Objective: To investigate the effects of centella asiatica (CA) granule on the expression of transform growth factor-β1(TGF-β1) and related down-stream signals in rats with early diabetic nephropathy(DN) and to clarify the molecular mechanisms of CA molecular mechanism of on preventing and curing early diabetic kidney disease DN by studying the effects of centella asiatica on TGF-β1 expression and related down-stream signals.
Methods: Sixty male SD rats were divided into control group(n=10) and DN model group(n=50). The model rats were made a right nephrectomy. One week later, diabetic nephropathy was induced by intraperitoneal injection of streptocozin(30 mg/kg) for three consecutive days. High blood glucose level of Tail vein (fasting glucose ≥ 16.7 mmol/L) and high urinary protein level(total protein level in DN group was more than twice higher than the control group) were measured to confirm early DN in rats. In the sham operation group, the right renal capsule was damaged and the corresponding amount of saline was injected. The model rats were administrated by the means of intragastric administration. The DN model group were divided into DN group, DN+fosinopril group(1.6 mg/kg·d), DN+high CA group(16.8 mg/kg·d), DN+medium CA group(11.2 mg/kg·d) and DN+low CA group(5.6 mg/kg·d), and each group was intragastric administration one time every morning last for 16 weeks. The expressions of mRNA and protein of TGF-β1, TβR1, TβR2, Smad2/3, Smad7 and the level of Smad2/3 phosphorylation were detected by using real time quantitative polymerase chain reaction and Western blot.
Results: The expressions of mRNA and protein of TGF-β1, TβR1, TβR2, Smad2/3 and the level of Smad2/3 phosphorylation were significantly increased, the expressions of mRNA and protein of Smad7 were dramatically decreased. The fosinopril and high dosage CA could reverse the effects of DN.
Conclusions: CA plays an important role in preventing and curing DN through regulating the TGF-β1/Smad signaling pathways.
Keywords: centella asiatica; diabetic nephropathy; rat; smad signaling pathway; transforming growth factor-beta 1.