EFEITO DA DEXAMETASONA E DO CETOPROFENO NA OSTEOGÊNESE E NA RESISTÊNCIA ÓSSEA EM RATOS

Abstract

The treatment of several affections of the musculoskeletal system with anti-inflammatory drugs is very frequent. However, the effects of such drugs on boné neoformation and osseointegration after fractures or bone surgeriesare not well understood yet. This study aimed at evaluating the effect of ketoprofen (NSAID) and dexamethasone (SAID) on osteogenesis around a dense hydroxiapatite (DHA) implant in the left tibia and left parietal bone, and on the femur bone resistance. Fifteen fifty-day-old Wistar rats (Rattus norvegicus albinus) weighing on average 250±30 g were used. The animals were separated into three groups (n=5): control (CT); non-steroidal anti-inflammatoryl (NSAID); and steroidal anti-inflammatory (SAID). After anesthesia with IM ketamine/xylazine, a 3 mm cavity was made in the left parietal bone and in the proximal epiphysis of the left tibia. A DHA bioceramic was implanted in the tibia. The periosteum and the skin were repositioned by suturing their borders. The animals were treated subcutaneously during 30 days as follows: NSAID group: ketoprofen at the dose of 12/Kg/day; SAID group: dexamethasone, 0,10 mg/kg/day. The CT group received saline through the same route. All the animals received the same solid diet and water ad libitum. The daily water and ration consumption were calculated to evaluate the animals nutritional conditions. After 30 days of experiment, the animals wereeuthanized, and their femurs collected for the mechanical test, while their tibia and parietal sites were prepared for the histomorphometrical analysis. The daily consumption of water and ration was satisfactory, showing neither dehydration nor protein undernourishment. Microscopically, the SAID and NSAID groups showed a lower volume of neoformed bone. In addition, the NSAID and SAID group femurs required lower maximum force for complete rupture when compared with the CT group. It was concluded that ketoprofen and dexamethasone interfered with osteogenesis and decreased bone resistance by altering the bone tissue metabolism, mainly by inhibiting the COX-2 and decreasing prostaglandins. Therefore, the use of ketoprofen and dexamethasone after boné surgeries can compromise the stability and maintenance of implants.