Preparazione del donatore e Harvest Cuore: <ol><li style="text-align: left"> Il mouse è anestetizzato con un&#39;iniezione intraperitoneale di supina pentobarbital e immessi sul campo operatorio. </li><li style="text-align: left"> Una lunga incisione addominale mediana è fatto. Contenuto addominale sono ritratta con una garza a sinistra al fine di esporre l&#39;aorta addominale e la vena cava inferiore. </li><li style="text-align: left"> 1 ml di eparina (10u/ml) viene iniettato nella vena cava inferiore per eparinizzazione. </li><li style="text-align: left"> La toracotomia è fatto: le costole sono divisi su entrambi i lati della colonna vertebrale e la parete toracica anteriore è indebitate fino ad esporre il cuore. </li><li style="text-align: left"> La vena cava inferiore, la vena cava superiore e la vena azygos sono legatura con 6-0 seta e diviso superiore alla legature. </li><li style="text-align: left"> L&#39;aorta ascendente e l&#39;arteria polmonare sono separati e divisi per quanto distalmente possibile. </li><li style="text-align: left"> Le vene polmonari sono legata e sezionata distale ai legami. </li><li style="text-align: left"> Il cuore è perfuso con 4 soluzione C o salina. </li><li style="text-align: left"> Il cuore è conservato in una soluzione salina ghiacciata. </li></ol> Destinatario Preparazione e Trapianto <ol><li style="text-align: left"> Il mouse è anestetizzato con un&#39;iniezione intraperitoneale di supina pentobarbital e immessi sul campo operatorio. </li><li style="text-align: left"> Una lunga incisione addominale mediana è fatto. Contenuto addominale sono ritratta fuori l&#39;addome con una garza per esporre l&#39;aorta addominale e la vena cava inferiore. </li><li style="text-align: left"> I rami dell&#39;aorta addominale e la vena cava inferiore sono esposti e legatura 10-0 con punti di sutura. </li><li style="text-align: left"> Le legature prossimale e distale sono disposte intorno al aorta e vena cava inferiore, rispettivamente. </li><li style="text-align: left"> Il venotomy è fatto in vena cava inferiore del ricevente con un ago da 30 gauge. L&#39;apertura è poi estesa ad una lunghezza uguale aorta polmonare del donatore con micro-forbici. </li><li style="text-align: left"> Il aortotomy è realizzato in dell&#39;aorta addominale del destinatario con un ago da 30 gauge. </li><li style="text-align: left"> L&#39;aorta addominale aperta e la vena cava inferiore sono irrigati con soluzione salina. </li><li style="text-align: left"> Il cuore del donatore è posizionato sul lato sinistro dell&#39;addome del destinatario ed è coperto con una garza. </li><li style="text-align: left"> Le suture sono messi a apici prossimale e distale del destinatario aorta addominale con aorta ascendente del donatore. </li><li style="text-align: left"> L&#39;anastomosi del lato destro della aorta addominale del destinatario e dell&#39;aorta ascendente del donatore sono completati con suture di continuare. </li><li style="text-align: left"> Due punti di sutura soggiorno sono fatte prima al vertice prossimale e distale del vertice del destinatario vena cava inferiore con arteria polmonare del donatore per l&#39;anastomosi dell&#39;arteria polmonare del donatore e del ricevente vena cava inferiore. </li><li style="text-align: left"> La parete sinistra della vena cava inferiore e l&#39;arteria polmonare donatore viene chiusa con sutura continua nella parte interna della vena cava inferiore. </li><li style="text-align: left"> Dopo un nodo con la sutura prossimale soggiorno apice, la parete destra della vena cava inferiore e l&#39;arteria polmonare del donatore sono chiuse con punti di sutura continua al di fuori della vena cava inferiore. </li><li style="text-align: left"> Il cuore del donatore è girato verso il lato destro dell&#39;addome del destinatario. La parete destra della aorta addominale del destinatario e anastomosi aorta ascendente del donatore sono chiusi con continui punti di sutura. </li><li style="text-align: left"> Dopo anastomosi è fatto, la legatura distale viene rimosso per controllare il sanguinamento dal anastomosi. </li><li style="text-align: left"> Se c&#39;è poco o nessun sanguinamento dal anastomosi, la legatura prossimale viene rimosso. Il cuore del donatore si riempie di sangue immediatamente il colore del cuore diventa rossa e comincia a battere di nuovo. </li><li style="text-align: left"> Gli intestini sono restituiti al ventre, che si chiude con 6-0 punti di sutura continua. </li><li style="text-align: left"> Il mouse destinatario è piazzato in una zona calda. Dopo un&#39;ora il destinatario recupera. </li></ol>

