Retinoic acid (RA) receptor, is a group of ligand-regulated nuclear transcription factors and widely distributed in various tissue cells. The different subtypes of RA receptor can polymerize into homologous or heterogenous dimmers, and then participate in the physiological and pathological processes of embryonic development, cell proliferation and differentiation, and apoptosis. However, the relationship between the expression of RA receptor and the diseases is different in diverse cells or tissues. Recent researches demonstrated that RA receptor is closely related to the pathogenesis and development of renal diseases. This article aims to review the role of the RA receptor and its signal pathway in the development of renal diseases.

Objective To investigate the effect of all-trans retinoic acid (ATRA) on transforming growth factor β1 (TGF-β1)/Notch signaling pathway in injured podocytes induced by adriamycin (ADR) in vitro.Methods Podocytes cultured in vitro were randomly divided into normal group,model group,ATRA treatment control group,12-hour ATRA intervention group and 24-hour ATRA intervention group.Morphological changes were observed by using light microscope.The expressions of TGF-β1,podocin,Notch 1,Jagged 1 mRNA were evaluated through real-time polymerase chain reaction (RT-PCR) and the corresponding proteins were detected by using Western blot.Results (1) No obvious changes between normal group and ATRA treatment control group were revealed as the plump podocytes and distinct outline were found in light microscope,while podocytes in model group showed disordered arrangement,fuzzy boundary,atrophy,hypertrophy and increased cellular debris.Of note,the podocytes in 12-hour ATRA intervention group and 24-hour ATRA intervention group almost returned to normal.(2) In contrast with those in model group,the amounts of TGF-β1,Notchl,Jaggedl mRNA levels decreased in 12-hour ATRA intervention group (1.34 ±0.43 vs.4.16 ±0.31,1.67 ±0.2 vs.4.21 ±0.92,2.08 ±0.27 vs.5.14 ±0.63,q =23.83,11.45,19.67,all P ＜0.05) and 24-hour ATRA intervention group (1.22 ± 0.16 vs.4.16 ± 0.31,1.73 ± 0.53 vs.4.21 ± 0.92,2.08 ± 0.29 vs.5.14 ± 0.63,q =24.85,11.18,19.67,all P ＜ 0.05),and the differences were significant;similar trend was detected in the protein levels (1.04 ± 0.03 vs.4.31 ± 0.10,1.06 ± 0.04 vs.4.47 ± 0.24,1.07 ± 0.04 vs.4.20 ± 0.16,1.06 ±0.03 vs.4.31 ±0.10,1.07 ±0.03 vs.4.47 ±0.24,1.09 ±0.03 vs.4.20 ±0.16,q =163.50,69.61,90.36,162.50,69.40,89.78,all P ＜ 0.05),and the differences were significant;whereas the level of podocin mRNA (1.13 ±0.05 vs.0.40 ± 0.06,1.16 ± 0.03 vs.0.40 ± 0.06,q =36.50,38.00,all P ＜ 0.05) and protein (1.01 ± 0.01 vs.0.44 ±0.01,1.02 ±0.01 vs.0.44 ±0.01,q =180.25,183.41,all P ＜0.05) increased,and the differences were sig nificant.(3) The expressions of Notch1,Jagged1 mRNA were positively correlated with TGF-β1 mRNA (r =0.84,1.00,all P ＜ 0.05),but negatively correlated with podocin mRNA (r =-0.95,-0.94,all P ＜ 0.05) in model group.Conclusions ATRA might alleviate podocyte injury through cutting the expressions of TGF-β1,Notch1,Jagged1 and raising the expression of podocin in injured podocytes induced by ADR.

C-type natriuretic peptide(CNP),mainly expressed in central nervous system and vascular endothelial cells maintains renal homeostasis by autocrine or paracrine pathway,which regulates water-electrolyte metabolism,vascular resistance,glomerular permeability,and cell proliferation.Thus,clarifying the characteristics of CNP metabolism in kidney would appear promising to develop some new prospects for the evaluation of kidney injury and the targeted therapy.

Aim To investigate the effects of all-trans retinoic acid and benazepril on the expression of ?-smooth muscle actin in rats with glomerulosclerosis.Methods 80 Wistar male Rats were randomly assigned into the following groups: control group,model group,ATRA treatment group and benazepril treatment group,20 rats in each group.GS rats were uninephrectomized and injected with adriamycin(5mg?kg-1) after one week through the tail vein.All rats were sacrificed at the 12th week,GS was evaluated by glomerulosclerosis index(GSI) system.The expression of ?-SMA was assessed by reverse transcription-polymerase chain reaction(RT-PCR) and immunohistochemistry.Results Comparing with control group,the expression of ?-SMA mRNA and protein were decreased significantly in ATRA treatment group and benazepril treatment group(P0.05).Conclusions The postponed effects of ATRA and benazepril on GS were evident and equivalent.

