The microvascular architecture of the rat vagina revealed by image analysis of vascular corrosion casts

Background: Female sexual dysfunction is a common but poorly understood hum an condition. One of the aspects hindering progress in this area is the lac k of appropriate animal models that can be used to study the complex factor s involved in this sexual health problem. Recently, attention has focused o n the probable role of vascular dynamics of the genital organs and their po tential for impact on female sexuality. The objective of this study was to provide a better description of the vascular anatomy of the female rat vagi na and external genital organs in an attempt to better develop this as an a nimal model to study female sexual dysfunction. Methods: Young female (nonestrous) virgin rats were anesthetized, the abdom inal aorta was cannulated, and the distal vasculature was flushed and fixed in vivo for histological studies or for subsequent infusion with Mercer re sin for vascular corrosion casting. Vascular corrosion casts of the externa l genitalia (vagina and vulva) were studied using a scanning electron micro scope (SEM), Fixed tissue specimens were also embedded and sectioned for hi stochemical and immunohistochemical analysis. Results: Scanning electron microscopy imaging allowed a description of the vascular and microvascular system of the nonestrous female rat genitalia. M ajor feeding vessels were located laterally in the muscular and serosal lay ers of the vagina with a complex system of interanastomosing collaterals be tween these large lateral trunks. The sub-epithelial region of the vaginal wall contains a dense and rich network of capillaries that perfuse the epit helium. These data were corroborated by two- dimensional histochemistry and immunostaining for endothelial and smooth muscle cells on paraffin-embedde d thin sections of the female vagina and vulva. Conclusion: This study provides the first detailed three-dimensional en blo c view of the macro- and microvascular anatomy of the female rat vagina and vulva. The findings suggest an active interaction between the microvascula ture and the epithelial cells of the vaginal wall. This study will provide the basic anatomic groundwork for future experiments on perturbations of th e vascular system of the rat female genitalia in response to hormonal stimu li and various disease states.