Transecção do menisco medial em camundongos promove mais dor e lesão que a sua retirada

Abstract

Abstract Osteoarthritis (OA) is a chronic degenerative joint disease characterized by loss of joint of function and disability, reduced with the quality of life. In humans, the lack of reliable and objective methods to evaluate the progression of OA limits their clinical study. Thus, animals are commonly used as model in an attempt to understand the pathophysiology of the disease and investigate new therapies. Considered one of the most experimental models of OA used, the mechanical instability of surgically induced experimentally reproduce the chronic trauma observed in human OA. Using models of surgical meniscectomy (meniscus removal) and destabilization of the medial meniscus (DMM) aimed to evaluate the difference in the development of OA in these experimental models and their response to different anti-inflammatory drugs. Swiss mice underwent surgery and the animals were sacrificed after 7 weeks, with daily assessment of joint pain (hypernociception). After sacrifice, the intra-articular lavage was colleted. The supernatant stored for evaluate cytokine-induced nitric oxide (NO). Histopathologic evaluation of the joints was performed according to the OARSI scores. Groups false-operated (Sham) were used for comparison. Meniscotomizados groups of animals receiving morphine (2 mg/kg, ip), naloxone (1 mg/kg, ip), indomethacin (2 mg/kg, sc), 1400W (0.5 mg/kg, sc), HOE-140 (1 mg/kg, sc) or anti-TNF (25-50 l) intraarticular. The hypernociception was recorded first and third hours after drug administration. Untreated group received vehicle only. Data were expressed as mean ± SEM, and ANOVA followed by Tukey test. The histopathological scores were expressed as median followed by Kruskal-Wallis. Statistical significance was set at P <0.05. In destabilization of the medial meniscus and meniscectomy, articular hyperalgesia increased significantly in the 16 days after surgery, compared to the sham group (false-operated animals). This hyperalgesia persisted in group destabilization of the medial meniscus until the 49th day of observation (P <0.05). The cellular influx was higher and articular lesions were more severe, particularly in tibial portion, destabilization of the medial meniscus group (P <0.05). Indomethacin, 1400W, HOE and morphine significantly reduced hypernociception, with reversal of the effect of morphine by naloxone. The analgesic effect of anti-TNF persisted for 7 days after administration. The levels of IL-1, TNF-α, IFN-γ and NO were undetectable. The destabilization of the medial meniscus is a more severe OA, involving the participation of cyclooxygenase, inducible nitric oxide synthase, bradykinin, opioids and TNF.