Inhibitory effect of TCCE on CCl4-induced overexpression of IL-6 in acute liver injury.

Terminalia catappa L. leaves have been shown to protect against acute liver injury produced by some hepatotoxicants, but the active components and mechanisms are not clear. This study was designed to characterize the protective effects of the chloroform fraction of the ethanol extract of T. catappa leaves (TCCE) against carbon tetrachloride (CCl4)-induced hepatotoxicity in mice, and analyze the changes in expression level of interleukin-6 (IL-6) in the process. It was found that TCCE pretreatment (10 or 30 mg/kg, ig) protected mice from CCl4 toxicity, as evidenced by the reversed alterations in serum alanine aminotransferase (sALT) and serum aspartate aminotransferase (sAST) activities. Additionally liver tissues were subjected to RT-PCR, Western blot and immunohistochemistry to analyze changes in IL-6 expression. It was found that TCCE markedly suppressed the CCl4-induced over-transcription of IL-6 gene. Consistent with the result, the expression of IL-6 protein was also blocked by TCCE in CCl4-stimulated mice, especially in the area around central vein on liver tissue section. In conclusion, TCCE is effective in protecting mice from the hepatotoxicity produced by CCl4, and the mechanisms underlying its protective effects may be related to the inhibition on the overexpression of IL-6 mainly around terminal hepatic vein.