title: Synergistic lithium chloride and glial cell line-derived neurotrophic factor delivery for peripheral nerve repair in a rodent sciatic nerve injury model.
abstract: BACKGROUND
  Restoring peripheral nerve function after long gap peripheral nerve damage is challenging. Lithium chloride has demonstrated neuroprotective qualities and therefore shows great potential therapeutic benefit for some neurodegenerative diseases. This study examined the synergistic combination of glial cell line-derived neurotrophic factor and lithium chloride and its effect on peripheral nerve regeneration in a rat sciatic nerve injury model.
  
  
  METHODS
  Polycaprolactone conduits with glial cell line-derived neurotrophic factor-loaded double-walled microspheres and local injections of lithium chloride, 1.5 or 2.5 mEq/kg body weight, were examined in a 15-mm rat sciatic nerve defect model. Eighteen Lewis male rats were divided randomly into control, 1.5-, and 2.5-mEq/kg lithium chloride injection groups. As an indicator of recovery, nerve sections were stained with S100, protein gene product 9.5 antibody, and toluidine blue.
  
  
  RESULTS
  Nerves stained with S100 and protein gene product 9.5 antibody demonstrated a significantly increased density of Schwann cells and axons in the 2.5-mEq/kg lithium chloride injection-treated groups compared with both the control and 1.5-mEq/kg lithium chloride injection-treated groups (p<0.05). At 6 weeks, histomorphometry revealed a significantly higher fiber density in the middle of the conduit for the 2.5-mEq/kg groups compared with the 1.5-mEq/kg group or the control group.
  
