Effect of salvianolic acid B on high-glucose induced renal tubular epithelial-mesenchymal transition in rats and its mechanism

Abstract

The aim of this paper was to observe the effect of salvianolic acid B(Sal B) on high-glucose induced renal tubular epithelial-mesenchymal transition(EMT) in rats, and to explore its possible mechanisms of prevention and treatment of diabetic nephropathy. The rat renal tubular epithelial NRK-52 E cells were cultured in vitro. The cells were divided into control group, high glucose group, high glucose+10 μmol·L~(-1)Sal B group(Sal B), the above 3 groups were set at 6, 12, 24 and 48 h for dynamic observation; high glucose+Sal B different concentration(1, 5, 10 μmol·L~(-1)) groups, high glucose+5.0 μmol·L~(-1) pioglitazone group, high glucose+10 μmol·L~(-1)Sal B+5 μmol·L~(-1)GW9662 group. The protein expression levels of PPARγ, PTEN, α-SMA, E-cadherin and PI3 K/Akt signaling molecules were determined by Western blot. The mRNA expression of PPARγ and PTEN were detected by Real-time PCR. The viabi-lity of NRK52 E cells was determined by MTT assay. The results showed that as compared with control group, the mRNA and protein expression levels of PPARγ and PTEN in high glucose group gradually reduced, the protein expression levels of α-SMA and p-Akt~((Thr308))gradually increased, and the protein expression of E-cadherin gradually reduced(P<0.05). As compared with high glucose group, when increases in Sal B doses, the mRNA and protein expression levels of PPARγ, PTEN in high glucose + different concentrations of Sal B groups gradually increased, the protein expression levels of α-SMA and p-Akt~((Thr308)) gradually reduced, and the protein expression of E-cadherin gradually increased(P<0.05), however, the effect of 1 μmol·L~(-1)concentration of Sal B on the expression of PPARγ mRNA and protein and PTEN mRNA was not significantly different. As compared with high glucose group, the mRNA and protein expression levels of PPARγ mRNA(except 6 h) and protein(except 6 h), PTEN mRNA(except 6 h) and protein(except 6, 12 h) kept increasing, the protein expression levels of α-SMA and p-Akt~((Thr308))(except 6 h) continued to reduce, the protein expression of E-cadherin kept increasing in high glucose+10 μmol·L~(-1) Sal B dynamic observation group(P<0.05). As compared with high glucose group, Sal B and the pioglitazone(PIO) can greatly enhance the expression of PPARγ, PTEN at mRNA and protein levels, enhance the expression of E-cadherin at protein levels, and reduce the expression of α-SMA, p-Akt~((Thr308))protein level(P<0.05), there was no significant difference between the two groups. However, the expression levels of PPARγ and PTEN mRNA and protein, E-cadherin, α-SMA and p-Akt(Thr308) protein in the Sal B+GW9662 control group were not statistically significant compared with the high glucose group. The effect of Sal B was blocked by the PPARγ antagonist GW9662. It can be concluded that Sal B can suppress the NRK52 E cells induced by high-glucose EMT. The mechanism may be related to the activation of PPARγ with Sal B, and the up-regulation of PTEN expression, and thereby inhibiting the fibrosis effect of PI3 K/Akt signaling pathway.