Role of aquaporin 9 in hyperglycaemia-induced testicular leydig cell apoptosis

Abstract

Hyperglycaemia is an early symptom of diabetes mellitus (DM) and hyperglycaemia-induced apoptosis is the most widely accepted cause for diabetes induced male infertility/subfertility. Aquaporin (AQP) isoforms (AQP0-12), are water channels involved in maintaining water homeostasis and regulate fluid absorption and/or excretion; thus, play a key role in reproductive function. Further, AQPs regulate diabetic complications, apoptosis induced by hyperglycaemia/high glucose (HG) and also involved in insulin regulation. Herein, we investigated AQP 9 role in hyperglycaemia-induced testicular Leydig cell apoptosis. In-vivo and in-vitro role of AQP 9 on hyperglycaemia induced Leydig cell apoptosis was analysed in diabetic rat testis and LC-540 rat Leydig cells by Real Time-PCR, western blotting and siRNA knock-down experiments. In addition, HG effect on viability and morphological changes due to apoptosis in cells were assessed by MTT and fluorescence microscopy. In-vivo and in-vitro AQP 9 expressions were increased in diabetic testicular Leydig cells. Hyperglycaemia caused apoptosis in testicular Leydig cells by increasing Cytochrome c, Bax and decreasing Bcl-2. Furthermore, AQP 9 knock-down resulted in downregulation of pro-apoptotic proteins and in contrast, upregulated anti-apoptotic protein expressions; thereby decreased apoptosis in testicular Leydig cells under hyperglycemia. Our findings collectively suggest, AQP 9 role in hyperglycaemia-induced apoptosis in testicular Leydig cells.