Effects of Tianqi Jiangtang capsule on renal function in rats with diabetic kidney disease

Abstract

Objective To explore the protective effect of Tianqi Jiangtang capsule on kidney in rats with diabetic kidney disease (DKD) and its mechanisms. Methods A total of 60 eight-weeks old male SD rats were randomly and equally divided into 6 groups: control group (normal group), DKD model group (DKD group), irbesartan group [20 mg/(kg·d)], low-dose Tianqi group [0.32 g/(kg·d)], mid-dose Tianqi group [0.64 g/(kg·d)] and high-dose Tianqi group [1.28 g/(kg·d)]. DKD rat model was established by single-dose intraperitoneal injection of streptozotocin (35 mg/kg). The experimental group rats were fed with irbesartan and different doses of Tianqi Jiangtang capsule, the model group rats with normal saline. Weight, plasma glucose and lipids, 24-hour urine and serum sample was collected to detect urinary microalbumin and transforming growth factor-β1 (TGF-β1) after twelve weeks. Kidney tissues of all the rats were collected. One kidney was used for morphological examination, and the other one was homogenized for measurement of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. Variance analysis(ANOVA), least-significant difference(LSD) and multiple comparison correction (Bonferroni correction) were used for statistical analysis. Results Compared with DKD group, the level of fasting plasma glucose [(23.8±3.5) vs (29.4±3.3) mmol/L], total cholesterol [(1.67±0.32) vs (2.40±0.19) mmol/L] and triglyceride [(1.62±0.25) vs (2.76±0.64) mmol/L], 24 h urine microalbumin[(1 411±156) vs (2 018±259) μg/24 h] and serum TGF-β1 level [(333±46) vs (650±64) μg/ml] were decreased in high dose of Tianqi group (all P<0.05). Level of SOD [(402±22) vs (223±32) U/ml] and GSH-Px activities [(1 633±37) vs (1 181±53) U/ml] were significantly increased (all P<0.05), similar to the irbesartan group, even better. Compared with DKD group, there was no thickening of glomerular basement membrane in high dose of Tianqi group. Mesangial cells, extracellular matrix was decreased, and less edema in the epithelial cells of renal tubule. Conclusions High dose of Tianqi Jiangtang capsule can ameliorate levels of blood glucose and blood lipid, decrease urine microalbumin in DKD rats and improve the renal fibrosis, thus possibly delaying the progress of DKD. The mechanism is probably related to the increase of antioxidant and anti-fibrosis function of the kidney. Key words: Diabetic kidney disease; Albuminuria; Oxidative stress; Tianqi Jiangtang capsule; Renal fibrosis