Evaluation of micronuclei count in exfoliated buccal mucosal cells amongst different age groups of normal healthy individuals: a quantitative study

Background: Micronuclei (MN) are a small additional nucleus and are readily identifiable by light microscopy. Biologically, MN is the chromosome fragments or whole chromosomes that lag behind at anaphase during nuclear division. MN occurs due to genetic damage of the cell and the MN scoring is the indicator of the genetic damage. But, it has been shown by various studies that MN formation is not always related with genetic damages and may be developed from the physiological damage of double stranded DNA break when a cell enters from G0 to G1 phase of the cell cycle. Therefore simple presence of MN may not indicate any disease as this may be seen even in normal healthy cell. Only high MN count may be suggestive of a genetic damage. Thus MN1 counting in normal healthy individuals can be used to supervise genotoxicity, biomonitoring of diseases, screening of preneoplastic diseases and identification of high risk patients. Objectives: • To compare total number of micronuclei and number of cells with micronuclei in exfoliated buccal mucosal cells amongst different age groups of normal healthy individuals. • To determine a normal range of total number of micronuclei and number of cells with micronuclei in exfoliated buccal mucosal cells amongst different age groups of normal healthy individuals in the studied population. Methods: This study was conducted on normal healthy individuals (n=500) age ranged from 18-70 years. Based on age normal healthy individuals were categorized into 5 age groups: Group A: 18-30 years; Group B: 31-40 years; Group C: 41-50 years; Group D: 51-60 years and Group E: 61-70 years. Each age group comprised n=100 normal healthy individual. The exfoliated cytosmears prepared from oral buccal mucosa of normal healthy individuals and stained with Papanicolaou (PAP) technique. We calculated the total number of MN (TMN) and number of cells with MN (CMN) per normal healthy individual since some cells had multiple MN. Results: The mean of TMN found were increased with increase in age and this difference was statistically significant. (p= 0.007) The mean of CMN also found were increased with increase in age. However, statistical test did not show any significant difference amongst them. (p= 0.071) In the normal healthy individuals, the normal range for TMN and CMN was 1 to 12 and 1 to 10 respectively. Conclusions: There is an increase in total number of MN (TMN) and number of cells with MN (CMN) with increasing age.