Aim To detect the expression of lectin-like oxidized low-density lipoprotein receptor-1(LOX-1) on aorta in diabetic rats and to observe the effects of telmisartan in order to investigate the mechanisms of marcrovascular disease in diabetes.Methods A total number of 32 male 6 weeks of age Sprague Dawley rats were divided into two groups,including control group(n=8) and experimental group(n=24).The latter group of rats was fed with high fat and sugar diet for 4 weeks and then was made into diabetic model by intraperitoneal injection of streptozotocin once at a dose of 45 mg/kg.The diabetic rats were further divided into diabetic mellitus group(n=9)(DM group),telmisartan group(n=11) which was given 20 mg/kg weight telmisartan,control group and DM group rats received distilled water.All groups of rats were given medicines by using oral gavage for 8 weeks.The serum lipid parameters were determined by routine methods using a fully automatic biochemical analyzer.Aorta paraffin sections were performed HE stain to observe atherosclerotic lesion.Expression of LOX-1 mRNA were detected by real-time PCR and Western blot was used to quantify their protein expression.Results No significant difference was found among three groups on the serum levels of total cholesterol(TC)(P=0.13) and triglyceride(TG)(P=0.35).High density lipoprotein(HDL)(0.99±0.12 mmol/L vs 1.37±0.23 mmol/L) was decreased(P=0.001) and low density lipoprotein(LDL)(0.48±0.08 mmol/L vs 0.34±0.03 mmol/L) was increased(P=0.001) in DM group compared with the control.Histology of rat aorta showed in control group the intima was thin and smooth,endothelial cells lined,while in DM group the intima was thicken in local lesion and it did not attenuate after treatment of telmisartan compared with DM group.No obvious atherosclerotic plaque was found in the three groups.In DM group,LOX-1 mRNA(0.316±0.055 vs 0.154±0.029) and protein expression(1.271±0.238 vs 0.739±0.113) were significantly upregulated compared with the control(P=0.000) while they(0.192±0.030 vs 0.316±0.055 and 0.691±0.198 vs 1.271±0.238) were downregulated in telmisartan group compared with the DM group(P=0.000).Conclusion LOX-1 mRNA and protein expression were increased in aorta of diabetic rats.Telmisartan may downregulate LOX-1 expression in diabetic rats.