<ol>
	<li>Corry, R. o. b. e. r. t. . J., Winn, H. e. n. r. y. . J., Russell, P. a. u. l. . S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primarily+vascularized+allografts+of+heart+in+mice.">Primarily vascularized allografts of heart in mice.</a> Transplantation. 16, 343-350 (1973).</li></ol>

Risultati Abbiamo effettuato con successo più di 1000 casi di trapianto di cuore eterotopico nei topi e ha raggiunto oltre il 90% tasso di successo in diversi ceppi di topi, tra cui wild-type, transgenici e topi knockout del gene. Discussione Dal Drs. Corry e Russell introdotto trapianto eterotopico cuore nei topi, nel 1973, questo modello ha dimostrato di essere particolarmente utile per studiare la risposta immunitaria rifiuto e lo sviluppo di nuove strategie immunosoppressive. Qu...

heterotopic heart transplantation in mice

Il trapianto eterotopico cuore del mouse è stato ampiamente utilizzato da quando è stato introdotto da Drs. Corry e Russell nel 1973. E &#39;particolarmente utile per lo studio rifiuto e risposta immunitaria ora che i nuovi transgenici e topi knockout del gene sono disponibili, e un gran numero di reagenti immunologici sono stati sviluppati. Il modello di trapianto di cuore è meno rigorosi rispetto ai modelli di trapianto della pelle, anche se tecnicamente più impegnativo. Abbiamo sviluppato una tecnica hanno modificato e completato oltre 1000 casi di successo del trapianto di cuore eterotopico nei topi. Quando si effettuano anastomosi dell&#39;aorta ascendente e l&#39;aorta addominale, due punti di sutura soggiorno siano messi a apici prossimale e distale del destinatario aorta addominale dell&#39;aorta ascendente con il donatore s, quindi utilizzando 11-0 sutura per anastomosi su entrambi i lati dell&#39;aorta con suture di continuare. Le suture soggiorno rendere l&#39;anastomosi più facile e 11-0 è una dimensione di sutura ideale per evitare il sanguinamento e trombosi. Quando si effettuano anastomosi dell&#39;arteria polmonare e la vena cava inferiore, due suture sono fatte al vertice prossimale e distale all&#39;apice del destinatario s vena cava inferiore con arteria polmonare del donatore s. La parete sinistra della vena cava inferiore e l&#39;arteria polmonare donatore s è chiusa con sutura continua in parte interna della vena cava inferiore dopo, un nodo con il soggiorno apice prossimale sutura la parete destra della vena cava inferiore e l&#39;arteria polmonare del donatore s sono chiuse con punti di sutura continua al di fuori della grotta vena 10-0 con punti di sutura. Questo metodo è più facile da eseguire, perché anastomosi è fatta solo da una parte della vena cava inferiore e 10-0 suture è la dimensione giusta per evitare di sanguinamento e trombosi. In questo articolo, forniamo i dettagli della tecnica per integrare il video.

Watch this Scientific Journal Video about Heterotopic Heart Transplantation in Mice at JoVE.com

Heterotopic Heart Transplantation in Mice

Il modello di topo eterotopica trapianto di cuore è stato provato da molti ricercatori ad essere un metodo importante per lo studio dei meccanismi di rifiuto e di risposta immunitaria. Tuttavia, i metodi impiegati sono ancora difficili. Modificando le tecniche standard che abbiamo avuto successo con più di 1000 trapianti.

