Sinapic acid mitigates intracerebroventricular streptozotocin induced oxidative stress and neuro-inflammatory changes in rats

Abstract

Oxidative stress and inflammatory cytokines play an important role in progression of Alzheimer’s disease (AD). Sinapic acid, a natural phenolic compound has shown neuro-protection by amelioration of oxidative stress and neuro-inflammation. Here, we evaluated the effect of sinapic acid on oxidative stress and inflammatory cytokines in intracerebroventricular streptozotocin (ICV-STZ) sporadic model of AD in rats. Male Wistar rats (260 ± 20g), were administered ICV-STZ (3 mg/kg) and sinapic acid (10 and 20 mg/kg, orally) was administered for 21 days. Morris water maze and passive avoidance paradigm test was carried out on 0 and 21st days. On 21st day rats were sacrificed, levels of MDA, GSH, TNF-α and IL-1β were estimated in cortex and hippocampus. The expression of choline acetyltransferase (ChAT) was also assessed by western blot. On day 21, STZ produced memory impairment as evidenced by increased escape latency (p < 0.001), decreased time spent in target zone in Morris water maze. Sinapic acid attenuated the increased escape latency and improved the time spent in target quadrant at 20 mg/kg on 21st day (p < 0.05). STZ induced decreased transfer latency in passive avoidance paradigm was also significantly increased. STZ induced changes in levels of GSH and MDA were significantly normalised by sinapic acid. STZ induced levels of TNF-α and IL-1β were significantly (p < 0.05) attenuated by sinapic acid 20 mg/kg. Moreover, sinapic acid ameliorated the STZ induced decreased expression of ChAT in hippocampus. The results suggest that sinapic acid improves STZ-induced cognitive impairment by ameliorating oxidative stress and neuro inflammation in cortex and hippocampus.