Immunological rejection of acellular heterogeneous nerve transplant for bridging the sciatic nerve in rats

BACKGROUND：Artificial materials composed of acellular heterogeneous nerves can resolve donor shortage problems for the repair of peripheral nerve defects.However,it remains unclear whether artificial materials can overcome immunological rejection of heterogeneous nerve grafts and obtain similar effects as allogeneic nerve grafts.OBJECTIVE：To analyze regeneration and immunological rejection of defective sciatic nerves in rats through the use of acellular heterogeneous nerve grafts.DESIGN,TIME AND SETTING：A randomized,controlled study was performed at the Department of Anatomy,China Medical University and the Experimental Center,First Affiliated Hospital,China Medical University between January and December 2008.MATERIALS：TritonX-100 （Sigma,USA） and deoxycholate （Pierce,USA） were used.METHODS：Bilateral sciatic nerves were collected from adult rabbits and treated with TritonX-100 and sodium deoxycholate to prepare acellular sciatic nerves,which were used to bridge 1 -cm defective sciatic nerves in adult rats.MAIN OUTCOME MEASURES：The lymphocyte percentage in leukocytes was quantified following hemocyte staining.Neural regeneration and the recovery of motor end plates in the gastrocnemius muscle were observed under optical and electronic microscopy following toluidine blue staining,as well as acetylcholinesterase and succinate dehydrogenase histochemical staining.RESULTS：There was no significant difference in the lymphocyte percentage in leucocytes between transplanted and normal rats （P 〉 0.05）.At 3 months after surgery,the rat toes on the operated side were separated and the rats could walk.In addition,the footplates exhibited an escape response when acupunctured.A large number of regenerated nerve fibers were observed in the transplant group,and acetylcholinesterase-positive motor end plates were visible in fibers of the gastrocnemius muscle.CONCLUSION：Acellular heterogeneous nerve transplants for the repair of defective sciatic nerves in rats promote neural regeneration without significant immunological rejection.

Study of biological safety of scaffold material with heterologous deproteinized bone

To evaluate the biological safety of manufactured heterologous deproteinized bone and to provide an experimental basis for clinical applications. Methods ： Deproteinized bone （ 10 mm） and leaching liquor were made from pig ribs with a series of physical and chemical methods, then were evaluated through acute and subacute toxicity test, hemolysis test, pyrogen test, intracutaneous test, intramuscular implantation test and cytotoxity test. Results ： No obvious toxicity, hemolysis, pyrogenic characteristics, skin irritation, inflammatory reaction after intramusclar implantation and cytotoxity were observed. Conclusions： The heterologous deproteinized bone has good biological safety and meets all the demands of scaffold material for tissue engineering.