Objective To investigate the effect and adverse reactions of intravenous cyclophosphamide (CTX) pulse therapy on refractory nephrotic syndrome (RNS) in children. Methods Retrospective study was carried on 102 patients with RNS treated with high dose CTX impact treatment in The First Hospital Affiliated to Guangxi Medical University from August 2006 to August 2016. Clinical data and follow-up records were analyzed. Results Biochemical indicators significantly improved after treatment ,and the difference was statistically signifi-cant(P < 0.05). Fifty-six patients achieved complete remission,and 21 patients achieved partial remission,with an effective percentage of 75.5%,and adverse drug reactions incidence rate of 19.6%. There was not significant difference in the remission rate of different clinical types. Conclusions High dose of CTX shock treatment on children refractory nephrotic syndrome is effective ,with low adverse reactions incidence.

Objective To explore the effect of overexpression of retinoic acid receptor α(RARα)on epithelial-to-mesenchymal transition(EMT)induced by hypoxia in renal tubular epithelial cells(NRK-52E).Methods The RARα lentivirus vector and negative control lentivirus vector were synthetised.The NRK-52E cells were divided into 4 groups:the normal control group,the hypoxia model group,the transfection group and the negative control group.Puro-mycin(2 mg/L)was added in transfection group and negative control group for screening after gene interference for 72 h.Then the 2 groups were subjected to hypoxia/reoxygenation,but the normal control group had no treatment. The change of cellular morphology was observed by using light microscope;the mRNA and protein expressions of RARα, E-cadherin,α -smooth muscle actin(α-SMA)in NRK-52E cells were detected by adopting reverse transcription-polymerase chain reaction(RT-PCR)and Western blot after hypoxia for 48 h.Results (1)Light microscope re-vealed that cells in both hypoxia model group and negative control group cells became atrophic and elongated,which were consistent with the morphology of myofibroblasts.But cells in transfection group cells were cubic,forming an epi-thelial monolayer.(2)Compared with the normal control group,the mRNA and protein expressions of RARα and E-cadherin in hypoxia model group were dramatically reduced(mRNA:0.58 ± 0.12 vs.1.00 ± 0.00,0.11 ± 0.00 vs. 1.00 ± 0.00,t= -0.63,767.30,all P<0.05;protein:0.63 ± 0.12 vs.1.62 ± 0.16,0.44 ± 0.22 vs.1.27 ± 0.08,t=8.61,6.19,all P<0.05),but the mRNA and protein expressions of α-SMA were higher(3.47 ± 0.83 vs.1.00 ± 0.00,1.39 ± 0.16 vs.0.64 ± 0.10,t= -5.01,-6.91,all P<0.05).(3)The mRNA and protein expressions of RARα and E-cadherin in the transfection group were significantly increased,compared with hypoxia model group(mRNA:4.69 ± 1.34 vs.0.58 ± 0.12,0.23 ± 0.00 vs.0.11 ± 0.00,q=9.13,25.48,all P<0.05;protein:1.39 ± 0.19 vs. 0.63 ± 0.12,0.87 ± 0.09 vs.0.44 ± 0.22,q=7.92,4.30,all P<0.05)and negative control group(mRNA:4.69 ± 1.34 vs.0.55 ± 0.21,0.23 ± 0.00 vs.0.12 ± 0.01,q=9.20,23.35,all P<0.05;protein:1.39 ± 0.19 vs.0.65 ±0.18,0.87 ± 0.09 vs.0.39 ± 0.21,q=7.71,4.80,all P<0.05).Conversely,the mRNA and protein levels of α-SMA were obviously lower in transfection group(1.52 ± 0.34 vs.3.47 ± 0.83,4.05 ± 0.81,0.82 ± 0.13 vs.1.39 ± 0.10,1.17 ± 0.10,q=4.88,6.33,7.50,4.61,all P<0.05).The difference in mRNA and protein expressions of RARα,E-cadherin,α-SMA between the hypoxia group and the negative control group had no statistical significance (all P>0.05).Conclusion Overexpression of RARα could alleviate EMT of renal tubular epithelial cells induced by hypoxia.

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.

Objective To explore the role of c-Jun N-terminal protein kinase(JNK)pathway in renal tubular epithelial cells(RTEC)transdifferentiation by detecting the expression of JNK pathway in the injury of hypoxic RTEC. Methods In vitro cultured rat RTEC were randomly divided into four groups of normal control, hypoxia,inhibitors,dimethyl sulfoxide(DMSO). The groups of hypoxia,inhibitor and DMSO were placed into a vacuum tank to establish hypoxia model. The cells were harvested 6,12 and 24 h after hypoxia started. RT-PCR and Western blot test were used to detect the mRNA expressions of alpha smooth muscle actin(α- SMA)and protein expressions of JNK,pJNK and alpha SMA,respectively,in all the groups. Results Hypoxia induced significantly increased expressions of α-SMA mRNA and proteins,and JNK and pJNK proteins as well in RTEC (all P<0.05).After addition of inhibitors,the expression of α-SMA mRNA and proteins,the protein expression of pJNK in RTEC were significantly decreased(all P < 0.05)and the expression of JNK protein was significantly increased(P < 0.05). There was no significant difference in the expressions of JNK,pJNK,α-SMA in RTECs between hypoxia group and DMSO group(all P>0.05).There was a significant positive correlation between pJNK protein and α-SMA protein expression(P < 0.01). Conclusion In hypoxic RETC injury in rats,JNK pathway may be involved in the RTEC phenotype transdifferentiation.