Abstract

Objective: Medicinal plant studies have documented diverse pharmacological applications and biological activities of different parts of such plants but still with insufficient knowledge about molecular mechanisms of applications and activities. This study was therefore carried out to assess the expression of molecular markers of cell cycle and proliferation (Ki-67 and p53 proteins) in hepatic tissue of rats exposed to aqueous leaf extracts of A. conyzoides L. and possible effects of exposure on hepatic tissue proliferative ability. Methods: This study involved 20 male Wistar rats (170-180g) divided into four groups (A-D), groups A was non-treated control while groups B-D were administered aqueous extracts of A. conyzoides L. at dose rate of 100, 300 and 500 mg/kg b.wt. orally for 28 days. After the treatment period, animals were sacrificed, liver tissues were harvested and processed, tissue sections produced were stained with histological staining (H & E) techniques and immunohistochemically stained for cell prolif eration (Ki-67) and tumor suppressor (p53) protein with HRP-DAB staining technique (using monoclonal antibody). Stained sections were analyzed using image-J software. Data obtained were statistically analyzed using IBM-SPSS (version 20) and compared using T-test and analysis of variance (ANOVA). Results: The result of this study showed significant decrease (p<0.05) in the Ki-67 protein expression level but no significant difference in the p53 protein expression level in hepatic tissues of all treatment groups relative to the non-treated group. Conclusion: The aqueous extracts of A. conyzoides L. exhibit significant down-regulatory effect on the expression of cell proliferation (Ki-67) protein in hepatic tissues of study animals and this may indicate prominent anti-proliferative activity of the extracts.