ABSTRACT
Objective To study the mechanism of overexpression of retinoic acid receptor alpha( RARα)in attenuating renal interstitial fibrosis(RIP)in rats. Methods Porty 6_week_old male SD rats were randomly divided into 4 groups:sham operation group,model group,negative control group and transfection group,with 10 rats in each group. Rats in model group were separated and double ligated with left ureter;rats in sham operation group were not li_gated with ureter;rats in transfection group and negative control group were transfected with adeno_associated virus and negative control virus carrying RARα gene on the basis of model group,respectively. All rats were sacrificed 2 weeks later. Left kidney tissues were taken for pathological examination and RIP index was calculated. The expression of colla_genⅣ(Col_Ⅳ)and fibronectin(PN)in renal tissue was detected by using immunohistochemistry. The expressions of RARα,prohibitin(DHB)and transforming growth factor_beta 1(TGP_β1)in renal tissue were detected by using real_time fluorescence quantitative polymerase chain reaction( RT _qDCR)and Western blot. Results (1)Com_pared with sham operation group,the RIP index was significantly increased in model group(22. 81 ± 2. 43 vs. 2. 34 ± 0. 55,q﹦24. 94,P〈0. 05);compared with model group,the RIP index was not of significant difference in negative control group(22. 81 ± 0. 43 vs. 22. 26 ± 3. 43,q﹦0. 67,P〉0. 05),however it significantly decreased in transfection group(14. 06 ± 2. 99 vs. 22. 81 ± 2. 43,q﹦10. 66,P〈0. 05).(2)Compared with sham operation group,the mRNA and protein expressions of RARα,DHB significantly decreased in model group,but TGP_β1 mRNA and protein,Col_Ⅳand PN protein expression significantly increased in model group( mRNA:0. 43 ± 0. 17 vs. 1. 00 ± 0. 00,0. 34 ± 0. 08 vs. 1. 00 ± 0. 00,2. 97 ± 0. 54 vs. 1. 00 ± 0. 00,all P〈0. 05;protein:0. 25 ± 0. 10 vs. 0. 51 ± 0. 06,0. 24 ± 0. 07 vs. 0. 58 ± 0. 04,0. 59 ± 0. 09 vs. 0. 33 ± 0. 06,16. 01 ± 0. 87 vs. 8. 79 ± 0. 39,14. 64 ± 0. 32 vs. 9. 36 ± 0. 59,all P〈0. 05);com_pared with model group,the mRNA and protein expressions of RARα,DHB,TGP_β1 and Col_Ⅳand PN protein ex_pression had no significant difference in negative control group(all P〉0. 05);compared with model group,the mRNA and protein expression of RARα,DHB mRNA and protein expression significantly increased,but the TGP_β1 mRNA and protein,Col_Ⅳ and PN protein expression significantly decreased in transfected group( mRNA:0. 86 ± 0. 07 vs. 0. 43 ± 0. 17,0. 89 ± 0. 11 vs. 0. 34 ± 0. 08,1. 65 ± 0. 28 vs. 2. 97 ± 0. 54,all P〈0. 05;protein:0. 40 ± 0. 07 vs. 0. 25 ± 0. 10,0. 45 ± 0. 10 vs. 0. 24 ± 0. 07,0. 43 ± 0. 08 vs. 0. 59 ± 0. 09,11. 57 ± 0. 33 vs. 16. 01 ± 0. 87,11. 67 ± 0. 53 vs. 14. 64 ± 0. 32,all P〈0. 05).(3)Correlation analysis revealed that RARα protein expression was negatively correlated with RIP index,Col_Ⅳ,PN,TGP_β1(r﹦ _0. 78,_0. 78,_0. 76,_0. 76,all P〈0. 05);DHB protein expression was negatively correlated with RIP index,Col_Ⅳ,PN,TGP _β1( r ﹦ _0. 87,_0. 87,_0. 88,_0. 75,all P 〈0. 05);RARα protein was positively correlated with DHB(r﹦0. 85,P〈0. 05). Conclusion Overexpression of RARα could attenuate RIP by enhancing DHB expression in rats subjected to unilateral ureteral obstruction.