Aim To investigate the effects of high glucose on the metabolic mechanism of lipid in cultured rat cardiomyocytes. Methods The model of insulin-resistant cardiomyocytes were established,incubated with the intervening factors of insulin and high glucose of different concentration.The changes of lipid metabolism of cardiomyocytes were observed surrounding the center of lipoprotein lipase(LPL)as the important enzyme of lipid metabolism.The pathologic damnification of cell-structure were observed through transmission electricmicroscope. Results The expression of LPL mRNA of the insulin-resistant cardiomyocytes which treated with 80 mmol/L glucose was obviously increased(p<0.05).After incubated with 10~(-8) mol/L insulin,the expression of LPL mRNA of those cardiomyocytes was decreased;the activity of LPL of the insulin-resistant cardiomyocytes was obviously enhanced(p<0.05)under the same concentration of glucose.After incubated with 10~(-8) mol/L insulin,the activity of LPL was weakened;the activity of LPL of the cardiomyocytes in the same incubated condition was not significantly different(p<0.05) treated with 20 and 80 mmol/L glucose;the concentration of lipid of the insulin-resistant cardiomyocytes was obviously enhanced(p<0.05)under the same concentration of glucose.After incubated with 10~(-8) mol/L insulin,the concentration of lipid was weakened;the concentration of lipid of the cardiomyocytes in the same incubated condition was not significantly different(p<0.05) treated with 20 and 80 mmol/L glucose.Swelled mitochondria,formed myelir figure,increased lipid drops were observed through transmission electricmicroscope in normal cardiomyocytes and the insulin-resistant cardiomyocytes.After adding 10~(-8) mol/L insulin,there were no swelled Mitochondria or myelir figure,with little lipid drops in the cardiomyocytes. Conclusions High glucose could increase the expression of LPL mRNA and the lipid in cultured rat cardiomyocytes.Insulin could reverse these changes,which may have implication for diabetes mellitus and its complications.