A Thirteen-week Oral Dose Subchronic Toxicity Study of Isaria sinclairii in Rats

Isaria sinelairii (IS) was orally administered at doses of 0, 0.04, 0.2, and 1 g/kg/day over a 13-week period. There were no observed clinical signs or deaths related to treatment in all the groups tested. Therefore, the approximate lethal oral dose of I. sinclairii was considered to be higher than 1 g/kg in rats. Throughout the administration periods, no significant changes in diet consumption, ophthalmologic findings, organ weight, clinical pathology (hematology, clinical chemistry, coagulation, and urinalysis) or gross pathology were detected. Minor changes were found in hematological parameters for the 0.04 g/kg/day and 0.2 g/kg/day IS treated groups (triglyceride reductions of $20.1{\sim}46.6%$ and platelet increases), but all changes were within physiological range. Microscopic examination failed to identify any treatment-related histopathologic changes in the organs of the IS-treated rats other than nuclear enlargement (cellular atypia) of the tubular regions in the medulla of the kidney in the high dose group. From these results, one can conclude that the no-observed effect level (NOAEL) of I. sinclairii is less than 0.04 g/kg/day in rats.