Il trapianto cardiaco eterotopico nel Mice

The mouse heterotopic heart transplantation has been used widely since it was introduced by Drs. Corry and Russell in 1973. It is particularly valuable ...

heterotopic-heart-transplantation-in-mice

Research

JoVE Journal

Biology

29.4K Views.  University of California, San Francisco - UCSF. Il modello di topo eterotopica trapianto di cuore è stato provato da molti ricercatori ad essere un metodo importante per lo studio dei meccanismi di rifiuto e di risposta immunitaria. Tuttavia, i metodi impiegati sono ancora difficili. Modificando le tecniche standard che abbiamo avuto successo con più di 1000 trapianti.

Video: Heterotopic Heart Transplantation in Mice

Small Bowel Transplantation In Mice

Since 1990, the development of tacrolimus-based immunosuppression and improved surgical techniques, the increased array of potent immunosuppressive medications, infection prophylaxis, and suitable patient selection helped improve actuarial graft and patient survival rates for all types of intestine transplantation. Patients with irreversible intestinal failure and complications of parenteral nutrition should now be routinely considered for small intestine transplantation. However, Survival rates for small intestinal transplantation have been slow to improve compares increasingly favorably with renal, liver, heart and lung. The small bowel transplantation is still unsatisfactory compared with other organs. Further progress may depend on better understanding of immunology and physiology of the graft and can be greatly facilitated by animal models. A wider use of mouse small bowel transplantation model is needed in the study of immunology and physiology of the transplantation gut as well as efficient methods in diagnosing early rejection. However, this model is limited to use because the techniques involved is an extremely technically challenging. We have developed a modified technique. When making anastomosis of portal vein and inferior vena cava, two stay sutures are made at the proximal apex and distal apex of the recipient s inferior vena cava with the donor s portal vein. The left wall of the inferior vena cava and donor s portal vein is closed with continuing sutures in the inside of the inferior vena cava after, after one knot with the proximal apex stay suture the right wall of the inferior vena cava and the donor s portal vein are closed with continuing sutures outside the inferior vena cave with 10-0 sutures. This method is easier to perform because anastomosis is made just on the one side of the inferior vena cava and 10-0 sutures is the right size to avoid bleeding and thrombosis.  In this article, we provide details of the technique to supplement the video.

The mouse small bowel transplantation model has been recognized as an important tool to study mechanismes of immune rejection and screen new immunosuppressive drugs. However, this model is limited to use because the techniques involved is an extremely technically challenge. Now we introduce the modified technique.

Trapianto di intestino piccolo Nei topi

Since 1990, the development of tacrolimus-based immunosuppression and improved surgical techniques, the increased array of potent immunosuppressive ...

Ricerca

Biologia

Transplantation of Pancreatic Islets Into the Kidney Capsule of Diabetic Mice

Our protocol was developed to cleanly and easily deliver islets or cells under the kidney capsule of diabetic or normal mice. We found that it was easier to concentrate the islets or cells into pellets in the final delivery tubing (PE50) used to transplant the cells under the kidney capsule. This technique provides both speed and ease while reducing any undue stress to the cells or to the mouse.

Loading: Settled, hand picked, islets or pelleted cells are carefully aspirated off the bottom of a 1.5 mL microcentrifuge tube using a p200 pipetteman and a straight, thin-wall pipette tip. A length of PE50 tubing is attached to the pipette tip using a small silicone adapter tubing. Cells are allowed to settle, in the tip, and then are transferred to the PE50 tubing by slowly dialing the pipetteman. Once the cells are near the end of the PE50 tubing, a kink is made and the silicone adaptor tubing is placed over the kink. The PE50 tubing is transferred to a 15 mL conical containing a cut 5 mL pipet, and the PE50 tubing is taped over the side of the 5 mL pipet to prevent curling during centrifuging. Cells are allowed to reach 1,000 rpm and stopped.
Transplantation: Recipient mice are anesthetized, shaved, and cleaned. A small incision is made on the left flank of the mouse and the kidney is exposed. The kidney, fat, and tissue are kept moist with normal saline swab. The distal end of the PE50 is attached to a Hamilton screw drive syringe, containing a pipette tip, using the silicone adaptor tubing. A small nick is made on the right flank side of the kidney, not too large nor too deep. The beveled end of the PE50 tubing, nearest the cells, is carefully placed under the capsule, the tubing is moved around gently to make space while swabbing normal saline; a dry capsule can tear easily. A small air bubble is delivered under the capsule by slowly dialing the syringe screw drive. Islets are then slowly delivered behind the air bubble. Once the islets have been delivered kidney homeostasis is maintained and the knick is cauterized with low heat. The kidney is placed back into the cavity and the peritoneum and skin are sutured and stapled. Mice are immediately treated with Flunixin and Buprenorphine s.q. and placed in a cage on a heating pad.

