Exploring the Nexus of Steroidal Hormone Receptor, Uterine <scp>VEGF</scp> Expression and <scp>NADPH</scp>‐d Interaction in Buffalo Uterus During Oestrous Cycle With Seasonal Variation

The reproductive efficiency in buffalo is highly influenced by seasonal variability. Angiogenesis in the reproductive cycle is important for optimal physiological functioning of uterus. Estrogen receptor-α (ERα), vascular endothelial growth factor (VEGF) and reduced nicotinamide adenine dinucleotide phosphatase diaphorase (NADPH-d) are vital indicators for the uterine angiogenic process. This study was conducted to see the effect of season on the expression of different uterine angiogenic factors. Season wise (winter and summer) and phase wise (follicular and luteal), immune staining intensity of buffalo uterus was measured by calculating the optical density value (OD) for ERα and VEGF. Percentage of immuno-positive cell count for ERα was done. Histoenzymic NADPH-d expression was analysed. Expression of all these factors increased during follicular phase of oestrous cycle in order to support the angiogenesis; however, the expression was significantly lower (p ≤ 0.05) in term of OD value as well as percentage count of immuno-positive cells during summer season indicating lower angiogenic activity that subsequently affected reproduction in buffalo.