WNKs Regulating The NCC Expression In Tubular Epithelium Of Rat With Chronic Renal Failure

Objects:Chronic renal failure (CRF) is a gradual loss of the ability of the kidneys, is characterized by progressive and irreversible loss of large numbers of functioning nephrons. The residual nephrons is no longer able to excrete wastes, concentrate urine, and conserve electrolytes, then leads to water, electrolyte, acid-base imbalance, metabolites accumulation, and endocrine dysfunction. WNKs is a serine/threonine kinase, which plays an important role in maintaining electrolyte balance through regulating the activity of various ion channels and transporters in renal tubular cells. In order to discussing the role WNKs and NCC in the regulation of electrolyte balance and the progression of chronic renal diseases, the rat model of chronic renal failure was estabolished, WNK3, WNK4, WNK1, NCC, AT1mRNA and protein expression were determined.Methods:The rat model with chronic renal failure was estabolished with adriamycin, albumin and both adriamycin/albumin respectively. The body weight of rats was recorded once every three days and the urine volume of rats was recorded weekly. The renal pathological changes was observed by HE staining, the mRNA of WNK3, WNK4, WNK1and NCC was detected by RT-PCR, and the protein expression of WNK3, NCC, and AT1was detected by Western blotting, the WNK3, WNK4expression was also anlysed with the immunohistochemical method.Results:The results of HE staining showed that renal glomerulus was atrophy obviously, and it was also showed that fibrosis of bowman’s capsule and cast in the tubular lumen in the experimental groups. The level of WNK4mRNA in the experimental groups was significantly lower than that in the control group. The level of WNK3mRNA was higher significantly in B group and AB group when compared with that in the control group, but that in Agroup was increased slightly. There is no change of WNK1mRNA level in B group and AB group, but it decreased slightly in the A group when compared with that in the control group. The level of NCC mRNA was increased significantly in B group and AB group when compared with that in the control group. The expression of WNK3, NCC protein was elevated in the experimental groups when compared with that in the control group, they increased more significantly in AB group. The expression of AT1protein elevated in the all experimental groups when compared with that in the control group.Conclusions:1. Intraperitoneal injection of doxorubicin combined albumin can successfully induced the renal failure in the rat.2. the upregulated WNK3, NCC, downregulated WNK4in the rat of chronic renal failure induced with adriamycin and overload protein indicates that WNK3, WNK4participates in the development and progression of chronic renal injury by regulating the NCC activity, the expression and activity of NCC was determined by the ratio of WNK3and WNK4.