Our protocol was developed to cleanly and easily deliver islets or cells under the kidney capsule of mice. Cells are concentrated into pellets in the final tubing used for transplanting the cells under the kidney capsule. The ease of this technique reduces stress to the cells and the mouse.

Il trapianto di isole pancreatiche nella capsula renale di topi diabetici

Our protocol was developed to cleanly and easily deliver islets or cells under the kidney capsule of diabetic or normal mice.  We found that it was easier ...

Murine Skin Transplantation

As one of the most stringent and least technically challenging models, skin transplantation is a standard method to assay host T cell responses to MHC-disparate donor antigens. The aim of this video-article is to provide the viewer with a step-by-step visual demonstration of skin transplantation using the mouse model. The protocol is divided into 5 main components: 1) harvesting donor skin; 2) preparing recipient for transplant; 3) skin transplant; 4) bandage removal and monitoring graft rejection; 5) helpful hints. Once proficient, the procedure itself should take &lt;10 min to perform.

Allogeneic skin transplantation is a standard model to assay host T cell responses to MHC-disparate donor antigens. This video-article provides a visual tutorial of each step involved in performing a BALB/c--&gt;C57BL/6 skin transplant.

Trapianto di pelle murina

As one of the most stringent and least technically challenging models, skin transplantation is a standard method to assay host T cell responses to ...

Visualizing the Beating Heart in Drosophila

The Drosophila heart has recently emerged as a good model system for examining the genetic, cellular, and molecular mechanisms underlying function in myogenic hearts. A key step in examining heart function in the fly is finding a way to access the heart in a manner that preserves its myogenic function while still allowing the beating heart organ to be observed and recorded. Two different methods for observing and recording the beating heart in both larva and adult Drosophila are described here. Our semi-intact preparation using adult flies allows clear visualization of the abdominal heart without interference from the pigmented cuticle and overlying fat bodies. To record larval heart beats it is necessary to immobilize the larva, which minimizes body wall movements thereby reducing heart movements that are not associated with myocardial contractions. Our methodologies produce stable adult and larval heart preparations that can beat for hours at rates of 1-3 Hz.

Visualizing the Beating Heart in Drosophila

Technique required for visualizing the beating heart in larval and adult Drosophila are presented. Each life stage requires a different methodology.

Visualizzare il cuore pulsante di Drosophila</em

The Drosophila heart has recently emerged as a good model system for examining the genetic, cellular, and molecular mechanisms underlying function in ...

Heterotopic and Orthotopic Tracheal Transplantation in Mice used as Models to Study the Development of  Obliterative Airway Disease

Obliterative airway disease (OAD) is the major complication after lung transplantations that limits long term survival (1-7).
To study the pathophysiology, treatment and prevention of OAD, different animal models of tracheal transplantation in rodents have been developed (1-7). Here, we use two established models of trachea transplantation, the heterotopic and orthotopic model and demonstrate their advantages and limitations.
For the heterotopic model, the donor trachea is wrapped into the greater omentum of the recipient, whereas the donor trachea is anastomosed by end-to-end anastomosis in the orthotopic model.
In both models, the development of obliterative lesions histological similar to clinical OAD has been demonstrated (1-7).
This video shows how to perform both, the heterotopic as well as the orthotopic tracheal transplantation technique in mice, and compares the time course of OAD development in both models using histology.

