Study On The Mechanism Of A New Injectable Hydrogel Loaded With NGF And Bone Marrow Mesenchymal Stem Cells To Promote The Repair Of Peripheral Nerve Injury

ObjectiveThe injectable hydrogel loaded NGF and BMSCs to repair long sciatic nerve defects in rats and discuss its possible repair effect.MethodsThe gel time of the chitosan-hyaluronic acid composite hydrogel cross-linking with genipin is measuring by the reverse test tube method.The NGF release test is that Genipin can change the release performance of hydrogel.The CCK-8 AND live/dead staining uesd to detect the cell viability.SFI is used to assess the recovery of rat sciatic nerve;Masson staining is used to assess the recovery of rat gastrocnemius atrophy;regenerated axons use HE staining to count;Relateive proteins expression use WB to measure.ResultsAt 37°C,the gelation time of the composite hydrogel detected by the test tube inversion method was about 10±2minutes.NGF sustained-release experiments show that as the concentration of genipin increases,Decreases the ngf explosive release,prolonged the sustained-release time,finally increase the sustained-release rate.CCK-8 and live/dead staining indicate that Genipin’s toxicity is acute and dose-dependent.Prolonging the cross-linking time can reduce its toxicity and increase cell survival and proliferation speed.In vivo animal experiments showed that the SFI recovery of rats with the new gel was similar to autologous,and was more better than the silicone tube.The results showed that the recovery of gastrocnemius muscle was improved,The diameter of muscle fibers and nerve regeneration axons plus,the proportion of collagen fibers minus.GAP-43 level was up,Nogo level was down.ConclusionGenipin cross-linked injectable hydrogel has good biocompatibility and low toxicity,can be a good carrier of NGF,prolonging the NGF release time and rate.The composite hydrogel can support the growth and release of MSC.As a filling material in the catheter,it promotes the damage and repair of long nerve defects in rats.