DESENVOLVIMENTO DE NOVO MODELO EXPERIMENTAL DE DOR NEUROPÁTICA BASEADO EM LIGADURA DO RAMO SURAL DO NERVO ISQUIÁTICO

Abstract

Neuropathic pain is initiated or caused by a primary lesion or dysfunction in the nervous system. In 1988 Bennett and Xie developed the classic model of neuropathic pain by chronic constriction of the sciatic (CCS). However the CCS model causes a significant motor deficit, which may interfere with the results. This study was conducted in order to developing a neuropathic pain model with minimal alteration of motor function of the affected limb. A total of 18 Wistar rats were divided into two groups. The first underwent CCS surgery and the second group was submitedto surgical ligation of the Sciatic Nerve Sural Branch (LSB). The mechanical pain sensitivity was measured using the von Frey test. Motor function was evaluated by footprint test. At the end of the experiments the animals were euthanized and gastrocnemius muscles were removed for histological analysis. Our results indicated that animals submitted to LSB developed hyperalgesia equivalent to that observed in the CCS model when evaluated in von Frey test. Additionally the footprint test indicated that the LSB group had levels of motor impairment significantly lower than those of group CCS. Histological analysis showed that LSB produced a lower level of gastrocnemius muscle atrophy compared to the CCS. Thus our results suggest that the model LSB is as efficient as the CCS in the development model of neuropathic pain. However our model produces motor impairment significantly lower than that established by the CCS.