CORRELATION BETWEEN PERIODONTAL HEALTH INDICES AND PECULIARITIES OF CIRCADIAN RHYTHM IN BUCCAL EPITHELIAL CELLS

Abstract

There is a complex system of biological rhythms arranging the coordinationion of physiological functions and the environmental rhythms. The leading place it taken by the circadian rhythm, a 24-hour cycle that is a part of the body's internal clock. Circadian regulation of normal physiological and metabolic processes is carried out by the fluctuations in the expression of genes (clock-controlled genes (CCGs)) and the proteins they encode, which differ in each individual organ or tissue. The circadian rhythm of gene expression was detected in the basal cells of the oral epithelium, in the cells of ameloblasts and odontoblasts, cells of the dental pulp, cells of the periodontal ligament, osteoblasts and osteoclasts of the alveolar bone. However, so far little is known about the dependence of clock controlled gene expression on chronotype in buccal epithelial cells.
 The purpose of the study is to determine the expression level of the clock controlled genes Per1, Cry1, Bmal1 and Clock in the buccal epithelial cells of healthy people with different chronotype.
 Materials and methods. In order to achieve the goal we surveyed 14 people (7 men (50%) and 7 women (50%) aged from 36 to 45 years with a healthy periodontium without any somatic pathology or with compensated one. All participants signed an informed consent forms. The chronotype of the participants was determined by the Horn-Ostberg test modified by S.I. Stepanova and determined the mRNA expression of Clock, Bmal1, Per1 and Cry1 in buccal epithelium samples at 7:00 am and 7:00 pm in one day in the autumn-winter period.
 Results. The Per1 is better expressed early in the morning than in the evening, regardless of the chronotype (р1<0.05). The level of Clock expression is higher in the evening in both groups (р1<0.05). The difference between the indicators of the evening expression of the Clock in the two groups is statistically significant (р2<0.05). Bmal1 expression is higher in the evening, regardless of chronotype (р1<0.05). The Cry1 shows the same evening predominance among participants of both chronotypes, but it is not statistically significant.
 Conclusion. The study has revealed the correlation between chronotype and the evening expression of the Clock that is higher in people with the evening chronotype. Belonging to the morning or evening chronotype did not reveal any effect on the expression level of Per1, Bmal1 and Cry1.