Effects of shisha smoke inhalation on some long-term memory forms in adult male mice

Abstract

Background: Shisha is a flavoured tobacco designed to be smoked in a water-pipe, but it
effects on long-term memory has not been fully explored. This study was undertaken to
evaluate the effect of Shisha smoke inhalation on some long-term memory models in adult
male BALB/c mice. Methods: Twenty male mice were divided into 4 groups of five mice
each. Group I (control): fresh air; group II: exposed to bonged Shisha; group III: exposed to
unbonged Shisha; group IV: exposed to activated charcoal smoke only. Each group was
exposed for thirty minutes daily for seven weeks. Long-term memory was assessed using
elevated plus maze (EPM), novel object recognition test (NORT) and Barnes maze (BM).
Results: There was statistically significant decrease (P<0.05) in novel object recognition in
bonged Shisha group when compared with the control. There was statistically significant
increase (P<0.05) in spatial learning and memory in bonged Shisha group when compared with
control. There was statistically significant decrease (P<0.05) in acetylcholinesterase activity in
bonged Shisha group when compared with control, but there was no statistically significant
difference in anxiety related spatial memory in elevated plus maze when compared with the
control. There was also increased in necrosis of hippocampal cells in bonged Shisha group and
slight necrosis in unbonged and activated charcoal smoke when compared to control mice.
Conclusion: The outcomes of this study suggest that bonged Shisha smoke is neurotoxic to the
brain because of combined effect of various toxicants emanating from different Shisha smoke
constituents used in the set-up.