title: Adenoviral-mediated glial cell line-derived neurotrophic factor gene transfer has a protective effect on sciatic nerve following constriction-induced spinal cord injury.
abstract: Neuropathic pain due to peripheral nerve injury may be associated with abnormal central nerve activity. Glial cell-line-derived neurotrophic factor (GDNF) can help attenuate neuropathic pain in different animal models of nerve injury. However, whether GDNF can ameliorate neuropathic pain in the spinal cord dorsal horn (SCDH) in constriction-induced peripheral nerve injury remains unknown. We investigated the therapeutic effects of adenoviral-mediated GDNF on neuropathic pain behaviors, microglial activation, pro-inflammatory cytokine expression and programmed cell death in a chronic constriction injury (CCI) nerve injury animal model. In this study, neuropathic pain was produced by CCI on the ipsilateral SCDH. Mechanical allodynia was examined with von Frey filaments and thermal sensitivity was tested using a plantar test apparatus post-operatively. Target proteins GDNF-1, GDNFRa-1, MMP2, MMP9, p38, phospho-p38, ED1, IL6, IL1β, AIF, caspase-9, cleaved caspase-9, caspase-3, cleaved caspase-3, PARP, cleaved PARP, SPECTRIN, cleaved SPECTRIN, Beclin-1, PKCσ, PKCγ, iNOS, eNOS and nNOS were detected. Microglial activity was measured by observing changes in immunoreactivity with OX-42. NeuN and TUNEL staining were used to reveal whether apoptosis was attenuated by GDNF. Results showed that administrating GDNF began to attenuate both allodynia and thermal hyperalgesia at day 7. CCI-rats were found to have lower GDNF and GDNFRa-1 expression compared to controls, and GDNF re-activated their expression. Also, GDNF significantly down-regulated CCI-induced protein expression except for MMP2, eNOS and nNOS, indicating that the protective action of GDNF might be associated with anti-inflammation and prohibition of microglia activation. Immunocytochemistry staining showed that GDNF reduced CCI-induced neuronal apoptosis. In sum, GDNF enhanced the neurotrophic effect by inhibiting microglia activation and cytokine production via p38 and PKC signaling. GDNF could be a good therapeutic tool to attenuate programmed cell death, including apoptosis and autophagy, consequent to CCI-induced peripheral nerve injury.
authors.affiliation: Department of Anesthesiology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan, R.O.C.
authors.forename: An-Kuo
authors.initials: AK
authors.lastname: Chou
authors.affiliation: Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan, R.O.C.; Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, R.O.C.; Laboratory of Medical Research, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan, R.O.C.
authors.forename: Ming-Chang
authors.initials: MC
authors.lastname: Yang
authors.affiliation: Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, R.O.C.
authors.forename: Hung-Pei
authors.initials: HP
authors.lastname: Tsai
authors.affiliation: Department of Pathology, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan, R.O.C.
authors.forename: Chee-Yin
authors.initials: CY
authors.lastname: Chai
authors.affiliation: Institute of Biomedical Science, National Sun Yat-sen University, Kaohsiung, Taiwan, R.O.C.
authors.forename: Ming-Hong
authors.initials: MH
authors.lastname: Tai
authors.affiliation: Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, R.O.C.; Department of Neurosurgery, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan, R.O.C.
authors.forename: Aij-Li
authors.initials: AL
authors.lastname: Kwan
authors.affiliation: Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan, R.O.C.; Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, R.O.C.; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, R.O.C.
authors.forename: Yi-Ren
authors.initials: YR
authors.lastname: Hong
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D017209:Apoptosis; D015870:Gene Expression; D015316:Genetic Therapy; D005822:Genetic Vectors; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000096:biosynthesis / Q000235:genetics*; D057809:HEK293 Cells; D006801:Humans; D006930:Hyperalgesia / Q000628:therapy; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D051745:Protein Kinase C-delta / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000378:metabolism* / Q000503:physiopathology; D012585:Sciatica / Q000628:therapy; D013119:Spinal Cord Injuries / Q000628:therapy*; D014161:Transduction, Genetic
chemical_list: D051100:Glial Cell Line-Derived Neurotrophic Factor; C497260:Prkcd protein, rat; C087857:protein kinase C gamma; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D020778:Matrix Metalloproteinase 2; C522363:Mmp2 protein, rat; D020780:Matrix Metalloproteinase 9; C572337:Mmp9 protein, rat