Objective: To observe the expression of nuclear factor-κB (NF-κB)and plasminogen activator inhibitor-1(PAI-1) of the renal interstitial in rat unilateral ureteral obstruction (UUO) model and the renoprotective effect of bicyclol

and then to explore the mechanisms. Method: Renal interstitial fibrosis rat model was produced by unilateral ureteral obstruction

eighty-one rats were randomly assigned to shame operation group

UUO model group and bicyclol-treated group. After operations rats in bicyclol-treated group were intregastric administration(ia) at bicyclol 200 mg ·kg-1 once a day until rats were killed. Rats in sham-operated group and UUO model group were intragastric administrated at identical voluminal normal saline. In each group

nine rats were chosen randomly to be killed at the 7

14 and 21 d after operation for histological examination of kidney tissue.Renal tissues were examined by HE and Masson stain. The expression of NF-κB and PAI-1 were detected by immunohistochemical staining

and the expression of PAI-1-mRNA in renal tissue was determined by reverse transcription-polymerase chain reaction (RT-PCR). Result: The relative area of renal interstitial fibrosis of UUO model group at 7

14 and 21 d was (13.03±0.66)%

(25.76±1.47)%

and (53.16±2.45)%respectively. And that of bicyclol-treated group was (9.63±0.58)%

(16.84±0.83)% and(33.59±1.61)% respectively. Compared with UUO model group

fibrotic area of bicyclol-treated group was decreased markedly(P<0.05

respectively). The protein expression of NF-κB of UUO model group at 7

14 and 21 d was (11.73±0.42)%

(22.56±0.69)% and(36.27±1.14)% respectively

but that of bicyclol-treated group was (5.67±0.42)%

(10.79±0.37)% and(26.62±0.23)% respectively. The protein expression of PAI-1 of UUO model group at 7

14 and 21 d was (7.29±0.23)%

(12.32±0.20)% and (18.36±0.19)% respectively

but that of bicyclol-treated group was (4.26±0.14)%

(7.69±0.13)% and (13.35±0.21)% respectively. The expression of PAI-1 mRNA of UUO model group at 7

14 and 21 d was (1.17±0.10)

(2.29±0.07) and (3.33±0.10) respectively

but that of bicyclol-treated group was (0.32±0.03)

(1.18±0.05)and(2.06±0.40) respectively. Compared with UUO model group

the expression of NF-κB

PAI-1 protein and PAI-1 mRNA of bicyclol-treated group was decreased markedly(P<0.05

respectively). Conclusion: Bicyclol can alleviate the degree of renal interstitial fibrosis and protect renal function

down-regulates the expression of PAI-1 and NF-κB

thus blocking the renal fibrosis.