Effects of pentoxifylline on hepatic nuclear factor-kappa B signaling pathway and insulin resistance in nonalcoholic steatohepatitis rats induced by fat-rich diet / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To explore the effects of pentoxifylline (PTX) on nuclear factor-kappa B (NF-kB) signaling pathway, insulin receptor substrates (IRSs) and glucose transporter 2 (GLUT2) expressions in livers in a rat model of nonalcoholic steatohepatitis (NASH).</p><p><b>METHODS</b>Rats fed a fat-rich diet for 4 weeks were randomly allocated into two groups; the model group rats (n = 12) were fed a high-fat diet alone and the PTX group rats (n = 12) were fed a high-fat diet plus PTX (100 mg x kg(-1)/d(-1)) in drinking water. Meanwhile, rats (n = 6) fed a standard diet from the start served as controls. All the rats were sacrificed at the end of the 24th week. Hepatic NF-kappaB binding activity was measured by electrophoretic mobility shift assay (EMSA). The expression of tumor necrosis factor (TNF) alpha and inhibitor kappaB (IkappaBalpha) proteins in livers were determined by Western blot. Messenger RNA of IRS-1, IRS-2 and GLUT2 expressions were examined by RT-PCR.</p><p><b>RESULTS</b>NF-kappaB binding activity was higher in the model group than that in the controls, while it was lower in the PTX group compared with that in the model group. The expression of TNFalpha protein was markedly increased in the model group (vs. the control group) but decreased in the PTX group (vs. the model group). The expression of IkappaBaalpha protein was decreased in the model group (vs. the control group) but increased in the PTX group (vs. the model group) to a certain extent. IRS-2 mRNA expression was markedly increased in the model group, and significantly decreased in the PTX group when compared with the model group (P less than 0.01).</p><p><b>CONCLUSIONS</b>PTX could influence NF-kappaB signaling pathway and IRS expression in livers of NASH rats, which might be involved in the improvement of hepatic insulin resistance.</p>

A study of the changes of hepatic gene expression in the process of nonalcoholic fatty liver disease development using U230A oligonucleotide microarray / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To explore the changes of hepatic gene expression during the course of nonalcoholic fatty liver disease (NAFLD) development in rats.</p><p><b>METHODS</b>A rat model of NAFLD was developed by feeding the animals a high-fat diet for 24 weeks. Liver tissues of the model rats and the control rats were analyzed at different time points using rat U230A (Affymetrix GeneChip), which covers 15650 genes.</p><p><b>RESULTS</b>Compared with the control rats, the number of genes expressed differently in the model group rats at 4 and 8 weeks was 426 and 540. The up-regulated genes among them were intracellular phosphorylase genes, metabolic enzyme genes, fatty acid binding protein genes, cytochrome P450 genes, cellular transcription and differentiation genes. The down-regulated genes were ionic channel genes, hormone receptor genes, and cytoskeleton genes. At the 12th week, the number of the genes expressed differently was 501, in which 352 were up-regulated genes, including genes related to inflammation and apoptosis such as interleukin and Toll-like receptor 4. At the 16th week, the number of the differently expressed genes was 665, with 430 up-regulated, such as those related to the inflammation and apoptosis genes and collagen I and fibrosis genes, however cell regeneration genes were down-regulated. At the 24th week the number was 663, of which fibroblast growth factor, transforming growth factor and insulin-like growth factor genes were up-regulated. Of all the differently expressed genes, the number of up-regulated genes was 128, including 10 lipogenic genes, 46 metabolic genes, 15 inflammation genes, 10 apoptosis genes, and 16 fibrosis genes; and the down-regulated genes were 52, including 6 hormone receptor genes, 5 cell regeneration genes and 11 electron transport genes.</p><p><b>CONCLUSION</b>The changes of the hepatic gene expression of rats fed a fat-rich diet are related to the duration of the feeding, and are correlated with their histopathology in the livers.</p>