Prooxidant-Antioxidant Status of Dental Pulp and Lining of Oral Cavity of Rats with Experimental Iodine Deficiency and Insuline Resistance

The changes of microcirculation processes, cellular respiration, cell immune status, and metabolic disorders occupy a key place in the pathogenesis of periodontal diseases. According to the modern concepts, oxidative stress plays the main role in the non-specific link of such violations. It is proved that peroxidation affects not only on lipids, but primarily on plasma membrane proteins. It is known that thyroid dysfunction potentiates the inflammatory and degenerative processes of periodontal tissues. Not less changes appeared in the periodontal tissues under the conditions of insulin resistance (IR). Thus, oxidative stress in this case is the result of auto oxidation of glucose, non-enzymatic glycosylation, weakening of antioxidant protection due to increased intracellular glucose metabolism. That's why the aim of the research was to examine the prooxidant-antioxidant status of the dental pulp and lining of oral cavity in rats with iodine deficiency (ID) and IR. 60 male rats were involved in the study with body weight 150 – 180 g, and they were divided into two research groups for 30 animals in each. In rats of 1st research group ID was modeled, by keeping them on ID diet during 45 days. In the animals of 2nd research group the state of IR was modeled, by adding to drinking water of rats 10% solution of fructose during 8 weeks. For comparison, the corresponding parameters were determined in 30 intact animals (control group). The state of free lipid accumulation was assessed from the accumulation of conjugated dienes (DC) of polyunsaturated fatty acids and products that respond to thiobarbituric acid (TBA-RP) in dental pulp and lining of oral cavity. The level of peroxidation of proteins (POP) was determined from the number of products of their oxidative modifications (OMP) using spectrophotometry. The level of antioxidant defense system was assessed from the activities of catalase (C), superoxide dismutase, glutathione peroxidase (GP), glutathione reductase (GR), ceruloplasmin, and transferrin saturation by the blood serum iron. In animals with ID the mainly activation of lipid peroxidation was observed. So, in dental pulp and lining of oral cavity homogenates the increasing of DC in two times and in eight times, TBA-RP on 78.9% and on 70.7% respectively in comparison to control indices were noticed. Instead of it, free radical oxidation of proteins was intensified only in dental pulp (contents of ОМP was in 2.0-2.8 times bigger than analogical indices of intact animals). Oxidative changes in rats with IR were more significant. The contents of lipid peroxide products in examined tissues had become in 2.4-15.4 times bigger than control data. The same tendency was found in POP. So, contents of OMP in dental pulp and lining of oral cavity, homogenates in 4.0-7.3 times were higher than control data. During the comparison of peroxide processes between animals of 1st and 2nd research groups the increase of lipid and protein peroxide products on 40.8-93.8 % and in 2.6-5.7 times bigger respectively was found than analogic indexes in rats with ID. Activation of peroxidation was followed by changes of antioxidant defense. In animals with ID the activity of GP and GR in blood serum was lower on 42.1 % and on 76.5 % respectively to initial indices. In the same time, IR had lead to the activation of enzymes of glutathione system. But the activity of C in rats of 2nd research group was lower on 66.7 % than control data. So, it should be concluded, that ID leads to the activation of lipid peroxidation in dental pulp and oral lining homogenates on the background of suppression the activity of antioxidant defense. Modeling of IR was followed by more severe changes of oxygen dependent processes with simultaneously intensification not only lipids, but also proteins.