Brassica rapa L., also called NIUMA, is used empirically in Tibetan medicine for its antioxidant, anti-inflammatory and antiradiation activities. This study explored the hepatoprotective effects of B. rapa polysaccharides (BRPs) on acute liver injury induced by carbon tetrachloride (CCl4 ) in mice and the underlying mechanisms. Mice were treated with CCl4 after the oral administration of BRPs (55, 110 and 220 mg/kg) or bifendate (100 mg/kg) for 7 days. Blood and liver samples of mice were collected for analysis after 24 h. The ALP, ALT and AST levels and the biological activities of SOD, MDA and GSH-Px were measured. Histopathological changes in the liver were determined through hematoxylin and eosin staining. Moreover, TNF-α, IL-1β and IL-6 expression levels were detected by commercial reagent kits. Finally, Western blot analysis was used to check the relative expression levels of caspase-3, p-JAK2 and p-STAT3. The BRP pre-treatment significantly decreased the enzymatic activities of ALT, ALP and AST in the serum, markedly increased the activities of SOD and GSH-Px in the liver and reduced the MDA concentration in the liver. BRPs alleviated hepatocyte injury and markedly inhibited the expression of TNF-α, IL-1β and IL-6, also downregulating the CCl4 -induced hepatic tissue expression of caspase-3. Furthermore, BRPs inhibited the JAK2/STAT3 signaling pathway in a dose-dependent manner in the liver. This study demonstrated that BRPs exert hepatoprotective effect against the CCl4 -induced liver injury via modulating the apoptotic and inflammatory responses and downregulating the JAK2/STAT3 signaling pathway. Therefore, B. rapa could be considered a hepatoprotective medicine.
Keywords: Brassica rapa; apoptotic; biological activity; hepatoprotective effects; inflammatory; polysaccharides.
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