Neural Mobilization (MOB) is a noninvasive method which has been clinically shown to be effective in reduction of pain sensitivity. This study aims to examine the effects of MOB on the pain sensitivity induced by chronic constriction injury (CCI) of sciatic nerve of rats and in animals with iontophoretic lesion of ventrolateral periaqueductal gray (vl PAG) by stereotactic technique. CCI was performed according to the technique described by Bennett and Xie (1988) and PAG lesion was performed as described in materials and methods. Both surgery were performed in adult male rats, subsequently the animals were submitted to ten MOB sessions initiated 14 days after CCI injury. In addition, we will also evaluate the locomotion behavioral through sciatic nerve functional index (SFI) and the maximal tetanic muscle force of tibialis anterior muscle using contractile function. After treatments with MOB and behavioral tests, the animals will be euthanized and tissues such as sciatic nerve, ganglia posterior roots (L4-L6) and PAG will be removed. The sciatic nerve will be used for analysis their ultrastructure through electron microscopy. Root ganglia (DRG's L4-L6) and PAG will be processed by Western blot test for the detection of opioid receptors, substance P and TRPV receptor. Our preliminary results concerning the test of the sciatic nerve functional index (SFI) showed an improvement in the treated group (CCI MOB) when compared to the untreated group (CCI). Similarly, our preliminary results on the maximal tetanic muscle showed a decrease of 52% in the untreated group (CCI) when compared with control animals (naïve) and an increase of 172% of the force in treated group (CCI MOB) when compared to the untreated group (CCI). However, animals with lesions in vl PAG and neuropathic pain when submitted to the treatment of Neural Mobilization showed a slight tendency of reversal in mechanical hyperalgesia. Thus, we suggest that Neural Mobilization reverses CCI-induced locomotor dysfunction, and increased 172% to maximum tetanic force of the tibialis anterior muscle compared to the untreated group. Moreover, there seems to be a strong influence of vl PAG in pain control, since the rats with lesions of the vl PAG not responded to treatments with Neural Mobilization.
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