| Objective To study the Effects of hyperbaric oxygen(HBO) combined with free-radical antagonists on the expression and activity of matrix metalloproteinase-2(MMP-2) and mediated factors of MMP-2 in rat liver Methods Liver fibrosis model was induced by subcutaneous injections of carbon tetrachloride (CCl4) in rats(twice weekly for 8 weeks). Sixty male Wistar rats were randomly divided into five groups including the normal control group(C), model group(M), hyperbaric oxygen group(H), anti-free radical agencies group(Fr), hyperbaric oxygen combined with free-radical antagonists group(HFr), the rats in specific groups were discontinuously treated with HBO , free-radical antagonists and in combination respectively at the 2nd and 8th week during the experiment. Then the rats were killed at the 2nd and 8th weekends. The hepatic pathological changes were observed; serum malondialdehyde (MDA),MMP-2 activity was detected separately by spectrophotometer and zymography; the expression of MMP-2 and transforming growth factor (TGF-β1),metallothionein(MT)of hepatic tissues were examined by immunohistochemistry stains and analyzed by a semi-quantitative method; reverse transcription-polymerase chain reaction(RT-PCR)was used to evaluate MMP-2 mRNA expression.Results The results of histopathology showed that liver fibrosis was induced successfully in rats. At the 2nd weekend, the weight ratio of liver and body(WR), the index of hepatic lesion in HFr group were lower than those in the model group(P<0.01), the expression of MMP-2 protein and its mRNA level , serum gelatinase activity and TGF-β1 expression in this group were also lower than those in the model group(MMP-2 positive index: M,56.75±3.03; HFr,5.40±1.34; P<0.01。MMP-2 mRNA:M,0.547±0.013;HFr,0.155±0.005;P<0.01. MMP-2 activity:M,10.47±2.23;HFr,1.07±0.73;P<0.05; TGF-β1 positive index:M,4.96±0.28;HFr,3.28±0.33;P<0.01). Compared with HBO group ,the expression of MT protein and serum MDA in HFr group decreased significantly (MT positive index:H,42.44±5.93;HFr,16.57±2.20; P<0.01.MDA:H,11.798±5.439;HFr,6.303±2.430;P<0.05). At the 8th weekend, the WR, the index of liver fibrosis in HFr were significantly lower than those in model and remarkably lower than others. The expression of MMP-2 protein and its mRNA level were also lower than those in the models, while MMP-2 activity was higher than the model (MMP-2 positive index: M,119.57±8.08;HFr,12.53±2.51;P<0.01.MMP-2 mRNA:M,0.685±0.014;HFr,0.506±0.013;P<0.01. MMP-2 activity:M,4.29±1.13;HFr,9.60±2.32;P<0.05.) The changes of TGF-β1,MT and MDA were similar to those at 2nd weekends.(TGF-β1 positive index:M,7.76±0.39;HFr,4.97±0.35;P<0.01. MT positive index:H,49.92±6.04;HFr,6.50±2.29; P<0.01。MDA:M,14.346±2.579;HFr,6.863±2.822;P<0.05).At the 2nd and 8th weekends in HBO group, the liver lesion was lighter than that of model, but not significantly; MDA level and MT positive index were highest among all groups and higher than those in model, MMP-2 activity was higher than that of control. It showed that the items including the liver lesion, MMP-2 protein and activity , TGF-β1 in Fr group at the 2nd weekends were all lower than those in model, moreover, MDA and MT were the lowest in all groups. It was also found both of Fr group and HBO group had almost identical to extent of fibrosis at the 8th weekend, and MMP-2 activity in Fr group was higher than that obtained of model.Conclusions 1 Hyperbaric oxygen combined with free-radical antagonists can lighten hepatic lesions caused by CCl4 and retard the development of liver fibrosis;2 The fact that the expression of MMP-2 in rat hepatic tissues in HFr group was not intense at both time points,the activity was low at the 2nd weekend but high at the 8th weekend,reveals that hyperbaric oxygen combined with free-radical antagonists are mainly to inhibit the expression of this enzyme, which differs in extent at the different stages of the liver fibrogenesis. Therefore, this treatment is useful for reducing collagen Ⅳ decomposition arou...
|
PDF Full Text Request