Toxic effects caused by rhubarb (Rheum palmatum L.) are reversed on immature and aged rats

Aim of the study: Rhubarb is generally used to people of broad age, but diverse responses of people at different age to rhubarb have been little clarified. In this study, an attempt was made to access the safety of rhubarb to both immature and aged rats to provide some references for its clinical usage. Materials and methods: The total extract of rhubarb was administered intragastricly to both immature and aged rats once a day and lasted for 5 weeks. Then histopathologic and biochemical examinations were performed. Results: No death was observed in immature rat groups, while 23.3% (21/90) subjects in aged rat groups died and most of the death cases were observed in the high-dosage (40 g kg(-1) of body weight per day od, counted on the quantity of crude material) group. The death rate between aged and immature rats was found of significantly statistical difference. Dosage-dependent histopathologic changes in kidney were observed in all the rhubarb-treated rats, principally involving the proximal tubules. Kidney changes in aged rats were severer than those observed in immature ones. Hepatic cells necrosis was occasionally observed in the middle- and high-dosage aged rat groups and minimal biliary hyperplasia was found in all the rhubarb-treated aged rats. Increased incidences of activated Kupffer cells and lymphocytic infiltration were found in all the rhubarb-treated rats. And dosage-dependent increase of interleukin 6 (IL-6) and notable increase of IL-8 was found in aged rat groups. Conclusions: The immature and aged rats showed reversed responses to the toxic potential of rhubarb extract. Elderly subjects were susceptible to the toxicity of high-dosage rhubarb, which drove rigorous consideration on rational use of rhubarb to aged people. (C) 2010 Elsevier Ireland Ltd. All rights reserved.