ABSTRACT
Objective To compare the effects of different extracts of Rheum palmatum on weight and tissue structure of hypothalamusand and pituitary of adult female rats,and screen the main reproductive toxicity extract.Methods The water,chloroform,ethyl acetate,and n-butanol extracts and water-soluble substance of R.palmatum were prepared by polarity gradient extraction method.Female adult rats were randomly divided into blank control group,rhubarb water extract group,and different extracts groups.The dosage of all the groups was equivalent to 4.00 g/kg crude rhubarb.Rats were administered with extracts by gavage for 60 d.Body mass growth rate of rats were calculated before and after administration.The pathological changes of hypothalamic arcuate nucleus neurons and pituitary gonadal cell were observed with light microscope.Results Compared with the blank control group,the body mass growth rate of rhubarb water extract group was decreased (P ＜ 0.05),while those in the different extracts groups were increased (P ＜ 0.01);The hypothalamic arcuate nucleus neurons of rhubarb water extract group showed chromatin marginalization,nissl substance dissolving,fuzzy boundary of nuclear membrane,as well as hell cells,and the total number of adenohypophysis cells reduced and the cells arranged in irregular.However,there were no apparent pathologic changes in different extracts groups.Conclusion Rhubarb water extract administration by long-term dose can reduce weight growth rate and result in pathologic changes of hypothalamic arcuate nucleus and adenohypophysis,while the different extracts can increase weight growth rate significantly and have little effects on the organizational structure ofhypothalamic arcuate nucleus and adenohypophysis.