RHAMNUS CATHARTICA (BUCKTHORN) HEPATOCELLULAR TOXICITY IN MICE

The toxicity of the plant Rhamnus cathartica was assessed in mice afte r the plant was identified as a potential cause of an idiopathic neuro logic disease in horses. Another member of the Rhamnaceae family, Karw inskia humboldtiana, is neurotoxic to mammals and birds and can induce hepatic degeneration and necrosis. To investigate the toxicity of R. cathartica, a 34-day feeding trial in mice was conducted using a compl ete rodent diet with 0, 5, or 25% added R. cathartica. No clinical sig ns or gross lesions were seen, and all major tissues were histological ly normal except the liver. The livers of mice fed R. cathartica had m arked hepatocellular swelling. Results from periodic acid-Schiff react ion staining and from electron microscopy confirmed that the swelling was due to deposits of monoparticulate glycogen (beta particles) in th e cytoplasm. Glycogen deposition is an uncommon toxic change in cells. Apparently, compound(s) in R. cathartica directly or indirectly inter fered with glycogen metabolism (either glycogenesis or glycogenolysis) . Mechanistic and chronicity studies with R. cathartica are needed to investigate the pathophysiology of the glycogen disturbance and to det ermine if hepatic injury progresses and if other organs will be injure d.