Abstract: AIM: To investigate the effects of pioglitazone on the cognitive impairment induced by intracerebroventricular streptozotocin injection in mice and underlying mechanisms. METHODS: Streptozotocin (0.5 mg/kg) was intracerebroventricularly injected to induce cognitive impairment in mice. Pioglitazone was administered through a gastric tube every day for consecutive 20 days. The cognition function was evaluated by Morris water maze test and Y maze test. The Ach, AchE and ChAT of the hippocampus and cortex, and the blood glucose level in mice were determined. RESULTS: Pioglitazone (9 mg·kg^-1·d^-1, 18 mg·kg^-1·d^-1) significantly decreased the escape latency in visible platform test, increased the time spent in the platform quadrant in the spatial probe test, and significantly increased the correct number in Y maze test. Pioglitazone also significantly increased Ach levels and ChAT activity, and decreased AchE activity in hippocampus and cortex of mice. The difference in the level of blood glucose was not observed among groups. CONCLUSION: Pioglitazone may improve the cognition impairment induced by intracerebroventricular streptozotocin injection through the elevation of Ach levels that results from the decreased activity of AchE and increased activity of ChAT.

Key words: Pioglitazone, Streptozotocin, Cognitive impairment, Ach, AchE, ChAT