Histological and ultrastructural studies of female reproductive vasculature of one humped camel in relation to possible thermoregulation and ovarian hormones

The study was designed to explore anatomical and histological vasculature changes in the female genital system of camel and serological aspects that might be responsible to maintain thermoregulation. Twenty-four adult female camels were sampled during breeding (November-April) and non-breeding (May-October) season. Blood was collected for estrogen, progesterone and cortisol level estimation. Genital organs were sampled and described after slaughtering. Samples were taken from the ovarian artery (OA), vein (OV) and arterio-venous complex (AVC), for light and scanning electron microscopy. Sections were stained with Hematoxylin and Eosin. (H&E), Masson’s trichrome, Weigert’s elastic and toluidine blue. Temperature and relative humidity were used to calculate stress indicator. Stress indicator was higher in non-breeding season (NBS). Anatomical and histological vasculature (OA, OV, AVC) dynamics were significantly higher in breeding season (BS) especially diameter of left OA. Parameters of OA were positively associated with estrogen level. Collagen, elastic, smooth muscles and mast cells were recorded least in BS compared to NBS. Unique venous structure, intra-mural venules (IMV), was discovered in tunica intima of OA, seen positively and negatively associated with estrogen and cortisol level in BS, respectively. Scanned electron-micrograph exhibited penetration and wrapping of OA by small thinned-walled venules that may form IMV. The AVC was too tightly packed to differentiate due to the collapse of the wall. Hormonal, seasonal, stress indicator and vascular dynamic of female genital system are interlinked and IMV in association with OA and OV may be proposed as the site of counter-current exchange in female reproductive system of the camel.