This video shows and compares two experimental models to study the development of obliterative airway disease (OAD) in mice, the heterotopic and orthotopic tracheal transplantation model.

Eterotopica e trapianto ortotopico tracheale in topi utilizzati come modelli per studiare lo sviluppo della malattia delle vie aeree obliterante

Obliterative airway disease (OAD) is the major complication after lung transplantations that limits long term survival (1-7).
To study the ...

Preparation of embryos for Electron Microscopy of the Drosophila embryonic heart tube

The morphogenesis of the Drosophila embryonic heart tube has emerged as a valuable model system for studying cell migration, cell-cell adhesion and cell shape changes during embryonic development. One of the challenges faced in studying this structure is that the lumen of the heart tube, as well as the membrane features that are crucial to heart tube formation, are difficult to visualize in whole mount embryos, due to the small size of the heart tube and intra-lumenal space relative to the embryo. The use of transmission electron microscopy allows for higher magnification of these structures and gives the advantage of examining the embryos in cross section, which easily reveals the size and shape of the lumen. In this video, we detail the process for reliable fixation, embedding, and sectioning of late stage Drosophila embryos in order to visualize the heart tube lumen as well as important cellular structures including cell-cell junctions and the basement membrane.

Preparation of embryos for Electron Microscopy of the Drosophila embryonic heart tube

We describe a process for fixation, embedding, sectioning, and imaging of late stage Drosophila embryos for Trasmission Electron Microscopy of the embryonic heart tube. This technique allows for the visualization of the heart tube lumen as well as the basement membrane, which lines the lumen of the heart.

Preparazione di embrioni per la microscopia elettronica del Drosophila Tubo cuore embrionale

The morphogenesis of the Drosophila  embryonic heart tube has emerged as a valuable model system for studying cell migration, cell-cell adhesion and cell ...

Quantification of &gamma;H2AX Foci in Response to Ionising Radiation

DNA double-strand breaks (DSBs), which are induced by either endogenous metabolic processes or by exogenous sources, are one of the most critical DNA lesions with respect to survival and preservation of genomic integrity. An early response to the induction of DSBs is phosphorylation of the H2A histone variant, H2AX, at the serine-139 residue, in the highly conserved C-terminal SQEY motif, forming &gamma;H2AX1. Following induction of DSBs, H2AX is rapidly phosphorylated by the phosphatidyl-inosito 3-kinase (PIKK) family of proteins, ataxia telangiectasia mutated (ATM), DNA-protein kinase catalytic subunit and ATM and RAD3-related (ATR)2. Typically, only a few base-pairs (bp) are implicated in a DSB, however, there is significant signal amplification, given the importance of chromatin modifications in DNA damage signalling and repair. Phosphorylation of H2AX mediated predominantly by ATM spreads to adjacent areas of chromatin, affecting approximately 0.03% of total cellular H2AX per DSB2,3. This corresponds to phosphorylation of approximately 2000 H2AX molecules spanning ~2 Mbp regions of chromatin surrounding the site of the DSB and results in the formation of discrete &gamma;H2AX foci which can be easily visualized and quantitated by immunofluorescence microscopy2. The loss of &gamma;H2AX at DSB reflects repair, however, there is some controversy as to what defines complete repair of DSBs; it has been proposed that rejoining of both strands of DNA is adequate however, it has also been suggested that re-instatement of the original chromatin state of compaction is necessary4-8. The disappearence of &gamma;H2AX involves at least in part, dephosphorylation by phosphatases, phosphatase 2A and phosphatase 4C5,6. Further, removal of &gamma;H2AX by redistribution involving histone exchange with H2A.Z has been implicated7,8. Importantly, the quantitative analysis of &gamma;H2AX foci has led to a wide range of applications in medical and nuclear research. Here, we demonstrate the most commonly used immunofluorescence method for evaluation of initial DNA damage by detection and quantitation of &gamma;H2AX foci in &gamma;-irradiated adherent human keratinocytes9.

