Clinical safety of collagen nerve scaffold with longitudinally oriented microchannels in bridging peripheral nerve defect / 中华显微外科杂志

Objective To evaluate the clinical safety of the collagen nerve scaffold with longitudinally oriented microchannels in bridging peripheral nerve defect.Methods Five patients with 8 peripheral nerve defects of 18 to 30 (mean,23.8) mm in length were involved in the pilot study and treated from July,2017 to March,2018,including 6 digital nerves and 2 medial antebrachial cutaneous nerves.The defects were repaired with the collagen nerve scaffold with longitudinally oriented microchannels independently developed.Routine therapy of prophylactic systemic antibiotics but no immunosuppressive drugs was given to all patients post-operatively.All patients were followed-up by regular review in the outpatient department combined with WeChat and telephone.The clinical safety of the nerve scaffold was preliminarily evaluated through observing the condition of the healing of the local wound and the whole body.The blood routine examineation and biochemical test were detected.The statistical analysis of the measurement data was performed by the analysis of variance of repeated measurement data,and the difference was statistically significant when P＜0.05.Results All patients were followed-up for 7 to 15 months (average,10 months).No adverse events such as infection,allergy,damage of liver and kidney function occurred.The operative incisions healed primarily,with no redness,exudation and rupture in the local area.There was no systemic symptoms such as fever,nausea,vomiting,skin itching,etc.The results of blood routine tests and biochemical tests were normal.The data of tests was compared,and the difference was not statistically significant (P＞0.05).Conclusion The preliminary study shows that it is clinically safe to bridge peripheral nerve defects with the collagen nerve scaffold with longitudinally oriented microchannels.

Repairment of 1 cm sciatic nerve defect by bone marrow mesenchymal stem cell of adult rat combined with tissue-engineered artificial nerve / 器官移植

Objective To discuss the effect of bone marrow mesenchymal stem cell (BMSC)as the seed cell transplantation of tissue-engineered artificial nerve in the treatment of peripheral nerve injury. Methods BMSC was obtained from the bone marrow of adult rat through isolation and culture and combined with acellular nerve scaffold to construct ‘tissue-engineered artificial nerve’.After transplantation,rats were divided into two groups,the BMSC +acellular nerve conduit group(BMSC treatment group)and the empty cell conduit group(negative control group)with 5 rats in each group.Sciatic functional index (SFI)of the affected side of rats was compared between two groups at 2 weeks,4 weeks and 8 weeks after the surgery.Moreover,the sciatic conduction,recovery rate of tricipital muscle wet weight and other repair effects of the affected side were compared between two groups at 8 weeks after the surgery.Results The indicators of BMSC treatment group, including SFI assessed at 2 weeks,4 weeks and 8 weeks after the surgery as well as the sciatic conduction and recovery rate of tricipital muscle wet weight assessed at 8 weeks after the surgery,were better than those of the negative control group(all in P <0.05).Conclusions BMSC combined with tissue-engineered artificial nerve of acellular nerve scaffold can effectively promote nerve regeneration and function recovery.

Development of nerve scaffold in tissue engineering / 国际生物医学工程杂志

Peripheral nerve injury is very common in clinics. It has brought the patients with high rate of disability and huge economic burden and become one of serious health problems in the world. Nowadays, with the development of nerve tissue engineering, it provides new method for surgical procedures of nerve defects repair.The nerve scaffold plays a vital role in repairing nerve defects. It can provide temporary support for nerve cells to grow,adhere and to form structures. This review aims at introducing classification, properties and the applications of the nerve scaffolds for tissue engineering. Future development of the nerve scaffolds and remaining problems are discussed as well.

Evaluation of the biocompatibility of acellular nerve scaffold via three sterilization methods / 实用口腔医学杂志

Objective: To observe the biocompatibility of acellular nerve scaffold (ANS) via three sterilization methods, to provide experimental data for tissue engineering industrialization. Methods: Pig sciatic nerves were cut and treated using the NaOH maceration method. ANSs were sterilized by ethylene oxide, ~(60)Co-irradiation and peracetic acid. Evaluated the biocompatibility by MTT, cellular compatibility test, collagenase susceptibility test in vitro and local implantation test. Results: ANS retained the integrity of structure and major components of the basement membrane. The result of MTT test showed that the ANSs via different sterilization methods had statistical differences. There were no overall significant differences in Collagenase susceptibility test. Scanning electron microscope results showed the skin fibroblasts could attach, proliferate and grow well on the surface and holes of ANS with sterilization of PAA and Co~(60),a small quantity of cells adhered on ANS with sterilization of ETO. Tests for local effects after implantation show that different sterilization methods don't effect the ability of ANS to resist the enzyme degradation. In ETO group, rats showed an acute inflammatory response followed by chronic inflammation. In PAA and ~(60)Co group rats showed an acute inflammatory response that diminished such that the graft ultimately became indistinguishable from native tissue, observations that were consistent with graft acceptance. Conclusion: Peracetic acid sterilization offers a convenient alternative protocol for ANS processing. ANS sterilized with PAA shows good compatibility and biologic safety. It is an ideal sterilization method for ANS.

Efficacy of biomimicking chitosan scaffolds in bridging large nerve defect / 中国矫形外科杂志

[Objective] To develop biomimicking chitosan scaffolds with longitudinally oriented micro-channels,and investigate their efficacy in bridging 15 mm sciatic nerve gap in rats.[Methods]Chitosan scaffolds with longitudinally oriented micro-channels were fabricated using unidirectional freezing-dry methods.The chitosan scaffolds were used to bridge 15 mm nerve defect in rats,and their efficacy in bridging nerve gap was evaluated by morphometric analysis,retrograde labeling,electrophysiological studies and behavioral analysis.[Results]The chitosan scaffolds developed in the present study showed longitudinally oriented micro-channels,which resembled the dimensions of basal lamina channels in normal nerves.Implantation of chitosan scaffold achieved axonal regeneration and functional recovery similar to autograft implantation in vivo.[Conclusion]The chitosan scaffolds have inner microstructures which resemble the basal lamina channels in normal nerves.The chitosan scaffold may be used as an alternative to autograft in bridging nerve gaps.

Extraction of type I collagen and preparation of a collagen-gelatin scaffold / 中国矫形外科杂志

[Objective]To develop an ideal method for extracting type I collagen from cortical bone and to prepare a collagen-gelatin scaffold.[Method]The cortical bone was disintegrated into bone matrix powder in a high speed mill and was subsequently dehydrated in alcohol,decalcificated in hydrochloric acid and defatted in chloroform:methanol(1:1,v/v).The osscins were extracted using improved pepsin digestion method after the bone matrix powder was dissolved,centrifuged,dialyzed and lyophilized.Type I collagen was then characterized by SDS-PAGE and amino-acid composition analysis.The biomaterial was made of type I collagen and gelatin using freeze-drying method,and the alignment regularities of microscopic channels and their course directions were observed under the scanning electronic microscope.The size of the micropores and the factor of porosity were also measured.[Result] The collagen extracted was confirmed to be type I collagen by SDS-PAGE and amino-acid composition analysis.All the scaffolds looked like circular cylinder,the microscopic channels were arranged in parallel manners,and the pore sizes of the channels were uniform.[Conclusion]Ossein extracted from cortical bone is a real type I collagen that can be applied in the construction of collagen products.