Histomorphological study of the effect of methanol leaf extract of Nicotiana tabacum (Tobacco) on substantia nigra par reticularis in Wistar rats.

BACKGROUND AND AIM: Smokeless or “Spit” are products of tobacco without combustion or pyrolysis at the time of use and the consumption of smokeless tobacco products continue to grow globally in form of dipping, snuffing, chewing and sniffing. The neurotoxic effect of tobacco is well documented.  The Substantia nigra par reticularis, an important basal nuclei structure sets the pattern for facilitation of voluntary movements of the body. This study assessed the effect of methanol leaf extract of Nicotiana tabacum (MLNT) on histomorphological studies of the substantia nigra par reticularis in Wistar rats. METHODOLOGY: Twenty male Wistar rats were divided into four groups (A-D, n=5). Group A was the control group treated with Tween 80 and Olive oil which served as vehicle for dissolution of MLNT. Groups B-D was treated with 200, 400 and 600 mg/kg MLNT respectively. Treatment was done for orally for four weeks. At the end of the experiment, the harvested brain tissue was weight before been processed for histological analysis. The body weight and the brain organosomatic index was computed and analyzes statistically using Statistical Package for social Science (IBM SPSS) Version 25.0. RESULTS: Results obtained for the body weight show no statistical significant difference between the initial and the final weight when compared to the control and also, the brain organosomatic index significant increase (p<0.05) in all treated groups when compared to the control, especially with MLNT (200 mg/kg). Histological and histochemical observations showed neurodegeneration in all treated groups when compared to the control. CONCLUSION: Finding from this studies revealed that MLNT could act as a potential neurotoxicant that can cause the acceleration of neurodegeneration in the substantia nigra par reticularis of Wistar rats thereby altered the coordination of motor activity.