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Intrathecal lentivirus-mediated transfer of interleukin-10 attenuates chronic constriction injury-induced neuropathic pain through modulation of spinal high-mobility group box 1 in rats . BACKGROUND Neuropathic pain is a complex state of chronic pain that is usually accompanied by peripheral and central nervous system damage or dysfunction . Previous studies have indicated that neuroinflammation in the spinal cord is an important contributor to neuropathological and behavioral abnormalities . A series of early inflammatory markers , such as IL-1 , TNF-α , and IFN-γ , and advanced inflammatory markers , such as high-mobility group box 1 ( HMGB1 ) , are involved in neuroinflammation . STUDY DESIGN A randomized , double blind , controlled animal trial . OBJECTIVE In this study , a lentivirus delivering human IL-10 ( LV/hIL-10 ) was administered intrathecally to determine the effects of IL-10 on allodynia and hyperalgesia in a chronic constriction injury-induced ( CCI ) rat model of neuropathic pain . METHODS Sprague-Dawley rats weighting 260 - 320 g were randomly divided into 4 groups . Group Sham ( Sham ) , Group CCI±Normal Saline ( NS ) , Group CCI±LV/hIL-10 ( LV/hIL-10 ) , and Group CCI±LV/control ( vector ) . Rats in each group were intrathecally delivered with NS , LV/control , or recombinant vector LV/hIL-10 in a total volume of 10 μl . Paw withdrawal mechanical thresholds ( PWMT ) and paw withdrawal thermal latency PWTL were measured one day before CCI ( baseline ) and 0 , 3 , 7 , 14 , and 28 days after intrathecal administration . Cerebrospinal fluid ( CSF ) samples were collected during surgical plane anesthesia and the collected CSF samples were used to assay for human IL-10 , rat IL-1β , rat IL-6 , and rat TNF-α by enzyme-linked immunosorbent assay ( ELISA ) . Animals were sacrificed and the L4-5 lumbar segment of the spinal cord was removed for determination of green fluorescent protein ( GFP ) expression . Immunohistochemical analysis was performed using anti HMGB1 antibodies and the expression of HMGB1 protein in the spinal cord was determined by western blot analysis after intrathecal delivery ( n = 8 each ) . RESULTS The results show that intrathecal LV/hIL-10 reverses enhanced pain states . Moreover , the increased level of HMGB1 exhibited in a late stage of CCI was inhibited by exogenous overexpression of hIL-10 in the CCI model . Expression of HMGB1 , RAGE , and pAkt were lower in CCI-induced rats treated with LV/hIL-10 than in those treated with LV/control ( vector ) or saline ( NS ) . Our results showed that IL-10 inhibits activation of the inflammatory HMGB1-RAGE pathway in the CCI rat model . LIMITATIONS Further experimental investigations are needed to clarify the specific biological roles played by HMGB1 in IL-10-mediated regulation of neuropathic pain . CONCLUSION Our results indicate that intrathecal lentiviral-mediated transfer of IL-10 attenuates CCI-induced neuropathic pain in rats . The anti-thermal hyperalgesia and anti-mechanical allodynia may be partly attributable to the decreased expression of HMGB1 and inhibition of HMGB1-RAGE pathway .
61563
Intervention_Pharmacological
interleukin-10
61564
Outcome_Physical
chronic constriction injury-induced neuropathic pain