| OBJECTIVE To investigate the expression and the role of retinoic acid receptors (RARs) in renal tissue of rats with unilateral ureteral obstruction (UUO).METHODS Eighty Wistar male rats (6-weeks-old) were randomly assigned into2groups:sham-operated group (n=40) and model group (n=40). The left ureter of rats in mode group were dissociated to be obstructed. The rats in sham-operated group were dissociated left ureter only, and not to be obstructed. Twenty rats of both two groups were killed on the end of2-week and4-week after surgery respectively. Histological changes of renal tubular interstitium were observed by Masson and HE staining, and the index of renal interstial fibrosis (RIF) was calculated. The mRNA and protein expressions of RARα, RARβ, RARγ and transforming growth factor-β1(TGF-β1) were detected by realtime reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry, and western-blot. The expression of protein of collagen-Ⅳ (Col-Ⅳ) and fibronectin (FN) were detected by immunohistochemistry and western-blot.RESULTS (1) Compared to sham-operated group, in model group①Histological changes showed that there was more collagen deposition, fibroblast proliferation and diffused lymphoeytein filtration in the renal interstitium, and the index of RIF was increased remarkably in model group (P<0.01), and it was increased accompanying with the degree of obstruction;②The expressions of mRNA and protein of RARα and RARβ were decreased significantly in model group (P<0.01), and it was decreased accompanying with the degree of obstruction. The mRNA and protein expressions of RARy were no significantly in model group (P>0.05);③The mRNA and protein expressions of TGF-β1were increased remarkably(P<0.01), and it was increased accompanying with the degree of obstruction;④The protein expressions of Col-Ⅳ and FN were increased significantly (P<0.01), and it was increased accompanying with the degree of obstruction.(2) Correlation analysis showed that: the protein expression of RARa in model group was negtively correlated with the index of RIF, TGF-β1,Col-Ⅳand FN (r=-0.833,-0.763,-0.825,-0.918; P<0.01); the protein expression of RARβ in model group was negtively correlated with the index of RIF, TGF-β1, Col-Ⅳand FN (r=-0.728,-0.736,-0.818,-0.784; P<0.01).The protein expression of TGF-β1, Col-Ⅳor FN were positive correlations with the index of RIF (r=0.995,0.977,0.969; P<0.01); the protein expression of RARy in model group had no correlation with the index of RIF, TGF-β1, Col-Ⅳand FN(r=0.145,0.261,0.126,0.225; P>0.05).CONCLUSION The mRNA and protein expressions of RARa and RARβ were decreased significantly in renal tissues of rats with UUO, and they were decreased remarkably accompanying with the degree of obstruction. RARa and RARβ might be involved in the progression of RIF. Part ⅡThe association and effect of PPARγ/RARs signaling pathway on the renal interstitial fibrosisin in rats with unilateral ureteral obstructionOBJECTIVE To explore the association and effect of PPARγ/RARs signaling pathway on the RIF in rats with UUO.METHODS160Wistar male rats (6-weeks-old) were randomly divided into4groups:model group (n=40), PPARγ receptor agonist group (n=40), PPARγ receptor blocker group (n=40), DMSO group (n=40). The left ureter of all rats were dissociated to be obstructed after anesthesia. After postoperative three days, three groups were given daily intraperitoneal injection of medication:the PPARγ receptor agonist group with rosiglitazone Sodium (0.3mg/kg.d), PPARγ receptor blocker group with GW9662(0.3mg/kg.d), DMSO group with DMSO (0.6ml/kg.d). Twenty rats of4groups were killed on2,4weeks after surgery respectively. Histological changes of renal tubular interstitium were observed by HE and Masson staining, and the index of RIF was calculated. The mRNA and protein expressions of PPARγ, RARα, RARβ, RARγ and TGF-β1were detected by immunohistochemistry, western-blot and RT-PCR. The protein expressions of Col-Ⅳ and FN were detected by immunohistochemistry and western-blot.RESULTS (1) Compared to model group:①in rosiglitazone Sodium group, the severity of interstitial fibrosis was alleviated significantly, and the index of RIF was decreased remarkably (P0<0.01); the mRNA and protein expressions of renal PPARγ and RARα were increased remarkably (P<0.01); the mRNA and protein expressions of TGF-β1were decreased significantly than those in model group (P<0.01); the protein expressions of renal Col-Ⅳ and FN were decreased remarkly (P<0.01); the expressions of renal RARβ and RARy were no significant change (P>0.05).②n GW9662group, the severity of interstitial fibrosis was increased significantly, and the index of RIF was increased remarkably (P<0.01); the mRNA and protein expressions of renal PPARy and RARa were increased remarkably (P<0.01); the mRNA and protein expressions of TGF-β1were increased significantly than those in model group (P<.01); the protein expressions of renal Col-Ⅳ and FN were increased remarkly (P<0.01); the expressions of renal RARβ and RARy were no significant change (P>0.05).③In DMSO group, the expression of various indicators was no significant difference (P>0.05).(2) Correlation analysis showed that:the protein expression of PPARy was significant positive correlation with the index of RARa (r=0.883; P<0.01); the protein expression of PPARy was no correlation with the index of RARβ and RARγ (r=0.132,0.231; P>0.05); the protein expression of PPARy was negtive correlation with the index of RIF, TGF-β1, Col-Ⅳand FN (r=-0.932,-0.875,-0.917,-0.875; P<0.01); the protein expression of RARα was negtive correlation with the index of RIF, TGF-β1, Col-Ⅳ and FN (r=-0.887,-0.823,-0.886,-0.903; P<0.01).CONCLUSION The PPARγ/RARα signaling pathways might be involved the progression of RIF in UUO rats. The PPARγ receptor agonist may alleviate the RIF lesion by signaling pathway of PPARγ/RARα. |
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