ObjectiveTo observe the effects of Tongluo recipe on the renal expression of connective tissue growth factor(CTGF), advanced glycation end products receptor(RAGE) and phosphorylated extracellular signal regulated kinase(p-ERK1/2) in streptozotocin-induced rat model of type 1 diabetes mellitus, and to explore the mechanism of its renoprotective effect. MethodsAdult male Sprague-Dawley rats, weighing 180-220 g, were randomly divided into 2 groups: control group (A, n=10) and model group (n=50). Rat diabetic model was induced by intraperitoneal injection of streptozotocin (60 mg/kg body weight), and the model rats were randomly subdivided into B group (diabetic control, n=10),C group(diabetic rats treated with low dose of Tongluo recipe,0.5 g·kg-1·d-1, n=10), D group (diabetic rats treated with medium dose of Tongluo recipe, 1.0 g·kg-1·d-1, n=10), E group (diabetic rats treated with high dose of Tongluo recipe, 2.0 g·kg-1·d-1, n=10), and F group (diabetic rats treated with losartan, 30 g·kg-1·d-1, n=10). At the end of the 12th week the rats were sacrificed and were weighed; the urea nitrogen (BUN) in blood, serum creatinine (Scr), 24 h albumin excretion rate(UPRO24), microalbuminuria(MAU) and creatinine in urine(Ucr) were analyzed by bio-chemical methods. The left kidneys were weighed and the right kidneys were subjected to real-time PCR analysis for the expression of CTGF and RAGE mRNA. Western blotting analysis was used to examine the expression of CTGF, RAGE, p-ERK1/2, and total-ERK1/2 protein expression. ResultsThe creatinine clearance rate, urea nitrogen, 24 h albumin excretion rate, and microalbuminuria in group D and E were significantly lower than those of group B. And the renal functions of rats in group D and E were improved and the expression of RAGE and CTGF mRNA and protein and p-ERK1/2 protein expression was significantly decreased (P<0.05). ConclusionTongluo recipe may exert its renoprotective effect through inhibiting RAGE-ERK1/2-CTGF signal pathway.