Tiam Mana Saffari

193 FUNCTIONAL MOTOR RECOVERY OF STEM CELLS DELIVERED TO NERVE GRAFTS 9 Nonsurvival procedure At 12 and 16 weeks, ten rats of each group underwent a non-survival procedure. Anesthesia was induced by isof lurane, followed by intraperitoneal injection of Ketamine (80mg/kg) and Xylazine (10mg/kg) and maintained by additional doses of Ketamine (40mg/kg). Compound Muscle Action Potentials (CMAP) - Aminiature bipolar electrode was clamped around the sciatic nerve proximal to the nerve graft. One ground electrode was placed in surrounding musculature and two recording electrodes were superficially placed in the anterior tibial muscle. The CMAP was measured using a VikingQuest portable electromyelogram (Nicolet Biomedical, Madison, WI). A non-recurrent single stimulation with a duration of 0.02ms at an intensity level of 2.7mA was applied. Maximal amplitude measurements were obtained bilaterally 33,34 . Isometric Tetanic Force (ITF) - The ITF was measured bilaterally per the protocol of Shin and colleagues 35 . The peroneal nerve and tibial muscle were exposed and the hind limb was secured to a testing platformwith K-wires through the femur and ankle. The tibial tendon was secured to a clamp in anatomical position and attached to a force transducer (MDB-50; Transducer Techniques, Temecula, CA, USA) whose signals were processed using LabView (National instruments, Austin, Texas). A miniature electrode (Harvard Apparatus, Holliston, MA, USA), stimulated by a bipolar stimulator (Medtronic, Minneapolis, MN, USA) was clamped around the peroneal nerve branch of the sciatic nerve. The muscle tension and the stimulator frequency were optimized after which the maximal ITF was obtained. The tibial muscle was kept moist with warm saline. Wet tibial muscle mass - Rats were euthanized with an overdose of pentobarbital (Fatal Plus, 390 mg/mL, Vortech, Dearborn, MI, USA) intraperitoneally. Tibial muscles were harvested bilaterally and wet muscle mass was determined after removing the tendon. Histology - A three millimeter segment of both peroneal nerves of all rats were collected and placed into Trumps solution. Specimens were processed with 0.1M Phosphate Buffer, 1% Osmium tetroxide in buffer, graded series of alcohol and acetone. The samples were infiltrated in a 50%, 75% and finally 100% epoxy resin and polymerized