Effects of Aqueous Extract of Plumbago zeylanica L. in the Reversal of DMN-induced Hepatic Fibrosis in Rat

摘要

[Objectives] This study was conducted to evaluate the action of the aqueous extract of a medicinal plant Plumbago zeylanica L. in the reversal of dimethylnitrosamine( DMN)-induced hepatic fibrosis in rats,and to provide a scientific basis for the utilization of P. zeylanica in treatment of hepatic fibrosis. [Methods] Hepatic fibrosis in rats was induced by intraperitoneal injection of DMN. The rats were then given the aqueous extract of P. zeylanica at high,medium or low concentration by gavage for five weeks. Serum level of alanine aminotransferase( ALT) was determined by lactate dehydrogenase( LDH)-release assay,and serum level of aspartate transaminase( AST) was measured by UV-malate dehydrogenase( MDH) assay. Serum levels of total bilirubin( TBIL),direct bilirubin( DBIL)and indirect bilirubin( IBIL) were measured by vanadate oxidation assay. Four indices of hepatic fibrosis( hyaluronic acid,laminin,procollagen type Ⅲ and collagen type IV) were determined by radioimmunoassay( RIA) assay. Morphological damage of liver tissue was observed by hematoxylin-eosin staining( H&E staining). Immunohistochemical staining was performed to determine the location and area of deposited collagen type I,collagen type Ⅲ and α-smooth muscle actin( α-SMA) in liver tissue. [Results]Compared with the negative control( rats with diseased liver and untreated with P. zeylanica aqueous extract),the serum levels of ALT,AST,TBIL,DBIL and IBIL were significantly decreased by P. zeylanica aqueous extract; the levels of the four serum indices of hepatic fibrosis were also obviously reduced. H&E staining showed that hepatic fibrosis in rats was obviously inhibited or even reversed by P. zeylanica aqueous extract. Immunohistochemical staining proved that the aqueous extract of P. zeylanica significantly reduced the area and coloration of collagen type I,collagen type Ⅲ and α-SMA in rat liver. [Conclusions] The aqueous extract of P. zeylanica has a definite effect in reversal of DMN-induced hepatic fibrosis in rat by promoting the recovery of liver function,reversal of histopathological changes and reducing fibrotic collagen.