| ObjectiveTo establish two fatty liver models of rats: high-fatty diet induced nonalcoholic fatty liver (NAFL), high-fatty diet and alcohol induced compound fatty liver(CFL), to investigate their possible mechanism, and to study the effect of hepatic stimulator substance(HSS) on the two fatty liver models and their possible mechanism after the models were made.Methods1. Establishment of fatty liver model of rats: rats were divided into two experiment groups. The rats of high-fatty diet group were just fed with 20℅ corn oil (high fatty group), while the rats of compound diet group were fed with 20℅ corn oil and intragastrically infused with high degree white spirits at the same time (high fatty and alcohol group). Rats of the control group were just fed normal diet (control group). All rats were killed and the serum and liver were obtained after six weeks. The weight, liver index, the serum TG, TC, AST, ALT and the hepatic TG, MDA, Hyp, and SOD were detected. The liver pathological changes were observed with light and electron microscope, and the expression of TGFβ1 and PDGF-B in liver was detected with immunohistochemistry.2. HSS was purified from porkling livers. The purification steps included homogenate, ultrasonication, heat denaturation, alcohol precipitation, et al. The growth effects of HSS on SMMC-7721 cells were measured by [3H]-TdR incorporation method.3. Two fatty liver models of rats were treated with the low and high doses HSS purified from porkling livers (HSS group), non intervention treatment was used as control group (non treatment control group), and the simvastatin as drug control group (drug control group). The rats were killed after two weeks treatment, the serum TG, TC, AST, ALT, and hepatic TG, MDA, Hyp, SOD, and the expression of TGFβ1 and PDGF-B in liver were detected, and the effects of HSS were observed.Results1. The rats of high fatty diet group whose serum TG(1.07±0.20 vs 0.81±0.23), AST(211.67±44.57 vs 147.44±31.76) and ALT(73.78±11.69 vs 53.67±15.40); and hepatic TG(5.81±2.53 vs 1.65±0.58) and MDA(19.17±5.10 vs 14.88±2.43), and the positive rate of expression of TGFβ1(63.64% vs 9.09%) and PDGF-B(36.36% vs 0%), and rate of fatty liver (100% vs 0%) were significantly higher than the control group, respectively( all P<0.05). The rate of steatohepatitis of the rats of high fatty alcohol group was increased remarkably compared with the control group (44.44% vs 18.18%, P<0.05).2. The purified HSS from porkling livers might promote to incorporate [3H]-TdR into the liver cell obviously.3. The two NAFL and CFL models of rats treated with simvastatin, the serum TG (0.66±0.14 vs 0.89±0.15 / 0.69±0.21 vs 1.19±0.32), hepatic TG (2.39±0.90 vs 6.34±2.76 / 1.74±0.84 vs 4.95±3.20) and the fatty liver rates (100% vs 50% / 100% vs 42%) were decreased remarkably compared with the control group, respectively(all P<0.05).4. The serum AST(153.75±37.14 vs 212.63±38.03) and ALT(54.75±10.90 vs 82.75±33.47), and hepatic TG(3.60±2.10 vs 6.34±2.76), MDA(14.72±2.51 vs 19.81±5.38), Hyp (0.13±0.05 vs 0.19±0.05), and TGFβ1(25.0% vs 87.5%) were significantly decreased(all P<0.05), hepatic SOD(56.42±3.10 vs 47.85±5.32, P<0.01) was remarkably increased in NAFL rats treated with high dose HSS compared with the non treatment control group. The hepatic SOD was remarkably increased in NAFL rats treated with high dose HSS compared with the non treatment control group or low dose HSS group(56.42±3.10 vs 48.38±3.21 / 56.42±3.10 vs 48.74±2.22, P<0.01). The hepatic TG was remarkably decreased in NAFL rats treated with low dose HSS compared with the non treatment control group (3.53±1.79 vs 6.34±2.76, P<0.05). The two groups of CFL treated with low and high doses HSS were put together, the positive rate of PDGF-B was significantly lower than the non treatment control group (18.75% vs 62.5%, P=0.047).5. The serum TG(0.69±0.27 vs 1.19±0.32), AST(167.38±48.60 vs 222.75±53.79), ALT(59.38±17.64 vs 102.34±21.11), hepatic MDA(17.15±3.52 vs 25.95±7.25) and Hyp(0.15±0.06 vs 0.22±0.03) were significantly decreased(all P<0.05), hepatic SOD(54.50±2.77 vs 45.96±4.12, P<0.01) was remarkably increased, in CFL rats treated with high dose HSS compared with the non treatment control group. The hepatic SOD was remarkably increased in CFL rats treated with high dose HSS compared with the non treatment control group or low dose HSS group(54.50±2.77 vs 50.08±4.00 / 54.50±2.77 vs 51.56±2.34, P<0.05). The serum TG (0.71±0.25 vs 1.19±0.32) and ALT (75.38±20.19 vs 102.34±21.11), and hepatic MDA (17.17±3.95 vs 25.95±7.25) and Hyp (0.16±0.42 vs 0.22±0.03) were remarkably decreased (all P<0.05), hepatic SOD (51.56±2.34 vs 45.96±4.12, P<0.05) was remarkably increased in CFL rats treated with low dose HSS compared with non treatment control group. The two groups of CFL treated with low and high doses HSS were put together, the rate of steatohepatitis was significantly lower than the non treatment control group (25% vs 75%, P=0.028).Conclusions1. The elevation of serum TG, AST and ALT level of models, and the TG and MDA content of liver tissue were heightened in the rats of High-fatty diet group which were just fed with 20℅ corn oil, and the expression of TGFβ1 and PDGF-B in the liver tissue was increased .The nonalcoholic fatty liver animal model of rats was established, and could be used. Besides, the elevation serum TC level of models and the Hyp content of liver tissue were heightened in the rats of compound diet group which were fed with high fatty diet and alcohol, and this group could make more damage with liver function than that group which was just fed with 20℅ corn oil.2. The purified HSS from porkling livers by our methods could promote the liver cell growth efficiently.3. The less of serum AST and ALT level of models, and the MDA and Hyp content of liver tissue and the elevation of SOD activities were restored remarkably by HSS, the fatty degeneration and necrosis of hepatocytes in the liver were ameliorated, and the expression of TGFβ1 and PDGF-B in liver tissue were reduced in HSS group. The protective effect of HSS on liver damage may be due to its function to promote the growth of hepatocytes, strengthen the ability of anti-oxidative stress, and restrain collogen synthesis. |
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