Effect of caveolin-1 on renal injury and the expression of tight junction protein in MRL/lpr mice kidney

Abstract

Objective To study the effect of caveolin-1 on renal injury and the expression of tight junction proteins in MRL/lpr mice kidney. Methods The mice were divided into 4 groups: 5 mice in the normal control group (BALB/c mice); the MRL/lpr lupus mice (n=18) were randomly divided into the MRL/lpr group in which 6 mice were included; the negative control group in which 6 mice were included; the caveolin-1 transfection group in which 6 mice were included. The changes of urine protein, the levels of urea (BUN) and creatinine (Cr) were detected. The expressions of claudin-5, occludin, ZO-1 and caveolin-1 protein were determined by western bloting. Analysis of variance was used to determine statistical significant differences between the two groups. A significance level of 0.05 was considered as signigicant. Results Compared with the control group, 24 h urine protein [(2 894±437) mg, (412±72) mg], BUN [(8.7±1.5) mmol/L, (6.9±0.4) mmol/L], Cr [(106±22) μmol/L, (85±4) μmol/L] were significantly increased, level of caveolin-1 protein increased (265±17, 61±6), the level of occludin (114±12, 190±12), claudin-5 (60±5, 80±6) and ZO-1 (98±11, 206±15) protein decreased in the MRL/lpr group (P<0.05). After caveolin-1 transfection, the levels of urinary protein [(1 253±249) mg, (2 894±437) mg], BUN [(6.5±1.3) mmol/L, (8.7±1.5) mmol/L], Cr [(78±17) μmol/L, (106±22) μmol/L] were significantly decreased, and the levels of occludin (218±16, 114±12), claudin-5 (87±6, 60±5) ZO-1 (313±17, 98±11) were increased (P<0.05). Conclusion The expression of caveolin-1 protein in the renal tissues of lupus nephritis increases. Caveolin-1 can reduce the expression of tight junction proteins and contribute to progres-sion of lupus nephritis. Key words: Lupus nephritis; Caveolin 1; Claudins