title: Functional effects of local administration of thyroid hormone combined with chitosan conduit after sciatic nerve transection in rats.
abstract: OBJECTIVE
  To assess the local effect of triiodothyronine (T3) on peripheral nerve regeneration in a rat model of sciatic nerve transection.
  
  
  METHODS
  Forty-five male healthy white Wistar rats were divided randomly into 3 experimental groups (n = 15): sham operation, control (CHIT), and T3 treatment (CHIT/T3). In the sham-operated group, the left sciatic nerve was exposed under anesthesia through a gluteal muscle incision and the muscle was sutured after homeostasis. In the CHIT group, the left sciatic nerve was exposed the same way and transected proximal to the tibioperoneal bifurcation, leaving a 10-mm gap. Each proximal and distal stump was inserted into a chitosan conduit, which was filled with phosphate buffered solution 10 μL. In the CHIT/T3 group, the defect was bridged using a chitosan conduit filled with T3 10 μL. Each group was subdivided into 3 subgroups of 5 animals each and studied 4, 8, and 12 weeks after surgery. Data were analyzed statistically by factorial analysis of variance and the Bonferroni test for pairwise comparisons.
  
  
  RESULTS
  Behavioral testing and sciatic nerve function study confirmed a faster and better recovery of regenerated axons in the CHIT/T3 group than in the CHIT group (P < .05). Gastrocnemius muscle mass was significantly larger in the CHIT/T3 group than in the CHIT group. Morphometric indices of regenerated fibers showed that the number and diameter of the myelinated fibers were significantly larger in the CHIT/T3 group than in the CHIT group. Immunohistochemistry showed that the locations of reaction to S-100 were clearly more positive in the CHIT/T3 group than in the CHIT group.
  
  
  CONCLUSIONS
  The response to local treatment showed that thyroid hormone influenced and improved the functional recovery of peripheral nerve regeneration.
authors: Assistant Professor, Department of Clinical Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran. Electronic address: r.mohammadi@urmia.ac.ir.
authors: Rahim
authors: R
authors: Mohammadi
authors: Keyvan
authors: K
authors: Amini
authors: Alireza
authors: A
authors: Yousefi
authors: Mehdi
authors: M
authors: Abdollahi-Pirbazari
authors: Abolfazl
authors: A
authors: Belbasi
authors: Farzaneh
authors: F
authors: Abedi
mesh_terms: D000287:Administration, Topical; D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology; D001672:Biocompatible Materials / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D048091:Guided Tissue Regeneration / Q000295:instrumentation* / Q000379:methods; D007150:Immunohistochemistry; D008124:Locomotion / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation / Q000473:pathology; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000502:physiology; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology*; D009929:Organ Size; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D019651:Plastic Surgery Procedures / Q000295:instrumentation / Q000379:methods; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology; D009418:S100 Proteins / Q000032:analysis; D012584:Sciatic Nerve / Q000187:drug effects / Q000502:physiology / Q000601:surgery*; D054457:Tissue Scaffolds; D014284:Triiodothyronine / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D001672:Biocompatible Materials; D009418:S100 Proteins; D014284:Triiodothyronine; D048271:Chitosan