Abstract: Objective To observe the effect of exenatide on endoplasmic reticulum stress (ERS) in human renal mesangial cells (HRMCs) injured by fluctuating hyperglycemia culture, and to explore the mechanism. Methods HRMCs were randomly divided into three groups: control group (group N, cells were cultured in 5.6 mmol/L glucose for 24 h),fluctuating hyperglycemia group (group F, cells were cultured in 30 mmol/L glucose for 3 h, 5.6 mmol/L glucose for 2 h,repeated three times in one day, then 5.6 mmol/L glucose overnight), fluctuating hyperglycemia and exenatide group (group F+G, HRMCs were cultured in fluctuating hyperglycemia and 100 nmol/L exenatide). MTT assay was used to measure the viability in each group. The apoptosis rates were detected by flow cytometry in three groups. The relative expression of glucose regulated protein78 (GRP78) and CCAAT/enhancerbinding protein homologous protein (CHOP) were tested by Western blot assay. Results Compared with the group N, the cell proliferation level decreased, the cell apoptosis rate increased, and the expression levels of GRP78 and CHOP increased in F group (P < 0.05). After treatment with exenatide,the cell proliferation rate increased, cell apoptosis rate decreased (P < 0.05), and the expression levels of GRP78 and CHOP decreased in F+G group, compared with those of the group F (P < 0.05). Conclusion Exenatide can reduce the damage of fluctuating hyperglycemia on HRMCs by down-regulating the stress levels of the endoplasmic reticulum stress.

Key words: mesangial cells, cell proliferation, apoptosis, endoplasmic reticulum stress, fluctuating hyperglycemia, exenatide