High consumption of Garcinia Kola may impair hippocampal morphology, memory and learning in albino mice model

Abstract

The use of various psychoactive substances can easily alter and modified the subtle chemical and electrical processes of the brain. Hence this study analyzed the effect of varying doses and duration of kolanut extract (KNE) on hippocampal morphology, learning and memory. Fifty albino mice were divided into five groups of ten mice each. Group 1 received 3.3 mg/kg of extract for 10days, Group 2 received 2.84 mg/kg of extract for 7days, Group 3 received 2.45 mg/kg of extract for 5days, Group 4 received 2.73 mg/kg of extract for 3days, Group 5 were treated with 5 ml/kg of distilled water for 10days. Memory and navigation skills were assessed with Radial Arm Maze and T Maze. The hippocampus was fixed after cervical dislocation for H&E and Cresyl Fast Violet Stain. The pyknotic index (PI) was calculated for each hippocampal subarea.Results revealed a significant (p<0.05) increase in time of group 1 and 2 mice with regards Radial Arm Maze and T Maze assessments. Group 2 rats, group 3 and group 4 mice showed no significant changes (p<0.05) in body weight. There was a significant (p<0.05) increase in Pyknotic index in group 1 and 2 rats both at the CA1 and CA3 subarea of hippocampus when compared to the other treatment groups (group 3–4) whose Pykonotic index appear to be similar to that of the control. The sections from groups 1–4 had distorted arrangement of the pyramidal cells with several of them being pyknotic with dark shrunken nuclei and abnormal clumping of cellular formation were observed. In conclusion, the present study showed that high dose and long-term consumption of KNE can inhibit hippocampal neurogenesis and hippocampus-dependent learning and memory. We recommend that the fundamental mechanism that explains the degeneration and inhibition of neurogenesis by KNE be fully elucidated in future studies.