CORRELATIONS BETWEEN THE INDICATORS OF INFLAMMATION IN THE LIVER AND OSTEODYSTROPHIC CHANGES IN THE BONES IN RATS WITH HYPERVITAMINOSIS A
Authors: Galkin B. M. , Khodakov І. V. , Khromagina L. M. 
Published: September 2023

Background. The long-term therapy of dental diseases by the retinol especially in the cases of the use of high doses can lead to the significant accumulation of vitamin А in an organism, the results of which are such manifestations of the hypervitaminosis A signs as inflammation and development of liver fibrosis and activation of the destructive processes in the bones. Studying the correlation between indicators of the states of the liver and the bone system can be useful for monitoring the state of human bones through the liver indicators during long-term treatment with vitamin A, for example the dentistry diseases of different etiologies.
Objective. To investigate the correlation between biochemical indicators of inflammation and antioxidant protection in the liver and the density and the composition of tubular bones and vertebrae in rats under the conditions of high-dose vitamin A use against a periodontitogenic diet.
Materials and methods. Experiments were performed on male and female white Wistar rats aged 1 month. At the first stage, periodontitis was simulated with a periodontitogenic diet and the effect of this diet on the density of femur bones was determined. At the second stage, against the background of using this diet, hypervitaminosis A was simulated by introducing retinol at a dose of 8000 IU per 1kg of body weight for 56 days. The following parameters were determined: degree of atrophy of alveolar process of the jaws, density and content of the mineral (MC) and organic (OC) components of the femurs (FF) and lumbar vertebrae (LV), the activities of elastase, catalase, acid phosphatase, urease and the content of malondialdehyde (MDA) in liver tissues. Pearson’s correlation coefficients were calculated between liver and bone parameters.
Results. Keeping rats on a periodontitogenic diet led to a probable increase in F density: by 11.4–12.4%. The excess intake of vitamin A caused a decrease in the density of FF by 6.4–8.8%, LV by 9.1–9.2%, a decrease in the content of MC in FF by 8.4–12.9%, in LV by 11.2–12.7%, increase of OK in FF by 3.5–7.8%, in LV by 5.2–5.5%. The formation of hypervitaminosis A in liver tissues led to an increase in elastase activity by 39.9–51.3%, acid phosphatase activity by 23.0–23.2%, urease activity by 24.7–29.8%, MDA content by 34.6%–63.7%, a decrease in catalase activity by 3.1–3.8%. The highest correlation with bone state indicators was noted for elastase activity (r > 0.8) and MDA content (r > 0.6) in liver tissues for male and female rats in general. The correlation was negative with the density and content of the mineral component, and positive with the content of the organic component. Liver catalase activity was positively correlated with bone density and mineral content (r >0.7) only in males. Liver acid phosphatase activity was negatively correlated with the density and content of the mineral component of femur bones (r > 0.6) in males.
Conclusions. The hypervitaminosis A formation against the background of a periodontogenic diet leads to a decrease in bone density due to the inhibition of mineralization and the activations of bone resorption, and to inflammation and oxidative stress in liver tissues. The reliable correlation between elastase activity, MDA content in liver and the bone state indicators in male and female rats was revealed. The activities of catalase and acid phosphatase in liver were reliably correlated with the bone parameters only in males.