeed a good indicator of dysfunction of the heart and thus constitutes a first step in the identification of developmental defects that may lead to heart failure.

In utero Measurement of Heart Rate in Mouse by Noninvasive M-mode Echocardiography

Ultra-high frequency ultrasound is a powerful live imaging tool to examine cardiac abnormalities in small animals. Its noninvasiveness allows maintaining the physiologic state of embryos. Herein, we show the use of M-mode ultrasound to measure the heart rates of embryos at E18.5 in utero.

Congenital heart disease (CHD) is the most frequent noninfectious cause of death at birth. The incidence of CHD ranges from 4 to 50/1,000 births (Disease ...

Demonstration of the Rat Ischemic Skin Wound Model

The propensity for chronic wounds in humans increases with ageing, disease conditions such as diabetes and impaired cardiovascular function, and unrelieved pressure due to immobility. Animal models have been developed that attempt to mimic these conditions for the purpose of furthering our understanding of the complexity of chronic wounds. The model described herein is a rat ischemic skin flap model that permits a prolonged reduction of blood flow resulting in wounds that become ischemic and resemble a chronic wound phenotype (reduced vascularization, increased inflammation and delayed wound closure). It consists of a bipedicled dorsal flap with 2 ischemic wounds placed centrally and 2 non-ischemic wounds lateral to the flap as controls. A novel addition to this ischemic skin flap model is the placement of a silicone sheet beneath the flap that functions as a barrier and a splint to prevent revascularization and reduce contraction as the wounds heal. Despite the debate of using rats for wound healing studies due to their quite distinct anatomic and physiologic differences compared to humans (i.e., the presence of a panniculus carnosus muscle, short life-span, increased number of hair follicles, and their ability to heal infected wounds) the modifications employed in this model make it a valuable alternative to previously developed ischemic skin flap models.

The rat, due to its size, availability, and rather docile behavior, has been utilized as a research model for many years. The goal of this protocol is to utilize the rat as an ischemic skin wound healing model to provide valuable insight into the pathophysiology of chronic wounds.

The propensity for chronic wounds in humans increases with ageing, disease conditions such as diabetes and impaired cardiovascular function, and ...

Intravital Microscopy of Tumor-associated Vasculature Using Advanced Dorsal Skinfold Window Chambers on Transgenic Fluorescent Mice

Tumor and tumor vessel development, as well as tumor response to therapeutics, are highly dynamic biological processes. Histology provides static information and is often not sufficient for a correct interpretation. Intravital evaluation, in which a process is followed in time, provides extra and often unexpected information. With the creation of transgenic animals expressing cell-specific markers and live cell tracers, improvements to imaging equipment, and the development of several imaging chambers, intravital microscopy has become an important tool to better understand biological processes. This paper describes an experimental design for the investigation of tumor vessel development and of therapeutic effects in a spatial and temporal manner. Using this setup, the stage of vessel development, tip cell and lumen formation, blood flow, extravasation, an established vascular bed, and vascular destruction can be visualized and followed. Furthermore, therapeutic effects, intratumoral fate, and the localization of chemotherapeutic compounds can also be followed.

This protocol describes the intravital imaging of transgenic mice expressing cell-specific fluorescent markers. Intravital imaging provides a non-invasive method for high-resolution observations in living animals using implantable windows through which the microscopic visualization of processes is possible. This method is especially useful to study longitudinal processes.

Tumor and tumor vessel development, as well as tumor response to therapeutics, are highly dynamic biological processes. Histology provides static ...

Using In Vitro Live-cell Imaging to Explore Chemotherapeutics Delivered by Lipid-based Nanoparticles

Conventional imaging techniques can provide detailed information about cellular processes. However, this information is based on static images in an otherwise dynamic system, and successive phases are easily overlooked or misinterpreted. Live-cell imaging and time-lapse microscopy, in which living cells can be followed for hours or even days in a more or less continuous fashion, are therefore very informative. The protocol described here allows for the investigation of the fate of chemotherapeutic nanoparticles after the delivery of doxorubicin (dox) in living cells. Dox is an intercalating agent that must be released from its nanocarrier to become biologically active. In spite of its clinical registration for more than two decades, its uptake, breakdown, and drug release are still not fully understood. This article explores the hypothesis that lipid-based nanoparticles are taken up by the tumor cells and are slowly degraded. Released dox is then translocated to the nucleus. To prevent fixation artifacts, live-cell imaging and time-lapse microscopy, described in this experimental procedure, can be applied.

Using In Vitro Live-cell Imaging to Explore Chemotherapeutics Delivered by Lipid-based Nanoparticles

Live-cell imaging is a powerful tool to visualize dynamic processes. The examination of fixed cells provides only static pictures, which can lead to misinterpretation and confusion about the process. This work presents a method to study uptake, drug release, and intracellular localization of liposomal nanoparticles in living cells.

Conventional imaging techniques can provide detailed information about cellular processes. However, this information is based on static images in an ...

Collecting Hair Samples for Hair Cortisol Analysis in African Americans

The hormone cortisol is typically assessed in saliva, serum, or urine samples. More recently, cortisol has been successfully extracted from hair, including humans. The advantage of hair cortisol concentration is that it reflects a retrospective representation of hypothalamic-pituitary-adrenal (HPA) axis function over time, much like hemoglobin A1C represents glycemic control. However, obtaining hair samples can be challenging, due to the cultural beliefs and hair care practices of minority participants. For example, African Americans may be reluctant to provide samples. Additionally, few researchers are trained to collect hair samples from African Americans. The purpose of this paper is to present a culturally informed protocol to help researchers obtain hair samples from African Americans. To illustrate the representative results of this protocol implementation, de-identified data from African Americans that participated in a community-based study on chronic stress are provided. Hair practice preferences are assessed. The participants are made comfortable by showing pictures of hair samples prior to cutting their hair. The single strain twist and gently pull method is used to collect approximately 30 - 50 strands of hair from the posterior vertex region of the scalp. This protocol will significantly improve collection of hair samples from African Americans.

