Mitochondrial mechanism of hyperglycemia-induced apoptosis in primary mouse hepatocytes with steatosis / 中国病理生理杂志

ABSTRACT

AIM:To investigate the role of high glucose in primary hepatocytes of mice fed with a high fat di-et.METHODS:Male C57BL/6J mice were fed a high fat (45%of calories) diet ad libitum for 6 weeks to induce hepatic steatosis.Primary hepatocytes were isolated from the mouse liver by the 2 step collagenase perfusion method .The cells were incubated in low glucose ( 5 mmol/L ) , low glucose plus mannitol ( 30 mmol/L ) , or high glucose ( 35 mmol/L ) DMEM medium for 12 h.The cell viability , apoptosis , mitochondrial membrane potential , and caspase enzymatic activities were measured.Furthermore, proteins related to the stress-sensitive signaling pathway of regulating high glucose-induced apoptosis in primary hepatocytes were determined by Western blotting .RESULTS:Incubation with 35 mmol/L glucose re-sulted in a significant decrease in cell viability and an increase in apoptosis , whereas mannitol had no significant effect on the cell viability or apoptosis .A progressive depolarization of the mitochondria , an increase in cytosol cytochrome C and a dramatic decrease in mitochondrial cytochrome C in high-glucose stressed hepatocytes were observed .The enzymatic activi-ties of caspase-9 and caspase-3, but not caspase-8, were significantly increased in high glucose-stressed hepatocytes ( P<0.05).High glucose treatment suppressed the expression of Bcl-2 and Bcl-xL, while it increased the expression of the pro-apoptotic factor Bax .CONCLUSION:High glucose stress reduces mitochondrial membrane potential , initiates mitochon-dria-mediated apoptotic pathways and promotes apoptosis of hepatocytes with steatosis .This may be an important pathologi-cal mechanism of hyperglycemia-induced progression of nonalcoholic fatty liver disease .