A Novel Role for the Calcium Sensing Receptor in Rat Diabetic Encephalopathy

作者:Dong Shiyun; Li Gang; Zheng Dan; Wu Jichao; Sun Dianjun; Yang Fan; Yu Xiangjing; Li Ting; Sun Aili; Liu Jiaqi; Zhong Xin; Xu Changqing; Lu Fanghao; Zhang Weihua*
来源:Cellular Physiology and Biochemistry, 2015, 35(1): 38-50.
DOI:10.1159/000369673

摘要

Background: Diabetic encephalopathy is a common complication of diabetes, and it may be involved in altering intracellular calcium concentrations ([Ca2+](i)) at its onset. The calcium sensing receptor (CaSR) is a G-protein coupled receptor, however, the functional involvement of CaSR in diabetic encephalopathy remains unclear. Methods: In this study, diabetic rats were modeled by STZ (50 mg/kg). At the end of 4, 8 and 12 weeks, the CaSR expression in hippocampus was analyzed by Western blot. In neonatal rat hippocampal neurons, the [Ca2+](i) was detected by laser scanning confocal microscopy, the production of reactive oxygen species (ROS) in mitochondria, the level of NO and the mitochondrial transmembrane potential were measured by MitoSOX, DAF-FM and JC-1, respectively. Results: Our results showed in hippocampal neurons treated with high glucose, CaSR regulated [Ca2+](i) through the PLC-IP3 pathway. CaSR expression was decreased and was involved in the changes in [Ca2+](i). Mitochondrial membrane potential, NO release and expression of p-eNOS decreased, while the production of ROS in mitochondria increased. Conclusion: Down-regulation of CaSR expression was accompanied by neuronal injury, calcium disturbance, increased ROS production and decreased release of NO. Up-regulation of CaSR expression attenuated these changes through a positive compensatory protective mechanism to inhibit and delay diabetic encephalopathy in rats.