Abstract

This study aims to investigate the effects of clausenamide on streptozotocin (STZ)-induced diabetes in rats. The diabetic rat model was established via an intraperitoneal STZ injection. The rats were randomly divided into five groups, the normal control group, the model group, the insulin treatment group, the high-dose clausenamide treatment group, and the low-dose clausenamide treatment group. Three months after drug administration, reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were carried out to measure the Cyclooxygenase-2 (COX-2) expression in the hippocampus of the rats in each group. The RT-PCR results indicate that the hippocampal COX-2 mRNA levels significantly increased in diabetic rats compared with those in the other groups. However, the hippocampal mRNA COX-2 levels in the clausenamide treatment groups significantly decreased, which indicates an inhibitory role of clausenamide on COX-2 mRNA in the diabetic rats. The immunohistochemistry results demonstrate that COX-2 expression in the hippocampus of the diabetic rats significantly increased, which suggests that an abnormal COX-2 expression is involved in the pathogenesis of learning and memory deficiencies, and that clausenamide exerts a protective role by inhibiting COX-2 expression in diabetic rats. Clausenamide has several protective effects on the brain injury induced by long-term diabetes, and significantly reduces diabetes-related learning and memory deficiency. The mechanism correlated well with the inhibition of COX-2 expression in the hippocampus.

Key words: Clausenamide, diabetes, hippocampus, cycloxygenase-2 (COX-2).