Objective:To investigate the effect of high glucose on intracellular cholesterol content in rat glomerular mesangial cells and the underlying mechanism.Methods:Rat glomerular mesangial cells were cultured in vitro and divided into high glucose culture group (high glucose group, medium glucose concentration of 30 mmol/L) and normal glucose culture group (normal group, medium glucose concentration of 5.5 mmol/L). Lipid content was determined by oil red O staining and spectrophotometer colorimetry at 24, 36 and 48 h of culture. Intracellular protein imprinting was used to detect the expression of low density lipoprotein cholesterol receptor (LDLR) and adenosine triphosphate binding cassette A1 (ABCA1). Results:Oil red O staining showed that the intracellular lipid drops in the high glucose group were less than those in the normal group at 36 h, and there was no significant difference between the two groups at 24 h and 48 h of culture. The total cholesterol (TC) and cholesterol ester (CE) in glomerular mesangial cells of rats in the high glucose group were significantly lower than those in the normal group ( P=0.028, 0.029), while there was no significant difference in the free cholesterol (FC) between the two groups ( P=0.306). There was no significant difference in TC, CE and FC between the two groups at 24 and 48 h of culture (all P>0.05). The expression of LDLR in mesangial cells of rats in high glucose group was significantly lower than that in normal group at 24, 36 and 48 h of culture ( P=0.043, 0.004, 0.028), and the expression of ABCA1 was significantly higher than that in normal group at 24, 36 and 48 h of culture, ( P=0.050, 0.009, 0.006). Conclusions:High glucose may reduce intracellular cholesterol content in rat glomerular mesangial cells by reducing LDLR protein expression and increasing ABCA1 protein expression.