Quantification of &amp;#947;H2AX Foci in Response to Ionising Radiation

Quantification of DNA double-strand streaks using &gamma;H2AX formation as a molecular marker has become an invaluable tool in radiation biology. Here we demonstrate the use of an immunofluorescence assay for quantification of &gamma;H2AX foci after exposure of cells to radiation.

Quantificazione dei γH2AX Foci in risposta alle radiazioni ionizzanti

DNA double-strand breaks (DSBs), which are induced by either endogenous metabolic processes or by exogenous sources, are one of the most critical DNA ...

Evaluation of the Spatial Distribution of &gamma;H2AX following Ionizing Radiation

An early molecular response to DNA double-strand breaks (DSBs) is phosphorylation of the Ser-139 residue within the terminal SQEY motif of the histone H2AX1,2. This phosphorylation of H2AX is mediated by the phosphatidyl-inosito 3-kinase (PI3K) family of proteins, ataxia telangiectasia mutated (ATM), DNA-protein kinase catalytic subunit and ATM and RAD3-related (ATR)3. The phosphorylated form of H2AX, referred to as &gamma;H2AX, spreads to adjacent regions of chromatin from the site of the DSB, forming discrete foci, which are easily visualized by immunofluorecence microscopy3. Analysis and quantitation of &gamma;H2AX foci has been widely used to evaluate DSB formation and repair, particularly in response to ionizing radiation and for evaluating the efficacy of various radiation modifying compounds and cytotoxic compounds4.
Given the exquisite specificity and sensitivity of this de novo marker of DSBs, it has provided new insights into the processes of DNA damage and repair in the context of chromatin. For example, in radiation biology the central paradigm is that the nuclear DNA is the critical target with respect to radiation sensitivity. Indeed, the general consensus in the field has largely been to view chromatin as a homogeneous template for DNA damage and repair. However, with the use of &gamma;H2AX as molecular marker of DSBs, a disparity in &gamma;-irradiation-induced &gamma;H2AX foci formation in euchromatin and heterochromatin has been observed5-7. Recently, we used a panel of antibodies to either mono-, di- or tri- methylated histone H3 at lysine 9 (H3K9me1, H3K9me2, H3K9me3) which are epigenetic imprints of constitutive heterochromatin and transcriptional silencing and lysine 4 (H3K4me1, H3K4me2, H3K4me3), which are tightly correlated actively transcribing euchromatic regions, to investigate the spatial distribution of &gamma;H2AX following ionizing radiation8. In accordance with the prevailing ideas regarding chromatin biology, our findings indicated a close correlation between &gamma;H2AX formation and active transcription9. Here we demonstrate our immunofluorescence method for detection and quantitation of &gamma;H2AX foci in non-adherent cells, with a particular focus on co-localization with other epigenetic markers, image analysis and 3D-modeling.

Evaluation of the Spatial Distribution of &amp;#947;H2AX following Ionizing Radiation

Microscopic analysis of &gamma;H2AX foci, which form following the phosphorylation of H2AX at Ser-139 in response to DNA double-strand breaks, has become an invaluable tool in radiation biology. Here we used an antibody to mono-methylated histone H3 at lysine 4 as an epigenetic marker of actively transcribing euchromatin, to evaluate the spatial distribution of radiation-induced &gamma;H2AX formation within the nucleus.

Valutazione della distribuzione spaziale delle γH2AX seguenti radiazioni ionizzanti

An early molecular response to DNA double-strand breaks (DSBs) is phosphorylation of the Ser-139 residue within the terminal SQEY motif of the histone ...

