SOURCE:

Faculty: Health Sciences And Technology
Department: Medical Laboratory Science

CONTRIBUTORS:

Ogenyi, S. I.
Ngokere, A. A.

ABSTRACT:

Tobacco and alcohol use constitute major risk factors of oral lesions, due to their genotoxic and mutagenic effects on the buccal cavity epithelial cells. This result in altered cell nuclei morphology and functions generally referred to as nuclear changes. This study was aimed at evaluating nuclear changes and gene expression patterns of ki-67, p53 and p16 in the oral cavity of commercial bus drivers using tobacco and alcohol in Nnewi. One hundred and forty five (145) subjects, consisting of 105 tobacco and/or alcohol users (test group) and 40 tobacco and alcohol non users (control group) were recruited for this cross sectional study. Smear was obtained from the buccal cavity of each participant, processed and stained with the Papanicolaou staining method and Feulgen reaction. Two hundred cells were counted for each stained slide and the percentage of the various nuclear changes; pyknosis, karyorrhexis, karyolysis, karyomegaly, binucleate, broken egg nuclei, micro nuclei and nuclear halo determined. Repair index was calculated by the ratio of sum of karyorrhexis and karyolysis to binucleate and micronuclei (KH+KL/BN+MN). Expression patterns of ki-67, p53 and p16 were evaluated by immunocytochemisty, using ki-67and p53 monoclonal antibodies and p16 polyclonal antibody. Immunoreactivity was detected using exposed mouse and rabbit specific horseradish peroxidase/diaminobenzidine (HRP/DAB) immunohistochemistry detection kit, while immunoreactivity pattern was semi quantitatively scored. Comparisons of nuclear changes and gene expression patterns between and within groups were carried out using Kruskal walis H-test with p values of <0.05 considered significant. Associations between nuclear changes and repair index with gene expression patterns were analyzed using Spearman’s correlation test. Micronuclei were the most prevalent nuclear changes (100%) while broken egg nuclei were the least (15.2%). Nuclear changes were most prevalent amongst snuffers (33.42%). Statistically significant difference (p˂0.05) was observed when the median values of nuclear changes were compared in different study groups and with the control subjects. Similarly, prevalence of nuclear changes increased with age of subjects and the duration of tobacco use, whereas repair index decreased with increased prevalence. Ki-67, p16 and p53 were expressed in all study groups, with smokers having more expression pattern. There were little or no associations between the gene expression patterns with nuclear changes and repair index (r= -0.305). Smokers and alcohol drinkers co-expressed of ki-67, p16 and p53. Tobacco and/or alcohol use induced nuclear changes in the buccal epithelial cells of their users, with snuff inhalation slightly impacting more severe effect than cigarette smoking. Prolonged tobacco use increased nuclear changes. Buccal smear cytology, in conjunction with immunocytochemistry using ki-67, p53 and p16 panel will be an effective screening method for nuclear changes amongst tobacco and/or alcohol consumers and other high risk groups.