Effects of L-arginine on proliferation of human renal mesangial cells and production of extracellular matrix

AIM: To investigate the effect of L-arginine (L-arg) on the proliferation o f human mesangial cells and production of collagen. METHODS: The influence of L-arg on the cell proliferation was determined by MTT assay, immunocytoc hemical detection of expression of proliferative cell nuclear antigen ( PCN A), and flow cytometrical analysis of cell cycle. Procollagen III and total collagen level in the supernatant and expression of collagen Rr mRNA in hu man mesangial cells were determined by radioimmunoassay, hydroxyproline col orimetric assay, and reverse transcription polymerase chain reaction (RT-PC R). RESULTS: L-Arg induced inhibition of human mesangial cell lines (HMCL) in a concentration-and time-dependent manner. Immunocytochemical study for PCNA showed the number of cells was decreased, though the percentage of PCN A positive cells was increased in L-arg-treated group. Flow cytometrical an alysis showed that cells in S and G(2)-M phases were markedly increased in L-arg-treated group compared with those in control group. Furthermore, L-ar g significantly inhibited the production of procollagen III and total colla gen in the supernatants determined by radioimmunoassay and hydroxyproline c olorimetric assay (P < 0.05 and 0.01, respectively) and inhibited the expre ssion of collagen IV mRNA determined by RT-PCR (P < 0.01). CONCLUSION: L-ar g could exert an inhibitory effect on the proliferation of human mesangial cells and production of extracellular components, which strongly suggested its potential therapeutic role in the chronic renal scarring.