Magister Scientiae (Medical Bioscience) - MSc(MBS) / Athymic nude mouse models have been extensively used to study biological behaviour of normal and diseased human tissues. In such models, immune-deficient mice act as hosts for cysts constructed from human material. A unique biocyst model that entails transplantation of human vaginal cysts into athymic nude mice has been implemented to study diseases of oral mucosa. To date, only one immunohistochemical study of this biocyst model has been reported. Nevertheless, conclusions made in that study were only based on the observed expression patterns of human and murine markers. Statistical assessment of immunohistochemical data had been omitted by the investigator. Therefore, the objective of this study was to further delineate the immunohistochemical profile of normal human vaginal tissue and human vaginal tissue that had been xenografted into nude mice.Experimental cysts constructed from human vaginal mucosa were xenografted into athymic nude mice and harvested 9-weeks post transplantation. Immunohistochemical analysis of normal human vaginal tissue and human vaginal tissue that had been xenografted into nude mice was performed using a panel of human and murine markers. Expression patterns of human and murine markers were assessed. Human markers included cytokeratin 1,cytokeratin 5, cytokeratin 13, cytokeratin 14, collagen type IV, laminin, elastin, fibronectin,Langerhans cells and VEGFR-3. Murine markers included collagen type IV, laminin,fibronectin, Langerhans cells and VEGFR-2. Staining intensities were quantified and statistically analysed using one-way ANOVA with subsequent Friedman’s test for multiple comparisons. Since the sample size was small, the power of the test statistic was enhanced by including Dunn’s post-test for further multiple comparisons. A strong positive expression of all cytokeratins was detected in both normal and xenografted vaginal tissues. Human markers that exhibited weak to moderate positive expression were collagen IV, laminin, fibronectin and VEGFR-3. Human elastin and human Langerhans cells exhibited strong and varying expression patterns respectively. Weak expression patterns for all murine markers were reported, with an exception of VEGFR-2 which was negatively expressed in all xenografted vaginal tissues. Significant differences (P<0.05) in the mean staining intensities between normal and xenografted vaginal tissues were reported for cytokeratin 1, fibronectin and Langerhans cells. There were no statistical differences (P>0.05) in the mean staining intensities for other markers.In conclusion, immunohistochemical studies proved that human vaginal tissue could not only survive in nude mice, but could also become active and develop structures necessary for survival, in this case, a newly formed stromal layer. The epithelium and stromal layer exhibited a human ecosystem.

Thesis (MMedSc )--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The present study investigated in particularly the specific nature of the supporting stromal layer located between the implanted human cyst and host murine tissue, which has yet to be reported. During an initial phase of this study, the particular light microscopic properties of the existing hematoxylin and eosin (H&E) stained experimental cyst was investigated, with regards to the presence or absence of specific morphological features, namely spongiosis, exocytosis, epithelial keratinization, epithelial thickness and hyperplasia, and the vascularity and fibrosis present in the stroma of these experimental sections. Subsequent analysis reported significant spongiosis, in addition to increased exocytosis of immune cells and epithelial keratinization in a number of cysts. Additionally, increased epithelial thickness and hyperplasia was reported in only 2 / 10 experimental tissues, whereas increased vascularity was observed in the stroma following analysis of H&E and Special staining, such as Verhoeff-von Gieson and Masson trichrome results. During the second phase of the study, immunohistochemical analysis with a particularly wide array of antibodies raised against specific human and mouse antigens had been applied. This involved automated immunohistochemical staining with mouse anti-human primary antibodies, in addition to manual staining with rabbit anti-mouse primary antibodies. Subsequent visualization was achieved by means of linking to biotinylated secondary antibodies, and Streptavidin-HRP incubation for standard visualization, followed by counterstaining with Hematoxylin. Maintained positive expression of cytokeratins 5, 13, and 14 was demonstrated in both control human vaginal mucosa and experimental cysts, whereas similar findings were not reported for cytokeratin 1, given the vast keratinization which was observed. Human collagen type IV and laminin of the basement membrane reported positive expression in 9 / 10 and 6 / 10 control human vaginal mucosa tissues respectively. In