Abstract
AIM: To establish a rapid rat model of non-alcoholic fatty liver.
METHODS: Twenty-four male Sprague Dawley rats were averagely and randomly divide into group A, B and C, fed with normal diet, routine high-fat diet and routine high-fat diet plus sucrose, propylthiouracil, and sodium cholate, respectively. The general conditions and weight changes were dynamically observed for 5 wk, and then all the rats were killed. The pathological changes of liver tissues were observed by HE staining, and Sudan IV staining and electron microscopy were used to investigate the presence status of cytoplasmic lipid droplets in liver cells. The following indexes were compared between the three groups, including serum levels of triglyceride (TG), total cholesterol (TC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), and superoxide dismutase (SOD), and tissue contents of TG and TC.
RESULTS: Starting from the fourth week, the weights of rats were significantly decreased in group A and C as compared with those in group B (249.63 ± 34.25, 241.88 ± 20.75 vs 275.38 ± 6.59, P < 0.05), but there was no marked difference between group A and C (P > 0.05). In the 5th week, light microscopy showed a great number of fatty vacuoles in liver cells, and electron microscopy confirmed the presence of abundant lipid droplets. Different degrees of hepatic fatty degeneration (+~+++) was observed in group C (H = 13.36, P = 0.0003), but not in group A and B. The serum levels of TG, TC, ALT and MDA were markedly higher in group C than those in group A and B (TG: 1.28 ± 0.61 mmol/L vs 0.72 ± 0.12, 0.76 ± 0.04 mmol/L; TC: 12.78 ± 1.47 mmol/L vs 1.71 ± 0.03, 2.31 ± 0.49 mmol/L; ALT: 1518.64 ± 186.04 nkat/L vs 1181.57 ± 37.84, 1262.92 ± 159.20 nkat/L; MDA: 13.40 ± 4.24 μmol/L vs 5.89 ± 1.05, 7.23 ± 1.15 μmol/L; all P < 0.05), but the activity of SOD was lower in group C (5.21 ± 0.81 nkat/mL vs 11.91 ± 2.69, 11.19 ± 0.78 nkat/mL, P < 0.05). There were no notable differences between group A and B (P > 0.05). The tissue contents of TG and TC were dramatically higher both in group B and C than those in group A (TG: 2.14 ± 0.26, 5.83 ± 1.42 mmol/L vs 1.20 ± 0.16 mmol/L, P < 0.05; TC: 3.19 ± 0.23, 9.63 ± 1.12 mmol/L vs 2.13 ± 0.16 mmol/L, P < 0.05), and there was also statistical difference between group B and C (P < 0.05).
CONCLUSION: The rat model of non-alcoholic fatty liver can be successfully established within 5 wk by the improved method, which needs less time and cost during the construction, and basically simulating the occurrence and progression of non-alcoholic fatty liver in human beings.
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