The Therapeutic Effect Of Carbon Nanotubes On Functional Rehabilitation Of Non-Completive Injury Of Sciatic Nerve

Background:The restoratations of nervous degenerative disease(e.g.,Alzheimer disease: Parkinson disease,motor neuronic disease),traumatic disease(the injury of brain,spinal cord and peripheral nerve),stroke(cerebral hemorrhage,cerebral infarction),infectious disease of nervous system and injury in postoperative of tumor all are revolved in nerve regeneration.But we have not found an efficient therapeutic method yet.Last years, along with the increasingly intensive research of carbon nanotubes technology,we find a potential application worth of carbon nanotubes to neurorestoration science,especially to the mechanisms of nerve cells growth in vitro.They appear to be implanted into in vivo to induce the regeneration and restoratation of injured cells of the notochord and brain and induce orientation growth of axons severed as a framework.Moreover,they can adjust the formation of axonal branches and complicated junctions of synapses.For a new biomaterial,if carbon nanotubes can indeed induce the neurorestoration,they would provide a new method to cure hemi-paralyses,paraplegia,peripheral nerve lesion and even nervous degenerative diseases.Objective:To investigate therapeutic effect of carbon nanotubes on functional rehabilitation of non-completive injury of sciatic nerve. Methods:The experiment 1:to investigate whether carbon nanotubes have therapeutic effect on functional rehabilitation of non-completive injury of sciatic nerve.24 adult Kunming mice were used and divided randomly into a control group and an experimental group.The unilateral sciatic nerves of all mice were damaged by a clamp.The mice in the control group were intraperitoneally given by physiological saline 0.5 ml/kg weight/ day and the mice in the treated group were intraperitoneally given by carbon nanotubes 1 mg/kg weight/day.The sciatic nerve function index(SFI) was accessed in the first day and the fifteenth day.The experiment 2:to investigate the dose and time effects of carbon nanotubes on the functional rehabilitation of non-completive injury of sciatic nerve.47 adult Kunming mice were divided into a control group and three experimental groups randomly.All unilateral sciatic nerves of all mice were non-completively damaged by the clamp.The physiological saline 0.5 ml/kg weight/day was given to the mice in the control group and the carbon nanotubes 1 mg/kg weight/day,0.5 mg/kg weight/day and 0.1 mg/kg weight/day were given to the mice in each experimental group respectively.SFI was accessed in day 1,7,10 and 15,respectively.At last,we want to know whether functionalized multiwalled carbon nanotubes can be found in injure sciatic nerve.Specimen of sciatic nerves was obtained 8 hours later when multiwalled carbon nanotubes being injected into abdominal cavity of mice and were observed by transmission electron micrographs.Results:In the first experiment,there was no significant difference of the SFI between two group in the first day(P=0.373)but the difference was significant in the fifteenth day(P=0.003).In comparison with normal saline treatment,functionalized multiwalled carbon nanotubes(1 mg / kg / day) significantly improved functional recovery following sciatic nerve injury.In the second experiment,we found the dose and time effects of carbon nanotubes on the functional rehabilitation ofnon-completive injury of sciatic nerve are significant.Dose effect:in comparison with normal saline treatment, functionalized multiwalled carbon nanotubes(0.1 mg / kg / day) have no obvious difference(P=0.16),functionalized multiwalled carbon nanotubes(0.5 mg/ kg / day,1 mg / kg / day) significantly improved functional recovery following sciatic nerve injury(P=0.002,P＜0.001).Time effect:SFI in day 7,10,15 have significant difference compared with day 1(P＜0.001),SFI in day 7 compared with in day 10 have no significant difference(P=0.276),SFI in day 15 have significant difference compared with in day 7, 10(P＜0.001,P=0.001).We also found multiwalled carbon nanotubes exist in endochylema of the Schwann cell of sciatic nerve in vivo by transmission electron micrographs.Conclusions:Carbon nanotubes can reach impaired sciatic nerve quickly and have therapeutic effect on functional rehabilitation of non-completive injury of sciatic nerve, and the effect is correlated with dose and time.