The Effect of Cigarette Smoke Maintained at 10-32 ppm of Carbon Monoxide on Reference Memory and Count of Pyramidal Cells of the Hippocampus of Wistar Rats.

Abstract

AIM: Numerous works relating to memory had obtained several different results, some contrasting others. Hence, the need for the current work aimed at revealing the structural and functional implication of exposure to cigarette smoke at low concentration (10-32 part per million) on the memory system, the hippocampus in particular. METHOD: The methodology involved the use of reference time records obtained from Morris water maze task before and after the exposure to cigarette smoke. These reference time records served as indicators of the functional integrity of the hippocampus. Additionally, the pyramidal cell layer of CA1 and CA2 of the hippocampus of the male rats was photomicrographed and uploaded onto the manual counter of the image software, then counted into either normal appearing or pyknotic appearing cells. RESULTS: The results revealed a detoriation in the post exposure reference time records of the exposed male and female rats compared to the lower post exposure time records obtained among the control male and female rats. The cell counting revealed a significant increase in the population of both the normal and pyknotic pyramidal cells in the exposed male rats. CONCLUSION: These findings imply that cigarette smoke exposure at 10-32 ppm of carbonmonoxide disrupts reference memory in rats - mostly in females - and supports both neurogenesis and cell death in the pyramidal cell layers of CA1 and CA2 regions of the hippocampus of male rats