Apotransferrin induces changes in thermal and mechanical sensitivities after single ligature nerve constriction of the sciatic nerve

P.R. BRUMOVSKY; P.L. MUSOLINO; M.F. CORONEL; C.P. SETTON-AVRUJ; M.J. VILLAR

San Diego, USA

Congreso; Society for Neuroscience; 2004

Society for Neuroscience

Single ligature nerve constriction (SLNC) and Bennett neuropathic pain models have been used for the study of pain triggered by peripheral nerve injury. Pain behavior appears to be dependent on the degree of nerve constriction, being a medium SLNC the most effective  in inducing allodynia-like pain behavior (Brumovsky et al., 2004). In this study we have analyzed changes in thermal and mechanical pain behavior in animals following SLNC of the sciatic nerve and also after simultaneous SLNC and apoTransferrin (aTF) injection into the nerve. Animals were anaesthetized and their right sciatic nerves were constricted in 40-80% using a 3.0 silk suture over a thin strip of polyethylene surrounding the nerve. A group of animals was then also injected with 2 ml of aTF at 0.5 mg/ml into the nerve. Animals were tested for mechanical and thermal withdrawal thresholds before surgery and after 1, 3, 7 and 14 days using von Frey and Choi tests, respectively. The results showed a normal pain behavioral pattern before lesion and in contralateral footpad of experimental animals. Three days after SLNC, 65% of animals developed ipsilateral mechanical allodynia and 75% showed an increase in sensitivity to cold stimulation. Animals subjected to SLNC and treatment with aTF showed a significant decrease in mechanical and thermal allodynia. Preliminary experiments analyzing the expression of b-III-tubulin (b-III-tub) and myelin basic protein (MBP) after simultaneous SLNC and aTF injection into the nerve did not show any changes in the neural distribution of these molecules. These results confirm the appearance of allodynia after SLNC and suggest a protective function of aTF on pain generation in peripherally chronic nerve constricted animals.