Efeito do tratamento com vesículas extracelulares do leite bovino nas estruturas mineralizadas da maxila de camundongos.

Abstract

Osteoporosis, a disease resulting from increased bone resorption, is related to the weakening of bone tissue and the incidence of fractures. The increase in the rate of bone turnover occurs due to the imbalance in the activity of specific cells in the tissue that may result from several factors, such as estrogen deficiency. Drug therapies and food supplements that regulate bone tissue renewal are used to treat osteoporosis. In recent years, the extracellular vesicles of bovine milk (MEV) have demonstrated therapeutic potential in regulating bone tissue cells' activity. However, the consequences of its use on bone loss induced in the maxilla have not yet been demonstrated. Thus, this study aimed to evaluate the effect of oral administration of MEVs on bone and root parameters of the maxilla in mice submitted to ovariectomy and orthodontic tooth movement (OTM). Female C57BL / 6 mice were initially divided into 2 groups, receiving PBS (control) or MEV (treated) in drinking water. After 7 days, the animals were submitted to pseudo-surgery (SHAM) or ovariectomy surgery (OVX), and regrouped in (i) SHAM + PBS; (ii) OVX + PBS, (iii) SHAM + MEV; (iv) OVX + MEV. After 18 days of the surgical procedure, all animals underwent OTM. The results of bone parameters derived from OVX did not demonstrate significant changes in the alveolar bone microarchitecture of mice treated with MEV but significantly reduced the alveolar crest's height. When OTM induced bone remodeling, greater tooth movement was observed in untreated OVX animals, with no increase in the OVX group treated with MEVs. From the evaluation of cells in this tissue, an increase in osteoblasts and osteocytes caused by treatment with MEVs, previously reduced in the untreated OVX group, was observed, while the number of osteoclasts and the presence of bone markers such as RANKL and RANKL / OPG ratio were significantly smaller in OVX animals treated compared to those not treated locally and systemically. Besides, the significant increase in OVX control animals' odontoclasts was reversed in those who received treatment with MEV, indicating a reduction in the areas of inflammatory root resorption induced by OTM. After induction of tooth movement, inflammatory markers, such as TNF, were increased in the maxilla of the OVX groups regardless of treatment, but IL-33, which was increased in untreated OVX animals, was reduced after treatment with MEV. Systemic immune cells were reduced after treatment with MEVs, as evidenced by the total and mononuclear count. Thus, the treatment with MEVs demonstrated a positive modulation in the presence of bone cells in the tissue and in local and systemic markers associated with bone and maxillary remodeling, indicating its beneficial potential in the treatment of osteoporosis.