| Background: Ulcers caused by diabetes are refractory ulcers and are one of the most common complications of diabetes,often caused by diabetic microangiopathy and neuropathy.With the development of tissue engineering technology,the development of engineering scaffolds for autologous skin replacement has become a hot topic,and chitosan（CS）and collagen（Collagen,COL）scaffolds are a hot topic.When the two are used alone as scaffold materials,their practical application is limited due to some deficiencies.Astragalus polysaccharides（APS）can promote the angiogenesis of the wound and around the wound,and reduce the complications of blood vessels caused by diabetes.It has a clear therapeutic effect.Therefore,APS-CS/COL scaffolds were fabricated by freeze-drying method in this study.APS was loaded in CS/COL composite scaffold material.Objective: To characterize the synthetic material and place it on the wound of diabetic rats,and to observe the effect of APS-CS/COL scaffold on the healing process of diabetic rat wound in different ways.Methods: 1.Fabrication of APS-CS/COL and CS/COL scaffolds: 20 g/L chitosan solution and 3.55 g/L type I collagen solution were prepared with low concentration（0.2 mol/L）acetic acid solution as solvent.Astragalus polysaccharide and collagen w/w=1:1 were weighed and dissolved in collagen solution.A mixed solution containing 50 mmol/LMES（2-morpholinoethanesulfonic acid）,50 mmol/L NHS,and50 mmol/LEDC was prepared to cross-link APS-CS/COL.Taking the volume of type I collagen solution as the standard,add an appropriate amount of chitosan solution according to the volume ratio of 3:7,mix the two thoroughly,add an appropriate amount of cross-linking agent,and cross-link for 6 h at room temperature.After the cross-linking is completed,it is injected and milled,and then placed in a freezer at minus 20 degrees to wait for it to be fully frozen and solidified,and then freeze-dried for 12 hours without interruption.The CS/COL scaffold was made without adding astragalus polysaccharide but in the same way.2: Observation of the effect of APS-CS/COL and CS/COL scaffolds on the wound healing process of diabetic rats:APS-CS/COL and CS/COL were used for wound repair of diabetic skin defect model rats,respectively,and recorded as CS/COL,respectively.The COL group and the APS-CS/COL group,15 rats in each group,took 15 diabetic skin defect model rats without tissue engineering scaffolds for wound repair as the control group.On the 7th,14 th,and 21 st days after the operation,the general condition of the wound was observed with the naked eye,and the wound healing rate was calculated by Image J software;the new wound tissue of the rat was collected,and the morphology of the regenerated skin tissue of the rat was observed under a microscope after HE staining.Results: On the 7th day after operation,obvious inflammation could be observed in the wounds of the rats in the control group and CS/COL group,and a small amount of fibroblasts were seen under the microscope;no obvious inflammation was found around the wounds of the rats in the APS-CS/COL group.,a small amount of new granulation tissue can be seen in the center of the wound,and many fibroblasts can be seen under the microscope,and obvious signs of microvascular formation and tissue healing can be observed.On the 14 th day after the operation,the wounds of the rats in the control group and CS/COL group had scabs,there was inflammation,and the wound area was large.There were a large number of fibrocytes and collagen fibers in the dermis under the microscope;APS-CS/COL group The healing process of the wound surface was rapid,and a small area of ??unhealed was seen in the center of the circle.Microscopically,there were a small number of fibroblasts and a large number of compact collagen fibers in the new dermis,and skin appendages in the differentiation stage appeared.On the 21 st day after the operation,a small amount of epithelial growth was seen in the wounds of the rats in the control group and CS/COL group from the circumference inward,most of which were filled with granulation tissue,and the new white hair was sparse.The cortex was not fully differentiated and thick,and new blood vessels and cell appendages could be observed;the wounds in the APS-CS/COL group were filled with granulation tissue,and most of the original wounds had been replaced by epithelium,and many white new hairs were visible.It can be seen below that the structure of the new skin on the wound surface is similar to that of normal tissue,and the epidermis,dermis,new blood vessels,cell appendages and other structures are completely formed.The wound healing rates of the rats in the APS-CS/COL group were higher than those in the CS/COL group and the control group on the 7th,14 th,and 21 st days after operation（all P<0.05）.Conclusion: APS-CS/COL tissue engineering scaffold can significantly promote the repair process of skin defect wounds in diabetic rats. |
PDF Full Text Request