Detecting structural and functional mitochondrial abnormalities in periodontal tissues using an experimental periodontitis model

Abstract

BACKGROUND: Recently, more and more evidence has emerged indicating that mitochondrial dysfunction plays an important role in the development and progression of inflammatory diseases of the oral cavity such as periodontitis, pulpitis. AIM: To evaluate structural and functional disorders in the mitochondria of periodontal tissues in an experimental model of periodontitis in laboratory rats. METHODS: Male white Wistar rats weighing 221 ± 7.5 g at the age of 4 months were used in this work. The animals were divided by simple randomization into two groups, 10 animals in each: group 1 – intact (control group); Group 2 – rats with simulated periodontitis. Experimental periodontitis in rats was modeled using the ligature method by sewing a polyfilament non-absorbable thread into the gum in the area of the mandibular incisors. The adequacy of the reproduced animal model of periodontitis was assessed using histological analyses. The following molecular genetics and biochemical parameters were assessed: damage to nuclear DNA (nDNA) and mitochondrial DNA (mtDNA), copy number and degree of heteroplasmy of mtDNA, expression of mitochondrial genes, as well as levels of hydrogen peroxide (H2O2), reduced glutathione (GSH) and malondialdehyde (MDA). RESULTS: The work shows that in the resulting model of experimental periodontitis, histological changes in periodontal tissue were identified, which indicated the formation of periodontitis in animals. The results of the analyzes showed that in animals on the 14th day after the application of the ligature, an increased level of damage and mtDNA heteroplasmy was recorded in the periodontal tissue, compared with the control group. In these same animals, a decrease in the expression level of mtDNA genes involved in ATP synthesis was observed. At the same time, a decrease in the level of GSH was recorded in the periodontal tissue, while the levels of H2O2 and MDA were increased compared to control animals. CONCLUSIONS: Structural and functional disorders were revealed in the mitochondria of periodontal tissues in an experimental model of periodontitis in laboratory rats. Thus, the development of new strategies for assessing mitochondrial function in periodontitis may help in the diagnosis and treatment of this disease, as well as its complications.