Does Nigella sativa oil prevent ketamine induced spatial memory impairment? An experimental study in male Wistar rats

Background: Spatial memory impairment has significant negative influence on both survival and quality of life. Nigella sativa oil (NiSO) has been investigated for its potential to reduce memory impairments in various experimental models. Objectives: To assess the effects of NiSO on ketamine induced working and reference memory impairment in male Wistar rats. Methods: This experimental study was conducted from March 2020 to February 2021 in the Department of Physiology, after obtaining ethical approval from the Institutional Review Board of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. For this purpose, 60 male Wistar rats were divided into normal memory (normal saline 5 ml/kg for 26 days), impaired memory (ketamine 15 mg/ kg during acquisition phase) and experimental (treated with NiSO 1 ml/kg for 26 days and ketamine 15 mg/kg during acquisition phase) groups. All groups underwent Radial arm maze (RAM) and Morris water maze (MWM) tests. Variables were working memory error (WME, re-entry into already visited arm) and reference memory error (RME, entry into non-baited arm) in RAM along with escape latency (EL, the moment of a rat’s entrance into the water upto it’s arrival at the platform) and target crossing (TC, number of crossing of the quadrant from where the platform was removed) in MWM. Data were expressed as mean±SEM and statistically analyzed with ANOVA followed by Bonferroni post-hoc test, where p≤0.05 was considered as significant. Results: Significantly (p≤0.001) higher WME and RME as well as significantly (p≤0.001) delayed EL and reduced TC were found in memory impaired rats when compared to normal memory rats. However, significantly (p≤0.001) lower WME and RME as well as significantly reduced EL (p≤0.001) and higher frequency of TC (p≤0.001) were observed in experimental rats, when compared to memory impaired rats. Moreover, these variables were almost similar in the experimental rats, in comparison to, those of normal memory rats except significantly (p≤0.01) higher TC in MWM test. Conclusions: NiSO prevented working and reference memory impairment as well as enhanced reference memory in rats. J Bangladesh Soc Physiol 2025;20(1): 19-31