Effects of pyrrolidine dithiocarbamate on the expression of nuclear factor-κB and its inhibitor in rat liver fibrosis

Objective To evaluate the inhibitory effect of pyrrolidine dithiocarbamate (PDTC) on the expression of nuclear factor-κκB (NF-κB) and Ikappa B in rat liver fibrosis.Methods Thirty-eight male Sprague-Dawley rats were randomly divided into three groups:group A,group B and group C separately.The rats in groups B and C were randomly classified into 2-week and 4-week subgroups,which were injected intraperitoneally with dimethyl-nitrosame for weeks to establish the rat liver fibrosis model.The rats in group C were subcutaneously injected with dimethyl-nitrosame and given oral administration of PDTC.The liver tissues underwent hematoxylin-eosin staining and masson staining.The activity of NF-κB p65 was detected by the chemiluminescence eleetrophoretic mobility shift assay (EMSA).The expression of NF-κB p65 mRNA was detected by real-time polymerase chain reaction (Real-time PCR).The expression levels of NF-κB p65 and IkappaB alpha (IκBα) were observed by immunohistochemical staining technique.Results NF-κB p65 activity in group A,B2week subgroup,B4werk subgroup,C2week subgroup and C4week subgroup was (28.5 ±3.3)％,(66.8 ±6.7)％,(76.6 ±6.0)％,(39.8 ±5.1)％ and (51.2 ±4.6)％ respectively.NF-κB p65 mRNA expression in group A,B2 week subgroup,B4 week subgroup,C2week subgroup and C4 week subgroup was 0.003 0 ±0.001 4,0.009 0±0.002 2,0.019 3 ±0.005 0,0.003 9±0.001 3,and 0.009 5 ± 0.002 1 respectively.The number of NF-κB p65 positive cells in in group A,B2 week subgroup,B4week subgroup,C2week subgroup and C4week subgroup was 14.68 ±2.98,48.33 ±2.31,68.60 ±4.65,34.27 ± 1.77,and 49.65 ± 3.60 respectively.The number of IκBα positive cells in group A,B2week subgroup,B4week subgroup,C2 week subgroup and C4week subgroup was 10.81 ±0.43,22.82 ± 1.42,31.63 ±2.51,17.92 ±0.48,and 24.96 ± 1.17 respectively.Masson collagen staining area in group A,B2week subgroup,B4 week subgroup,C2week subgroup and C4week subgroup was (4.47 ±2.01) μm2,(13.20 ±2.38) μm2,(36.30 ±8.10) μm2,(9.08 ±0.80) μm2,and (19.77 ±2.04) μm2 respectively.Activity and mRNA expression of NF-κB p65,the number of immunohistochemical staining positive cells and Masson collagen staining area of NF-κB p65 and IκBα were reduced in group A,and began to increase at week 2 and were significantly increased at week 4 in groups B and C (P ＜0.01 or P ＜0.05,respectively).And those items in group C were significantly lower than those in group B (P ＜0.01 or P ＜0.05,respectively).The activity of NF-κB p65 was positively related with the expression of NF-κB p65 mRNA,the immunohistochemical staining of NF-κB p65 and IκBα,and the area of Masson collagen staining in hepatic tissue (r =0.747,0.780,0.779,and 0.780,respectively,P ＜ 0.01).Conclusion NF-κB/IκBα takes important part in the course of rat liver fibrosis,and can promote the liver inflammation and fibrosis in rats.PDTC might prevent the hepatic fibrosis by suppressing the activation of NF-κB. Key words: Pyrrolidine dithiocarbamate ;  Liver fibrosis ;  Nuclear factor-κB ;  IkappaB