ObjectiveTo investigate the protective effect of Lycium barbarum polysaccharide (LBP) combined with aerobic exercise (AE) on the liver of rats with nonalcoholic steatohepatitis (NASH) induced by high-fat diet based on the p38 mitogen-activated protein kinase (p38 MAPK)-nuclear factor-κB (NF-κB) pathway. MethodsAfter 1 week of adaptive feeding, 45 Sprague-Dawley rats, aged 8 weeks, were randomly divided into control group (10 rats fed with normal diet) and high-fat group (35 rats fed with high-fat diet). At the end of week 28, the high-fat group was randomly divided into model group, LBP group, AE group, and LBP+AE group, with 8 rats in each group, and intervention was performed for 10 weeks. At the end of the experiment, fasting blood glucose was measure for all rats, and serum samples, liver tissue, and visceral fat were collected. Biochemical kits were used to measure the serum levels of triglyceride (TG), total cholesterol (TC), alanine aminotransferase (ALT), and aspartate aminotransferase (AST); ELISA kits were used to measure the serum levels of fasting insulin (FINS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and monocyte chemotactic protein-1 (MCP-1); quantitative real-time PCR and Western blot were used to measure the mRNA and protein expression levels of Toll-like receptor 4 (TLR4), p38 MAPK, and NF-κB in liver tissue. A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t-test was used for further comparison between two groups. ResultsCompared with the control group, the model group had significant increases in TG, TC, AST, ALT, FINS, and homeostasis model assessment of insulin resistance (HOMA-IR) (all P ＜0.05), a tendency of increases in the serum levels of the inflammatory factors MCP-1, TNF-α, and IL-6 (all P ＜0.05), and significant increases in the mRNA and protein expression levels of TLR4, p38 MAPK, and NF-κB in liver tissue (all P ＜0.05). Compared with the model group, each intervention group had significant reductions in TG, TC, AST, ALT, FINS, and HOMA-IR (all P ＜0.05), a tendency of reductions in the serum levels of the inflammatory factors MCP-1, TNF-α, and IL-6 (all P ＜0.05), and significant reductions in the mRNA and protein expression levels of TLR4, p38 MAPK, and NF-κB (all P ＜0.05). Compared with LBP group, the LBP+AE group had significant reductions in TG, ALT, FINS, HOMA-IR, MCP-1, the mRNA expression level of TLR4, protein expression levels of p38 MAPK and NF-κB(all P＜0.05). Compared with Ae group, the LBP+AE group had significant reductions in FINS, HOMA-IR, IL-6, MCP-1, the mRNA expression level of TLR4 (all P＜0.05). ConclusionLBP combined with AE may improve inflammation in NASH rats by regulating the p38 MAPK/NF-κB pathway.