title: [Role of protein phosphatase 2A in renal interstitial fibrosis].
abstract: BACKGROUND
  To explore the role of protein phosphatase 2A (PP2A) in renal interstitial fibrosis by using rat model of unilateral ureteral obstructive (UUO) or cell model of human kidney proximal tubular epithelial (HK)-2 cells treated with transforming growth factor-β1 (TGF-β1).
  
  
  METHODS
  1) A total of 15 Sprague-Dawley rats were randomly divided into a sham group, a UUO group and an okadaic acid (OA) treated group (OA group) (n=5 in each group). The OA  [30 μg/(kg·d)], diluted with 1.8% alcohol, was given to the rats in the OA group through gastric tube after at 72 h after the surgery, while the equal volume of 1.8% alcohol was given to the rats in the sham group and the UUO group. After sacrificing rats, the blood and kidney were collected to detect the renal function and the expression of PP2Ac, fibronectin (FN), collagen-I (Col-I), E-cadherin (E-cad) and α-smooth muscle actin (α-SMA) by immunohistochemistry, Western blot and RT-PCR, respectively; 2) The likely concentration of OA was determined by Trypan blue dye exclusive assay and methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The HK-2 cells were incubated with serum-free Dulbecco's modified eagle medium (DMEM) for 24 h; then they were divided into a control group, a TGF-β1 group (treated with 5 ng/mL TGF-β1 for 24 h) and a TGF-β1+OA group (treated with 5 ng/mL TGF-β1 and 40 nmol/L OA for 24 h). The HK-2 cells were collected and the expression of PP2Ac, FN, Col-I, E-cad and α-SMA were detected by Western blot.
  
  
  RESULTS
  1) Compared with the sham group, the BUN and Scr in the UUO group increased (both P<0.05); compared with the UUO group, the BUN and Scr in the OA group decreased (both P<0.05); the expression of PP2Ac, FN, Col-I and α-SMA was up-regulated while the expression of E-cad was down-regulated in the UUO group compared with those in the sham group (all P<0.05). The expression of PP2Ac, FN, Col-I and α-SMA was down-regulated while the expressions of E-cad was up-regulated in the OA group compared with those in the UUO group (all P<0.05); 2) The likely concentration of OA was 40 nmol/L. Western blot showed that the expression of PP2Ac, FN, Col-I and α-SMA was up-regulated while the expressions of E-cad was down-regulated in the TGF-β1 group compared with those in the control group (all P<0.05); the expression of PP2Ac, FN, Col-I and α-SMA were down-regulated while the expression of E-cad was up-regulated in the TGF-β1+OA group compared with those in the TGF-β1 group (all P<0.05).
  
  
  CONCLUSIONS
  PP2A might be able to promote the renal interstitial fibrosis. .
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011; Department of Nephrology, Changsha Central Hospital, Changsha 410004, China.
authors.forename: Yiyun
authors.initials: Y
authors.lastname: Xi
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: You
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Shaobin
authors.initials: S
authors.lastname: Duan
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Youming
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Nephrology, Second Xiangya Hospital; Institute of Nephrology, Central South University, Changsha 410011, China.
authors.forename: Fuyou
authors.initials: F
authors.lastname: Liu
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002460:Cell Line; D024042:Collagen Type I / Q000378:metabolism; D004365:Drugs, Chinese Herbal; D005353:Fibronectins / Q000378:metabolism; D005355:Fibrosis; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D007674:Kidney Diseases / Q000201:enzymology*; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology
chemical_list: D000199:Actins; D015820:Cadherins; D024042:Collagen Type I; D004365:Drugs, Chinese Herbal; D005353:Fibronectins; D054648:Protein Phosphatase 2; D053773:Transforming Growth Factor beta1; C498862:Acta2 protein, rat