The effect of L-arginine on the progression of chronic renal scarring in remnant kidney

摘要

Objective To investigate the effect of L-arginine (L-arg) on early compensatory renal growth (CRG), tubulointerstitial accumulation of extracellular matrix (ECM), long term survival rate and renal scarring in rats with 5/6 nephrectomy (SNx). Methods The experiment included four groups of rats (n = 5 each group): (1) Sham group, (2) SNx group, (3) SNx + L-arg group, and (4) Sham + L-arg group (L-arg 1% in drinking water). Parameters related with CRG and early tubulointerstitial expression of ECM and αsmooth muscle actin (αSMA) were evaluated by immunohistochemistry at day 30. The survival rate and the extent of renal scarring in the rats were observed at day 120. Results L-arg significantly increased the early CRG of SNx rats as determined by the wet kidney weight (P<0.05), total protein (P<0.01), and DMA content (P< 0.001) of the remnant kidney. The cell proliferation in the tubulointerstitium as determined by immunostaining for proliferative cell nuclear antigen (PCNA) also markedly increased (P < 0.05). Furthermore, glomerular volume (Vg) in the SNx rats treated by L-arg increased 16% compared with that in the SNx group (P = 0.06). More specifically, L-arg significantly increased the interstitial immunostaining for collagen Ⅲ, Ⅳ, and fibronectin (P<0.05, 0.01, respectively), which were positively correlated with the increased expression of α-SMA (P < 0.001, respectively). In the long term experiment, L-arg significantly reduced the survival rate (P<0.05) and increased the severity of renal scarring in the SNx rats (P<0.05). Conclusion This preliminary study suggested that early supplementation with L-arg might exacerbate the progression of renal scarring in rat remnant kidney.