Effects of crocin on spatial or aversive learning and memory impairments induced by lipopolysaccharide in rats

Abstract

Objective: Neuroinflammation and oxidative stress play essential roles in the pathogenesis and progression of neurodegenerative diseases, such as Alzheimer's disease. Crocin, main active constituent of Crocus sativus L. (saffron), possesses antiinflammatory, anti-apoptotic and anti-oxidative capacity. The aim of the present study was to investigate the neuroprotective effect of crocin on lipopolysaccharide (LPS)-induced learning and memory deficits and neuroinflammation in rats. Materials and Methods: The animals were randomly classified into four groups, including control, LPS, crocin 50 and crocin 100. The rats were treated with either crocin (50 and 100 mg/kg) or saline for a week. Later, LPS (1 mg/kg, i.p.) or saline was administered, and treatments with crocin or saline were continued for 3 more weeks. The behavioral tasks for spatial and aversive memories were performed by the Morris water maze and passive avoidance tasks from post-injection days 18 to 24. Furthermore, the levels of interleukine-1 beta, lipid peroxidation and total thiol were assayed in the hippocampus and cerebral cortex. Results: Our results demonstrated that treatment of LPS-treated rats with crocin decreased the escape latency in the Morris water maze and increased the time spent in the target quadrant in the probe trial. Moreover, crocin increased step-through latency in the passive avoidance test. However, there was no significant difference in the oxidative and neuroinflammatory responses among the experimental groups. Conclusion: Pretreatment with crocin attenuates spatial or aversive learning and memory deficits in LPS-treated rats.