| Background and objectivePeripheral nerve injury is a challeng for surgeons. The most severe type of nerve damage is complete transection, which can result in neuropathic pain, loss of sense and motor function. The regeneration process of injured nerve is very slow. And the tissue adhesion usually leads to aweful prognosis. At present, the traditional suturing is the golden method for repairing the injured nerve. However,the outcome of functional restoration is not as good as expected. As a foreign body,the suture can inevitably cause inflammatory response and the formation of scar,which eventually affect the results. Recently, a new non-suture tissue bonding technique, called Photochemical Tissue Bonding(PTB), has been successfully used in repairing wound of skin, tendon, blood vessel and other tissues. Studies have demonstrated that PTB can easily repair the injured sciatic nerve with better regeneration and function recovery of lower limb compared with suturing,. As a new biological material, small intestinal submucosa(SIS), is widely applied for tissue repairing because it is non-immunogenic and can promote the cell proliferation. In this study, we aim to evaluate effect of PTB on repairing sciatic nerve in a complete nerve transection rat model.Methods1 In vitro experiment(selecting the appropriate light dose): 18 sciatic nerves taken from WISTAR rats were randomly divided into three groups, and then wraped with small intestinal submucosa. Rose bengal was appied to the both ends followed by illumination with 532 nm wavelength laser.at different fluences of 25, 50 or 100 J/cm2 in three groups. After irradiation, nerve tension were measured by tensiometer.2 In vivo experiment(evaluating the effect of PTB on repairing peripheral nerve):after harvesting sciatic nerve from rats’ thigh, samples were treated with suture(n=18),PTB(n=18), PTB+SIS(n=18) respectively. Adhesion, inflammatory response and scar formation of the injured nerve tissue were assessed The expression of S100 protein was assessed. Gastrocnemius of each animal was weighed after treatment and the degree of myophagism was evaluated. The recovery of nerve function was evaluated by sciatic nerve function index(SFI).Results1 In vitro experiments: The nerve strength in 100J/cm2 group was significantly higher than that in 25 J/cm2 group(P<0.01), and there was no obvious difference between 50J/cm2 and 25J/cm2 groups.2 In vivo experiments: 12 weeks post surgery, mild tissue adhesion was observed surrounding the damaged nerve in PTB group, but less than the suture group.There was no adhesion in PTB+SIS group. Obvious inflammatory cell infiltration was observed in suture group at 3 days after treatment while the inflammatory reaction and adhesion were significantly reduced in PTB and PTB+SIS group. 12 weeks after treatment, the gastrocnemius weight ratio in PTB and PTB+ SIS group were dramatically higher than that in suture group(P<0.05); The immunohistochemistry of S100 expression was positive in all three groups at 12 weeks, but the expression of S100 in PTB and PTB+SIS group was higher than that in suture group; 4 weeks after surgery, the SFI had no significant difference among all the three groups, However,the SFI in the PTB group was higher than the suture group in 8 and 12 weeks post surgery. The SFI in PTB+SIS group was higher than other groups, and the difference was statistically significant(P< 0.01).ConclusionsPTB can be successfully used in repairing sciatic nerve injury, and has more advantages than the traditional suturing, attributing to less inflammatory reaction and scar formation, which deserves further invastigation for other tissues which is noteasy to fix by suturing. |
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