Expression of c-met in human kidney fibroblasts induced by high glucose in vitro and the regulation of Radix Astragali

OBJECTIVE: To investigate the effect of high glucose on the expression of c-met in human kidney fibroblasts in vitro, and to explore the regulation of Radix Astragali. METHODS: A cell culture system of human kidney fibroblasts was developed in vitro. The human kidney fibroblasts were divided into normal control group, high glucose group and mannitol group. Expressions of c-met and transforming growth factor-beta1 (TGF-beta1) mRNAs were detected by reverse transcription polymerase chain reaction (RT-PCR) and the expressions of c-met protein were analyzed by Western blot method after 6-, 12-, 24-, 48- and 96-hour culture. The human kidney fibroblasts were also cultured with 10% Radix Astragali containing serum; the expressions of c-met mRNA and protein were detected after 24- and 48-hour culture. RESULTS: Compared with the normal control group, expression of c-met mRNA in the high glucose group was significantly increased after 12-hour culture (P<0.05), arriving at the peak after 24-hour culture (P<0.01). The level of TGF-beta1 mRNA was higher in the high glucose group than that in the normal control group after 24-hour culture (P<0.05), arriving at the peak after 96-hour culture (P<0.01). Forty-eight hours after treating with 10% Radix Astragali containing serum, the levels of c-met mRNA and protein in fibroblasts were increased, and were higher than those in the high glucose group (P<0.01, P<0.05). CONCLUSION: High glucose can induce the expressions of c-met mRNA and protein in earlier period, and then inhibit the expressions. Radix Astragali can up-regulate the expressions of c-met mRNA and protein of human kidney fibroblasts, which may be one of its action mechanisms in delaying the progression of diabetic nephropathy.