Avaliação do desenvolvimento de lesões periapicais em ratas com osteoporose induzida

Abstract

Osteoporosis is a systemic condition characterized by reduced bone mineral density (BMD) and microarchitectural deterioration of bone tissue. The most common kind of Osteoporosis is found in the postmenopausal period. Among the factors that lead to a decrease in BMD during this period, estrogen deficiency stands out due to atrophy of the ovaries and increased oxidative stress generated by the production of reactive oxygen species. Oxidative stress is responsible for the occurrence of cellular damage and is closely related to the loss in bone density which occurs in osteoporosis. Studies have shown that some systemic conditions, such as osteoporosis, can alter the progression and severity of periapical lesions, because of decreased bone density and increased speed of reabsorption. Thus, the aim of this study was to evaluate the influence of osteoporosis on periapical lesions induced in rats. Twenty Wistar lineage rats were used on the study, divided into 2 experimental groups (n = 10): ovariectomized (OVX) and sham ovariectomized (sham). After 21 days, all animals were submitted to the periapical lesion induction procedures by endodontic opening of the mandibular first molar and exposure of the pulp to the oral environment by the end of the trial period. After 35 days from the date of induction of periapical lesions, the animals were euthanized. Estrogen level analyzes were performed, of oxidative stress in the liver (nitric oxide), and the measurement of the area of periapical lesions by digital radiography and femoral BMD and jaw tomography multislice. The data were submitted to the unpaired t test with significance level set at 5% (P <0.05). The results showed no statistical difference in the size of the periapical lesion between the OVX and SHAM groups. However, the levels of estrogen and uterine weight was significantly lower for the OVX group than for the SHAM, showing the model of osteoporosis. In addition, oxidative stress analysis showed that ovariectomy induced a significant increase of nitric oxide in the OVX group compared to the SHAM group. Regarding bone parameters, BMD in the condyle of the femur was significantly lower in the OVX group than in the SHAM group, but the jaw significant differences were found between the two groups. Although osteoporosis have influenced the level of nitric oxide and have had an effect on BMD of the femur in ovariectomized rats, the data revealed that the systemic condition did not change the size of periapical lesions induced in Wistar rats.