title: Electrical regulation of Schwann cells using conductive polypyrrole/chitosan polymers.
abstract: Electrical stimulation (ES) can dramatically enhance neurite outgrowth through conductive polymers and accelerate peripheral nerve regeneration in animal models of nerve injury. Therefore, conductive tissue engineering graft in combination with ES is a potential treatment for neural injuries. Conductive tissue engineering graft can be obtained by seeding Schwann cells on conductive scaffold. However, when ES is applied through the conductive scaffold, the impact of ES on Schwann cells has never been investigated. In this study, a biodegradable conductive composite made of conductive polypyrrole (PPy, 2.5%) and biodegradable chitosan (97.5%) was prepared in order to electrically stimulate Schwann cells. The tolerance of Schwann cells to ES was examined by a cell apoptosis assay. The growth of the cells was characterized using DAPI staining and a MTT assay. mRNA and protein levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in Schwann cells were assayed by RT-PCR and Western blotting, and the amount of NGF and BDNF secreted was determined by an ELISA assay. The results showed that the PPy/chitosan membranes supported cell adhesion, spreading, and proliferation with or without ES. Interestingly, ES applied through the PPy/chitosan composite dramatically enhanced the expression and secretion of NGF and BDNF when compared with control cells without ES. These findings highlight for the first time the possibility of enhancing nerve regeneration in conductive scaffolds through ES-increased neurotrophin secretion.
authors.affiliation: Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Jinghui
authors.initials: J
authors.lastname: Huang
authors.forename: Xueyu
authors.initials: X
authors.lastname: Hu
authors.forename: Lei
authors.initials: L
authors.lastname: Lu
authors.forename: Zhengxu
authors.initials: Z
authors.lastname: Ye
authors.forename: Quanyu
authors.initials: Q
authors.lastname: Zhang
authors.forename: Zhuojing
authors.initials: Z
authors.lastname: Luo
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D048271:Chitosan / Q000494:pharmacology*; D004553:Electric Conductivity; D004558:Electric Stimulation; D005786:Gene Expression Regulation / Q000187:drug effects; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D020932:Nerve Growth Factor / Q000235:genetics / Q000378:metabolism; D011108:Polymers / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012583:Schwann Cells / Q000166:cytology* / Q000187:drug effects* / Q000648:ultrastructure
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D008567:Membranes, Artificial; D011108:Polymers; D011758:Pyrroles; D012333:RNA, Messenger; C067635:polypyrrole; D048271:Chitosan; D020932:Nerve Growth Factor