Evaluation Of The Effect Of PRP On Peripheral Nerve Regeneration By Constructing Sciatic Nerve Small Gap Defect Model With Preservation Of Epineurium

Purposes:To evaluate the effect of platelet rich plasma(PRP)on peripheral nerve regeneration.Method:Twenty-eight New Zealand white rabbits were selected and randomly divided into groups A(n=7),B(n=21).The B group was subdivided into 3 subgroups,B1,B2,and B3 groups(n=7).Right-side sciatic nerve of rabbits were selected and made into the model.Group A is the control group in which gaps were filled saline;group B is the PRP group,and groups B1-B3 are followed by low concentration Group,medium concentration group,high concentration group,add different concentrations of PRP to small defects according to grouping.In the PRP group,PRP was injected locally every 2 weeks for a total of 3 injections.Model preparation:The rabbits were fixed in prone position after anesthetized,the right hip area is sterilized and exposed the sciatic nerve.According to our observation during the surgery,sciatic nerve of rabbit were presented as 4 nerve bundles,including two thick nerve bundles.in the middle which were performed into model and two thin bundles on the lateral which were incised when appear.Making a longitudinal incision on the epineurium of the model nerves and separate the nerve fiber from epineurium.The nerve fibers were cut under direct vision.Then a 2-3mm nerve gap were formed due to the retraction of the nerve fibers.Trimming 1mm on both sides to form a cdefect area of 5mm,and suture the epineurium.PRP preparation:Whole blood was collected from the central artery of rabbit ears,blood sample of group B1 was 10ml(1ml sodium citrate+9ml whole blood),group B2 was 15ml(1.5ml sodium citrate+13.5ml Whole blood),group B3 was 20 ml(2ml sodium citrate+18ml whole blood).After two-step centrifugation,2ml of PRP was preserved.Contract 0.02ml whole blood sample and 0.02ml PRP for platelet counting,the rest PRP was mixed with 10%calcium chloride in a ratio of 10:1 for activatingc.At about 12 weeks,the rabbits in each group were subjected to electrophysiological testing to obtain the rabbit composite nerve stem action potential,composite neuromuscular action potential,and nerve conduction velocity;for the rabbit sciatic nerve injury site,tissue section was performed and Luxol fast blue staining was performed.Thin sections were stained with luxal fast blue;gastrocnemius muscle and tibial anterior muscle were removed from each rabbit The wet weight ratio of the muscle was measured,the gastrocnemius muscle belly of the affected side was taken for Masson staining,and the composition ratio of muscle fibers and collagen fibers was evaluated under light microscope.Results:The results of electromyography showed that:group A did not lead to normal waveforms,only one rabbit in group B1 could record compound muscle action potentials,and only one rabbit in group B2 did not measure compound muscle action potentials in the rest of the rabbits.Compound muscle action potentials were measured.All rabbits in group B3 could record compound muscle action potentials.Wet-to-weight ratio:The wet-to-weight ratio of the target muscles in the B3 and B2 groups is greater than that of the A and B1 groups,and the difference between the groups is statistically significant,that is,the degree of denervation and reinnervation of the target muscles in the B3 and B2 groups is better than that of the A The muscle atrophy of group B1 and group B1 is also lighter than group A and group B1.There is no significant difference in wet weight ratio between group B3 and group B2(P>0.05).Therefore,it can be considered that the target muscle between the two groups is The degree of shrinkage and redemption are roughly the same.Musson staining results showed that the muscle fiber composition rate of B2 and B3 groups was higher than that of B1 and A groups(P<0.05).The number of myelinated nerve fibers in the B3 and B2 groups was significantly higher than that in the B1 and A groups by Luxal Fast Blue staining.Conclusion:Platelet-rich plasma has a promoting effect on the regeneration of peripheral nerve tissue.The main functions include 1.PRP can improve the quantity and quality of the regeneration of myelinated nerve fibers.2.PRP can improve the denervation and atrophy of target organs and promote the process of denervation.3.PRP can improve the EMG parameters of injured sciatic nerve.