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.

摘要：本研究通过评估牙槽窝愈合情况与骨强度，探究了电离辐射（ionizing radiation）的作用，以及非甾体抗炎药（non-steroidal anti-inflammatory drug）美洛昔康（meloxicam）对大鼠下颌骨骨生理状态的潜在辐射防护效应。将40只雄性Wistar大鼠随机分为4组（每组n=10）：对照组（CG）、单纯辐射组（IG）、单纯美洛昔康组（MG）、美洛昔康联合辐射组（MIG）。为MG组与MIG组大鼠灌胃0.2 mg/kg剂量的美洛昔康。随后，IG组与MIG组大鼠的下颌骨接受15 Gy剂量的电离辐射照射。上述操作完成40天后，拔除大鼠下颌第一磨牙，随后分别于拔牙后15天、30天各处死5只大鼠（每组各5只）。本研究分别采用微计算机断层扫描（Micro-computed tomography）与弯曲试验，对牙槽窝愈合情况及骨强度进行评估。拔牙后15天时，CG组与MG组的骨体积、骨体积分数及骨小梁厚度（trabecular thickness）均高于IG组与MIG组；而IG组的骨小梁分离度（trabecular separation）高于其余三组。拔牙后30天时，仅骨小梁分离度存在组间差异：IG组的骨小梁分离度高于CG组与MG组，而MIG组与其余各组无显著差异。IG组的骨强度低于CG组与MG组，而MIG组与其余各组无显著差异。综上，电离辐射可影响大鼠下颌骨的骨生理状态，延缓牙槽窝愈合进程并降低骨强度；此外，美洛昔康对牙槽窝愈合过程中的骨小梁分离度及骨强度均具有积极改善作用。