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Exogenous BDNF reduces NRTI-induced allodynia in mouse
Susan G. Dorsey, PhD, RN, Cynthia L. Renn, PhD, RN, and Sherrie Lessans, MS, RN. School of Nursing and Program in Neuroscience, University of Maryland, Baltimore, 655 West Lombard Street, Baltimore, MD 21201
One of the most debilitating neurological complications of HIV infection is painful peripheral neuropathy (PPN) associated with nucleoside reverse transcriptase inhibitors (NRTIs), a component of highly active antiretroviral therapy (HAART). The predominant symptom is excruciating unremitting pain that is resistant to traditional pharmacological treatments. Since withdrawal from HAART therapy is not typically recommended, strategies designed to reduce pain, for example the identification of new drug targets, are of great interest. Brain-Derived Neurotrophic Factor (BDNF) has recently been shown to be a potent modulator of nociception in the brainstem and spinal cord, thus we hypothesized that this molecule might be a potential candidate for therapy. To test our hypothesis, we generated a mouse model of NRTI-induced PPN. Briefly, we randomly assigned adult male C57BL/6J mice to receive 50 mg/kg/iv stavudine (d4T) or an equal volume of saline as a vehicle control. D4T-treated animals developed a robust mechanical allodynia by one day after drug injection that persisted to 28 days. Exogenous administration of high-dose BDNF intrathecally into the spinal dorsal horn (SDH; 1000 ng) and stereotaxically into the periaqueductal gray (PAG; 200 ng) one day after d4T injection significantly reduced d4T-induced mechanical allodynia by 30 minutes post-SDH and 3 hours post-PAG administration. Nocifensive behavior in control animals with d4T-induced allodynia that received an equal volume of intrathecal/stereotaxic saline remained unchanged. The analgesic effects of BDNF persisted for several days, after which d4T-induced allodynia returned. These results demonstrate that exogenous administration of supraphysiological doses of BDNF in the SDH and PAG alleviate d4T-induced mechanical allodynia in an animal model, suggesting that BDNF may be a potential candidate for the treatment of NRTI-induced PPN.
