ABSTRACT
Objective To investigate the mechanism of inhibitor of calpain on hyperglycemia-induced apoptosis in cultured rat cardiomyocyte.Methods Cardiomyocytes were randomly divided into three groups (control,high glucose,and ALLN).MTT assay was used to detect the viability of cultured cardiomyocytes.Laser confocal microscopy was used to observe the mitochondrial permeable transition and membrane potential.The change of Caspase-3 activity in cardiomyocytes was detected by western blot.Results MTT assay showed that,after 72 h of hyperglycemia,the viability of cardiomyocytes was significantly declined (55％ ± 11％),and the viability in the ALLN pretreatment group was (70％ ± 15％) (P ＜0.05).After hyperglycemia,the mitochondrial permeable transition of cardiomyocyte was increased (30％ ± 15％ vs 60％ ± 11％,P ＜0.05),and membrane potential was declined.Hyperglycemia could increase the expression of cleaved capsase-3,while with pretreatment of ALLN the expression of cleaved caspase-3 was downregulation(0.42 ± 0.11 vs 0.21 ±0.12,P ＜0.05).Conclusions The calpain inhibitor can protect cardiomyocytes from apoptosis under the high glucose condition.
ABSTRACT
Aim To investigate the effect of intestinal cholesterol absorption inhibitor Ezetimibe on lipid accumulation in RAW264.7 cells and identify the underlying mechanism.Method RAW264.7 cells were pretreated with the indicated concentrations of Ezetimibe (0,0.003,0.01 and 0.03 mol·L~(-1))for 24 hours or pretreated with the optimal concentration(0.03 mol·L~(-1))of Ezetimibe for different periods (0,6,12 and 24 h),followed by incubation with 50 mg·L~(-1) oxLDL for 24 hours,then the number of intracellular lipid droplets and lipid content were measured by using oil red O staining and HPLC; the expression of NPC1L1 was measured by Western blot.Results Pretreatment with indicated concentrations of Ezetimibe caused a concentration-dependent inhibition of intracellular lipid accumulation;pretreatment with 0.03 mol·L~(-1) Ezetimibe caused a time-dependent inhibition of intracellular lipid accumulation.It was noted that pretreatment with 0.03 mol·L~(-1) Ezetimibe for 24 hours inhibited CE by about 47%+0.1% compared with control group(oxLDL alone).Immunoblotting results showed that NPC1L1 was expressed in RAW264.7 cells and it was down-regulated after Ezetimibe treatment.Conclusions Ezetimibe causes concentration-dependent and time-dependent inhibition of lipid accumulation in RAW264.7 cells;it also reduces NPC1L1 expression in RAW264.7 cells.