Effect of stigmasterol on lipopolysaccharide-induced neuroinflammation in mice

Neuroinflammation is the combination of the responses of all cells in the CNS. The long term regulation of inflammation can cause degeneration of neurons which lead to neurodegenerative disease such as Alzheimer's disease and Parkinson's disease. Since these diseases are incurable, many researches were conducted to find cure and prevention for these diseases especially Alzheimer's disease. Stigmasterol, a type of phytosterol, which can be found in many plants, possesses anti-cholesterol effect due to its structure similarity with cholesterol. However, there are not many studies on the effect of stigmasterol against neuroinflammation. In the present study, the effect of stigmasterol on LPS-induced memory impairments using the Morris water maze and probe tests was investigated. The efficacy of the prophylactic treatment of stigmasterol (10, 20 and 40 mg/kg, p.o.) were determined by measuring the escape latency, distance travelled, swimming speed and the average swimming time in target quadrant of LPS-induced ICR mice model. LPS (3 mg/kg, i.p.) was administered 3 days after the daily administration of stigmasterol (p.o.). The mice were given trainings for three days and Morris water maze test was conducted on the fourth day. On the last day, probe test was conducted to assess the spatial learning of the mice, in which the platform was removed. Results showed that there were no significant differences between the groups (p>0.05) in the escape latency. For the distance travelled as well as swimming speed, only the mice treated with 10 mg/kg of stigmasterol showed significant difference compared to LPS-induced mice (p<0.05). However, in probe test, the untreated mice showed a significant difference (p<0.05) compared to the normal and treated groups. The treated groups showed longer time spent in the target quadrant compared to the LPS-induced group. In conclusion, stigmasterol may have the potential in attenuating LPS-induced memory impairment and further studies are necessary to determine the mechanism of action.