  
  CONCLUSIONS
  Polycaprolactone nerve guides with glial cell line-derived neurotrophic factor-loaded double-walled microspheres and local injections of lithium chloride, 2.5-mEq/kg, represent a potentially viable guiding material for Schwann cell and axon migration and proliferation for the treatment of peripheral nerve regeneration.
authors.affiliation: Pittsburgh, Pa. From the Departments of Plastic Surgery and Bioengineering and the McGowan Institute for Regenerative Medicine, University of Pittsburgh.
authors.forename: Yen-Chih
authors.initials: YC
authors.lastname: Lin
authors.forename: Sun Jung
authors.initials: SJ
authors.lastname: Oh
authors.forename: Kacey G
authors.initials: KG
authors.lastname: Marra
mesh_terms: D000818:Animals; D001707:Biopsy, Needle; D004195:Disease Models, Animal; D004357:Drug Synergism; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000494:pharmacology*; D007150:Immunohistochemistry; D018021:Lithium Chloride / Q000494:pharmacology*; D008297:Male; D009416:Nerve Regeneration / Q000187:drug effects*; D009431:Neural Conduction / Q000187:drug effects; D059348:Peripheral Nerve Injuries / Q000188:drug therapy* / Q000473:pathology; D011897:Random Allocation; D051381:Rats; D011917:Rats, Inbred Lew; D012016:Reference Values; D012584:Sciatic Nerve / Q000187:drug effects* / Q000293:injuries / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D051100:Glial Cell Line-Derived Neurotrophic Factor; D018021:Lithium Chloride
references.citation: Kokai LE, Ghaznavi AM, Marra KG. Incorporation of double-walled microspheres into polymer nerve guides for the sustained delivery of glial cell line-derived neurotrophic factor. Biomaterials. 2010;31:2313–2322
references.citation: Kokai LE, Lin YC, Oyster NM, Marra KG. Diffusion of soluble factors through degradable polymer nerve guides: Controlling manufacturing parameters. Acta Biomater. 2009;5:2540–2550
references.citation: Kokai LE, Bourbeau D, Weber D, McAtee J, Marra KG. Sustained growth factor delivery promotes axonal regeneration in long gap peripheral nerve repair. Tissue Eng Part A. 2011;17:1263–1275
references.citation: Makoukji J, Belle M, Meffre D, et al. Lithium enhances remyelination of peripheral nerves. Proc Natl Acad Sci USA. 2012;109:3973–3978
references.citation: Su H, Zhang W, Guo J, Guo A, Yuan Q, Wu W. Lithium enhances the neuronal differentiation of neural progenitor cells in vitro and after transplantation into the avulsed ventral horn of adult rats through the secretion of brain-derived neurotrophic factor. J Neurochem. 2009;108:1385–1398
references.citation: Chuang DM, Chen RW, Chalecka-Franaszek E, et al. Neuroprotective effects of lithium in cultured cells and animal models of diseases. Bipolar Disord. 2002;4:129–136
references.citation: Deumens R, Koopmans GC, Joosten EA. Regeneration of descending axon tracts after spinal cord injury. Prog Neurobiol. 2010;77:57–89
references.citation: Su H, Chu TH, Wu W. Lithium enhances proliferation and neuronal differentiation of neural progenitor cells in vitro and after transplantation into the adult rat spinal cord. Exp Neurol. 2007;206:296–307
references.citation: Kokai LE, Tan H, Jhunjhunwala S, Little SR, Frank JW, Marra KG. Protein bioactivity and polymer orientation is affected by stabilizer incorporation for double-walled microspheres. J Control Release. 2010;141:168–176
references.citation: Lin YC, Ramadan M, Van Dyke M, et al. Keratin gel filler for peripheral nerve repair in a rodent sciatic nerve injury model. Plast Reconstr Surg. 2012;129:67–78
references.citation: Ghaznavi AM, Kokai LE, Lovett ML, Kaplan DL, Marra KG. Silk fibroin conduits: A cellular and functional assessment of peripheral nerve repair. Ann Plast Surg. 2011;66:273–279
references.citation: Iwase T, Jung CG, Bae H, Zhang M, Soliven B. Glial cell line-derived neurotrophic factor-induced signaling in Schwann cells. J Neurochem. 2005;94:1488–1499
references.citation: Henderson CE, Phillips HS, Pollock RA, et al. GDNF: A potent survival factor for motoneurons present in peripheral nerve and muscle. Science. 1994;266:1062–1064
references.citation: Airaksinen MS, Saarma M. The GDNF family: Signalling, biological functions and therapeutic value. Nat Rev Neurosci. 2002;3:383–394
references.citation: Paratcha G, Ledda F. GDNF and GFRalpha: A versatile molecular complex for developing neurons. Trends Neurosci. 2008;31:384–391
references.citation: Yamada Y, Shimizu K, Nitta A, Soumiya H, Fukumitsu H, Furukawa S. Axonal regrowth downregulates the synthesis of glial cell line-derived neurotrophic factor in the lesioned rat sciatic nerve. Neurosci Lett. 2004;364:11–15
references.citation: Angelucci F, Aloe L, Jiménez-Vasquez P, Mathé AA. Lithium treatment alters brain concentrations of nerve growth factor, brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor in a rat model of depression. Int J Neuropsychopharmacol. 2003;6:225–231
references.citation: Azim K, Butt AM. GSK3β negatively regulates oligodendrocyte differentiation and myelination in vivo. Glia. 2011;59:540–553
references.citation: Cohen P, Goedert M. GSK3 inhibitors: Development and therapeutic potential. Nat Rev Drug Discov. 2004;3:479–487
references.citation: Arévalo JC, Chao MV. Axonal growth: Where neurotrophins meet Wnts. Curr Opin Cell Biol. 2005;17:112–115
references.citation: Freland L, Beaulieu JM. Inhibition of GSK3 by lithium, from single molecules to signaling networks. Front Mol Neurosci. 2012;27:14
references.citation: Young W. Review of lithium effects on brain and blood. Cell Transplant. 2009;18:951–975
references.citation: Nouri M, Rasouli MR, Rahimian R, Asadi-Amoli F, Dehpour AR. Lithium improves regeneration after sciatic nerve traumatic injury in rat. J Reconstr Microsurg. 2009;25:151