The methanolic extract of Guibourtia tessmannii (caesalpiniaceae) and selenium modulate cytosolic calcium accumulation, apoptosis and oxidative stress in R2C tumour Leydig cells: Involvement of TRPV1 channels.

Abstract

This study evaluated the effects of the methanolic extract of Guibourtia tessmannii (GT) and selenium (Se) on cell viability, intracellular calcium concentration ([Ca2+ ]i ), apoptosis and oxidative stress through transient receptor potential vanilloid 1 (TRPV1) channel activity in CCL-97 (R2C) tumour Leydig cells. The cells were divided into nine groups and treated as follows: (a)-Control, (b)-Capsazepine (CPZ, 0.1mM, a TRPV1 channel blocker), (c)-Capsaicin (CAP, 0.01mM, a TRPV1 channel activator), (d)-GT (500μg/ml), (e)-GT+CPZ, (f)-GT+CAP, (g)-Se (200nM), (h)-Se+CPZ and (i)-Se+CAP. After treatments, cell viability, [Ca2+ ]i , apoptosis, caspase 3/9, reactive oxygen species (ROS) and mitochondrial membrane depolarisation (MMD) were evaluated. The [Ca2+ ]i , apoptosis, caspase 3/9, MMD and ROS levels were significantly (p<0.001) increased in CAP group, but lowered in CPZ group. Interestingly, these parameters were significantly (p<0.001) improved by GT and Se, compared to the CAP group. Moreover, the co-administration of GT+CAP or Se+CAP inhibited the cytotoxicity of CAP. Thus, the modulatory properties of GT and Se on Ca2+ influx, apoptosis and oxidative stress require the integrity of TRPV1 channel in CCL-97 Leydig cells. These results suggest that GT and Se might be used in the management of cytotoxicity in the testes, involving TRPV1 channel activity.