Meloxicam as a Radiation-Protective Agent on Mandibles of Irradiated Rats

Abstract

This study evaluated the action of ionizing radiation and the possible radioprotective effect of the non-steroidal anti-inflammatory drug meloxicam on the bone physiology of rat mandibles by assessing the alveolar socket healing and bone strength. Forty male Wistar rats were divided in 4 groups (n=10): control (CG), irradiated (IG), meloxicam (MG), meloxicam irradiated (MIG). A dose of 0.2 mg/kg meloxicam was administered to MG and MIG. After this, IG and MIG were irradiated with 15 Gy radiation dose in the mandible. Forty days after the above procedures, the mandibular first molars were extracted and the animals were killed after 15 or 30 days (n=5). Micro-computed tomography and bending test were used to evaluate alveolar socket healing and bone strength, respectively. At 15 days, bone volume, bone volume fraction and trabecular thickness were higher in the CG and MG than in the IG and MIG; and trabecular separation was higher in the IG compared with the others. At 30 days, there was a difference only in trabecular separation, which was higher in IG than in CG and MG, and MIG did not differ from the others. Bone strength was lower in IG compared with CG and MG, and MIG did not differ from the others. In conclusion, the ionizing radiation affected the bone physiology of rat mandibles, delaying the alveolar socket healing and reducing the bone strength. Moreover, the meloxicam had a positive effect on the trabecular separation in alveolar socket healing and on the bone strength.

Radioprotective Effect of Sodium Selenite on Mandible of Irradiated Rats

“…Previous studies (3,15,(16)(17)(18) have sought to develop a model for induction of osteoradionecrosis in animals, through bone physiological changes with ionizing radiation; however, only a few have sought to evaluate means to prevent the development of the same. Moreover, although some experimental studies have studied the effect of radioprotective agents on the injuries of ionizing radiation (6,10,(19)(20)(21), their search was made with the goal to prevent or reduce acute complications of high doses of ionizing radiation.…”

“…Malignant lesions on head and neck are usually treated by a combination of surgery and radiotherapy with/without chemotherapy (1). Despite the increased survival rate of patients who make use of these modalities of treatment, still have considerable morbidity due to the deleterious effects of radiotherapy, which uses high doses of ionizing radiation, on regular cellular components, resulting in acute and/or chronic complications in the tissues of the craniofacial region (2,3).…”

“…After radiotherapy, the oral acute complications are generally reversible. However, delayed complications promote changeless damage to irradiated regions, such as bone tissue (3). The blood vessels of the periosteum injuries cause osteoblastic and osteoclastic activity decrease, and an increase of fibrotic and adipose tissues in the bone marrow, resulting in decreased cellularity and blood vessels (4).…”

“…In addition, befall formation of free radicals, destruction of endothelial cells, non-specific chronic local inflammation, microvascular thrombosis, fibrosis and, finally, osseous and tissue necrosis that results in tissue hypoxia, hypocellularity and hypovascularity (8,9). Consequently, due to metabolic and homeostatic alterations of bone tissue, it occurs damage in remodeling and bone healing, besides increasing susceptibility to bone infections (3).…”

“…In order to reduce toxic effects of ionizing radiation on healthy tissues, several studies have evaluated a variety of radioprotective agents (3,6,10,11). These agents may be act by the elimination of free radicals, behave as "sweepers" or indirectly by incentive of production of antioxidant enzymes (12).…”