ZHOU Qiao-ling;TANG Rong;ZHU Li-li;TANG Tian-feng;TU Shan;ZHANG Yi-de
2009, 25(4): 305-312.
Objective To observe the Klotho expression in kidneys and renal tubular epithelial cells apoptosis in spontaneously hypertensive rats(SHRs) and the effects of cordyceps sinensis(CS), in order to study the mechanism of protective effects of CS on renal tubular cells apoptosis in hypertensive renal damage. Methods Twenty 22-week-old male SHRs were randomly divided into four groups: model (SHR) group, CS group (treated with CS, 5 g•kg-1•d-1), Los group (treated with losartan, 50 mg•kg-1•d-1) and CS+Los group (treated with CS 5 g•kg-1•d-1 and losartan 50 mg•kg-1•d-1). Five 22-week-old male Wistar-Kyoto rats (WKY) were used as the control group. After 8 weeks, the levels of 24 hours urinary protein (Upro), urinary N-acetyl-β-D- glucosaminidase (NAG), serum creatinine (Scr), blood urea nitrogen (BUN) and renal pathological changes were detected; the mRNA expression of Klotho, p53 and p21 was detected by RT-PCR; the protein expression of Klotho, p53, p21 and cleaved-caspase-3 was tested by Western blotting. TUNEL assay was applied to evaluate the renal tubular cell apoptosis. Results As compared to SHR group, the levels of 24 h urinary protein content [(52.16±29.3) mg, (49.97±32.5) mg, (54.67±30.09) mg vs (96.52±36.94) mg], urinary NAG[(44.13±9.11), (42.75±8.33), (41.96±7.88) U/L vs (54.07±6.57) U/L], Scr [(45.25±9.55), (43.76±8.65), (45.18±7.28) μmol/L vs (53.84±10.21) μmol/L]and BUN [(8.25±1.03), (8.40±1.58), (8.32±0.98) mmol/L vs (8.91±1.24) mmol/L]were decreased(all P<0.05), renal pathological changes were relieved, the levels of Klotho expression were up-regulated and the levels of p53 and p21 expression and cleaved-caspase-3 protein expression were down-regulated (all P<0.01), tubular cell apoptosis was decreased [7.56%±0.52%, 7.93%±0.37%, 7.37%±0.36% vs 13.32%±0.64%, P<0.01] in CS, Los and CS+Los group. Conclusions Klotho, p53 and p21 play important roles in renal tubular cells apoptosis in hypertensive renal damage. CS can up-regulate Klotho expression, down-regulate p53 and p21 expression and decrease the cleaved-caspase-3 expression and tubular cell apoptosis to ameliorate the hypertensive renal damage.