Clonogenic Assay: Adherent Cells

The clonogenic (or colony forming) assay has been established for more than 50 years; the original paper describing the technique was published in 19561. Apart from documenting the method, the initial landmark study generated the first radiation-dose response curve for X-ray irradiated mammalian (HeLa) cells in culture1. Basically, the clonogenic assay enables an assessment of the differences in reproductive viability (capacity of cells to produce progeny; i.e. a single cell to form a colony of 50 or more cells) between control untreated cells and cells that have undergone various treatments such as exposure to ionising radiation, various chemical compounds (e.g. cytotoxic agents) or in other cases genetic manipulation. The assay has become the most widely accepted technique in radiation biology and has been widely used for evaluating the radiation sensitivity of different cell lines. Further, the clonogenic assay is commonly used for monitoring the efficacy of radiation modifying compounds and for determining the effects of cytotoxic agents and other anti-cancer therapeutics on colony forming ability, in different cell lines. A typical clonogenic survival experiment using adherent cells lines involves three distinct components, 1) treatment of the cell monolayer in tissue culture flasks, 2) preparation of single cell suspensions and plating an appropriate number of cells in petri dishes and 3) fixing and staining colonies following a relevant incubation period, which could range from 1-3 weeks, depending on the cell line. Here we demonstrate the general procedure for performing the clonogenic assay with adherent cell lines with the use of an immortalized human keratinocyte cell line (FEP-1811)2. Also, our aims are to describe common features of clonogenic assays including calculation of the plating efficiency and survival fractions after exposure of cells to radiation, and to exemplify modification of radiation-response with the use of a natural antioxidant formulation.

The applicability of the clonogenic assay for evaluating reproductive viability has been established for more than 50 years. Here we demonstrate the general procedure for performing the clonogenic assay with adherent cells.

Clonogenica saggio: cellule aderenti

The clonogenic (or colony forming) assay has been established for more than 50 years; the original paper describing the technique was published in 19561. ...

Germ Cell Transplantation and Testis Tissue Xenografting in Mice

Germ cell transplantation was developed by Dr. Ralph Brinster and colleagues at the University of Pennsylvania in 19941,2. These ground-breaking studies showed that microinjection of germ cells from fertile donor mice into the seminiferous tubules of infertile recipient mice results in donor-derived spermatogenesis and sperm production by the recipient animal2. The use of donor males carrying the bacterial &beta;-galactosidase gene allowed identification of donor-derived spermatogenesis and transmission of the donor haplotype to the offspring by recipient animals1. Surprisingly, after transplantation into the lumen of the seminiferous tubules, transplanted germ cells were able to move from the luminal compartment to the basement membrane where spermatogonia are located3. It is generally accepted that only SSCs are able to colonize the niche and re-establish spermatogenesis in the recipient testis. Therefore, germ cell transplantation provides a functional approach to study the stem cell niche in the testis and to characterize putative spermatogonial stem cells. To date, germ cell transplantation is used to elucidate basic stem cell biology, to produce transgenic animals through genetic manipulation of germ cells prior to transplantation4,5, to study Sertoli cell-germ cell interaction6,7, SSC homing and colonization3,8, as well as SSC self-renewal and differentiation9,10.
Germ cell transplantation is also feasible in large species11. In these, the main applications are preservation of fertility, dissemination of elite genetics in animal populations, and generation of transgenic animals as the study of spermatogenesis and SSC biology with this technique is logistically more difficult and expensive than in rodents. Transplantation of germ cells from large species into the seminiferous tubules of mice results in colonization of donor cells and spermatogonial expansion, but not in their full differentiation presumably due to incompatibility of the recipient somatic cell compartment with the germ cells from phylogenetically distant species12. An alternative approach is transplantation of germ cells from large species together with their surrounding somatic compartment. We first reported in 2002, that small fragments of testis tissue from immature males transplanted under the dorsal skin of immunodeficient mice are able to survive and undergo full development with the production of fertilization competent sperm13. Since then testis tissue xenografting has been shown to be successful in many species and emerged as a valuable alternative to study testis development and spermatogenesis of large animals in mice14.

Protocols for germ cell transplantation and testis tissue xenografting are described. Germ cell transplantation results in donor-derived spermatogenesis in recipient testes and represents a functional reconstitution assay for identification of spermatogonial stem cells (SSCs). Testis tissue xenografting reproduces testis development and spermatogenesis of various donor species in recipient mice.

Germ trapianto di cellule e di tessuto testicolare xenotrapianto in topi

Germ cell transplantation was developed by Dr. Ralph Brinster and colleagues at the University of Pennsylvania in 19941,2. These ground-breaking studies ...