Hair cortisol concentration analysis provides an alternative to traditional measures of cortisol; however, to collect hair samples from African Americans, scientists need to be culturally informed and competent. The purpose of this protocol is to demonstrate a culturally informed technique to collect hair samples for cortisol analysis from African Americans.

The hormone cortisol is typically assessed in saliva, serum, or urine samples. More recently, cortisol has been successfully extracted from hair, ...

Application of End-to-end Anastomosis in Robotic Central Pancreatectomy

Central pancreatectomy is carried out for the treatment of benign or low-malignant potential tumors located in the pancreatic neck or proximal part of pancreatic body. With technological development, the robotic surgical system has shown its advantage in minimally invasive surgery and been increasingly applied in central pancreatectomy. However, reconstruction of the continuity of pancreas with end-to-end anastomosis after robotic central pancreatectomy has not been applied. In this study, we report surgical techniques for robotic central pancreatectomy with end-to-end anastomosis. The pancreas is reconstructed by duct-to-duct anastomosis of the pancreatic duct with a pancreatic stent inserted in the two stumps of pancreatic duct, and by end-to-end anastomosis of the pancreatic parenchyma. Compared with traditional central pancreatectomy with pancreaticoenteric anastomosis, this approach decreases the operative injury to the patient, and also conserves the integrity and continuity of the digestive duct and pancreatic duct. The robotic surgical system integrated with multiple instruments with flexible and precise movement is particularly suitable for the dissection and reconstruction of the pancreatic duct. We found that robotic central pancreatectomy with end-to-end anastomosis is safe and feasible, and we need more experience to evaluate its best indications and long-term outcomes.

The robotic central pancreatectomy with end-to-end anastomosis is feasible and safe for tumor in the pancreatic neck and proximal portion of pancreatic body. The operative techniques of this operation are presented.

Central pancreatectomy is carried out for the treatment of benign or low-malignant potential tumors located in the pancreatic neck or proximal part of ...

Protocol to Create Chronic Wounds in Diabetic Mice

Chronic wounds develop as a result of defective regulation in one or more complex cellular and molecular processes involved in proper healing. They impact ~6.5M people and cost ~$40B/year in the US alone. Although a significant effort has been invested in understanding how chronic wounds develop in humans, fundamental questions remain unanswered. Recently, we developed a novel mouse model for diabetic chronic wounds that have many characteristics of human chronic wounds. Using db/db-/- mice, we can generate chronic wounds by inducing high levels of oxidative stress (OS) in the wound tissue immediately after wounding, using a one-time treatment with inhibitors specific to the antioxidant enzymes catalase and glutathione peroxidase. These wounds have high levels of OS, develop biofilm naturally, become fully chronic within 20 days after treatment and can remain open more for more than 60 days. This novel model has many features of diabetic chronic wounds in humans and therefore can contribute significantly to advancing fundamental understanding of how wounds become chronic. This is a major breakthrough because chronic wounds in humans cause significant pain and distress to patients and result in amputation if unresolved. Moreover, these wounds are very expensive and time-consuming to treat, and lead to significant loss of personal income to patients. Advancements in this field of study through the use of our chronic wound model can significantly improve health care for millions who suffer under this debilitating condition. In this protocol, we describe in great detail the procedure to cause acute wounds to become chronic, which has not been done before.

Chronic wounds are developed from acute wounds on a diabetic mouse model by inducing high levels of oxidative stress after a full-thickness cutaneous wound. The wound is treated with inhibitors for catalase and glutathione peroxidase, resulting in impaired healing and biofilm development by bacteria present in the skin microbiome.

Chronic wounds develop as a result of defective regulation in one or more complex cellular and molecular processes involved in proper healing. They impact ...

Corneal Epithelial Abrasion with Ocular Burr As a Model for Cornea Wound Healing

The murine cornea provides an excellent model to study wound healing. The cornea is the outermost layer of the eye, and thus is the first defense to injury. In fact, the most common type of eye injury found in clinic is a corneal abrasion. Here, we utilize an ocular burr to induce an abrasion resulting in removal of the corneal epithelium in vivo on anesthetized mice. This method allows for targeted and reproducible epithelial disruption, leaving other areas intact. In addition, we describe the visualization of the abraded epithelium with fluorescein staining and provide concrete advice on how to visualize the abraded cornea. Then, we follow the timeline of wound healing 0, 18, and 72 h after abrasion, until the wound is re-epithelialized. The epithelial abrasion model of corneal injury is ideal for studies on epithelial cell proliferation, migration and re-epithelialization of the corneal layers. However, this method is not optimal to study stromal activation during wound healing, because the ocular burr does not penetrate to the stromal cell layers. This method is also suitable for clinical applications, for example, pre-clinical test of drug effectiveness.

This protocol describes a method to inflict an abrasion to the ocular surface of the mouse, and to follow the wound healing process thereafter. The protocol takes advantage of an ocular burr to partially remove the surface epithelium of the eye in anaesthetized mice.

The murine cornea provides an excellent model to study wound healing. The cornea is the outermost layer of the eye, and thus is the first defense to ...