comparison, negative mouse collagen type IV and laminin was reported in most experimental cysts compared to positive staining in positive control mouse tissues. Immunohistochemical staining for human elastin, fibronectin, von Willebrand factor, and fibroblasts revealed maintained positive staining in all control human vaginal mucosa and experimental cysts. However, maintained expression of CD34 (endothelial marker), CD1a (langerhans cells), and human VEGFR-3 in experimental cysts was not demonstrated, compared to positive expression in control human vaginal mucosa. Subsequent analysis of murine antigens illustrated uniformly negative staining for mouse fibronectin, langerhans cells (CD207), and fibroblasts, in addition to negative staining in positive control mouse tissue sections. Furthermore, negative staining for mouse VEGFR-2 was reported in all experimental cysts; however strong positive staining of this marker in mouse kidney tissue had been reported. The findings of this study suggested that the exact nature of the stromal layer is of both human and murine origin. Furthermore, the tissue region located beneath the human vaginal epithelium is suggested to be of human nature, whereas the second distinct region located at the periphery of experimental cyst tissues, is suggested to be murine origin; however the findings of immunohistochemical analysis could not illustrate definitively the exact nature of the intermediate stromal layer, but could in fact demonstrate a mixture of human and murine tissue. / AFRIKAANSE OPSOMMING: Die huidige studie het die spesifieke molekulêre en histologiese eienskappe van die stromale laag geleë tussen menslike sist- en muis velweefsel bestudeer, wat tans nog nie bekend is nie. Gedurende die eerste fase van hierdie studie is die besondere lig-mikroskopiese eienskappe van die bestaande hematoksilien en eosien (H&E) eksperimentele siste bestudeer, met betrekking tot die aan- of afwesigheid van spesifieke morfologiese eienskappe, naamlik spongiose, eksositose van immuunselle, epiteel keratinisasie, epiteel dikte en hiperplasie, en laastens die stromale vaskulariteit en fibrose. Gevolglike analise het daarop gedui dat beduidende spongiose, eksositose en epiteel keratinisasie gevind word in die eksperimentele siste in vergelyking met kontrole vaginal weefsel. Hierteenoor is die verdikking van die epiteel en hiperplasie in slegs 2 / 10 eksperimentele siste gevind, terwyl vermeerderde vaskulariteit aangedui is na gevolglike H&E en spesiale (soos byvoorbeeld Verhoeff-von Gieson en Masson trichrome) kleuringsresultate. Die tweede fase van die studie het die immunokleuring met verskeie mens- en muis spesifieke antiliggame behels, waarby die uitdrukking van verskeie mens antigene vergelyk is met dié van muis. As sulks is ge-automatiseerde immunohistochemie toegepas met muis primêre antiliggame, tesame met fisiese kleuring met konyn primêre antiliggame toegepas. Gevolglike visualisasie is aangedui deur middel van binding met sekondêre antiliggaam en Streptavidin- HRP, gevolg deur teenkleuring met Hematoksilien. Algehele behoud van positiewe uitdrukking van sitokeratien 5, 13, en 14 is bevind, terwyl sitokeratien 1 uitdrukking nie daarwerklik vergelykbaar is met dié van kontrole mens vaginale weefsel nie. Die uitdrukking van mens kollageen IV en laminien van die basaal membraan is verder bestudeer, en het egter positiewe kleuring in 9 / 10 en 6 / 10 van kontrole mens vaginale mukosa aangedui. In vergelykking hiermee kon die huidige bevindings egter net positiewe kleuring in 4 / 10 en 3 / 10 eksperimentele siste vir kollageen IV en laminien onderskeidelik, illustreer. Immunohistochemiese analise van menslike elastien, fibronektien, von Willebrand (vW) faktor en fibroblaste het op deurgaans positiewe uitdrukking van hierdie merkers aangedui in beide eksperimentele en kontrole menslike weefsel. In teenstelling hiermee is volgehoue uitdrukking van CD34 (endoteel merker), CD1a (Langerhans sel merker) en mens VEGFR-3 in ekperimentele siste egter nie illustreerbaar nie, in vergelykking met deurgaans positiewe uitdrukking van hierdie antigene in kontrole mens vaginale mukosa. In opvolging is deurgaans negatiewe uitdrukking van muis fibronektien, langerhans sel (CD207) en fibroblaste bevestig, terwyl negatiewe kleuring ook deurgaans in positiwe kontrole muis weefsel, bekom deur die disseksie van ‘n naakte muis, gevind is. Verder is ook negatiewe kleuring vir VEGFR-2 in alle eksperimentele siste gevind, terwyl egter sterk positiewe kleuring in muis nierweefsel as positiewe weefsel gevind is. Die resultate van die huidige studie het daarop gedui dat die stromale laag onderliggend tot mens vaginale epiteel van menslike oorsprong is, terwyl die periferale stroma onderliggend tot muis velweefsel, ongetwyfeld van muis oorsprong is. Laastens kon die spesifieke oorsprong van die tussenliggende stroma nie aangedui word nie, maar dat dit moontlik uit beide menslike- en muisweefsel bestaan.