The Study Of Preparation Of Acellular Spinal Cord Scaffold And Its Safety Evaluation In Vivo

Objective The purpose of this study is to use the chemical extraction method to remove the cells completely,and maintaining structural integrity of the extracellular matrix at the same time,so as to keep the natural three-dimensional structure.It was made into acellular spinal cord scaffold in the last.The prepared acellular spinal cord scaffolds was made into suspension.The acellular spinal cord scaffold suspension was injected into rats through tail vein to evaluate its safety in rats.Method 1.At first,we take out 4 rats,and the spinal cord of the rats was made into acellular spinal cord scaffold by chemical extraction.HE staining and myelin staining were used to observe the surface structure of the acellular spinal cord.2.Acellular spinal cord scaffold were prepared by grinding into 500 ml normal saline,made into acellular spinal cord scaffold suspension.48 Wistar rats were divided into 2 groups,one group as the experimental group,another group as control group,each group were divided into 6 time nodes,corresponding to 1 days,2 days,3 days,7 days,10 days,14 days.In the experimental group,2ml of the acellular spinal cord scaffold suspension was injected into rats through tail vein,and in control group,we used saline instead of the acellular spinal cord scaffold suspension.After intravenous injection for 1 days,2 days,3 days,7 days,10 days,14 days,the rats were killed after blood was taken.The levels of alanine aminotransferase(ALT)and creatinine(CREA)were measured and analyzed statistically.In the last,the rats were killed and the lung,liver,spleen,heart and kidney were made into tissue sections for HE staining to observe the histological changes.Result 1.The acellular spinal cord scaffold was white,cylindrical,and the diameter and length were slightly shorter,the texture was soft,the toughness was increased,and there was no peculiar smell.HE staining and myelin staining showed that the mesh structure cross the section of spinal cord scaffold showing different size,the cells were completely removed,there were no blue nuclei and red cytoplasm,axon and myelin sheath were removed and the cell walls composed by extracellular matrix were stained pink.2.After the acellular spinal cord scaffold suspension was injected into rats through tail vein,there were obvious inflammatory reaction and hyperplasia in the experimental group.The liver cells were swollen,unable to distinguish the cell boundaries,the nuclei were loose.This phenomenon was more severe in the first day after tail vein injection,and then gradually recovered,and the liver morphology returned to normal state until the tenth day.By measuring the blood alanine aminotransferase(ALT)content,we found that ALT content remained at a high level in the first two days,then gradually decreased to normal value.There was no significant change in renal pathological examination,and serum creatinine(CREA)was not significantly different from the control group.Spleen pathology showed that the area of lymph nodules gradually increased,the marginal area was not clear,and there were a large number of lymphocytes in the red pulp,and returned to normal form in the fourteenth day.No significant changes were observed in cardiac pathology.Conclusion 1.The acellular spinal cord scaffold prepared by chemical extraction method can keep the integrity of the extracellular matrix as far as possible,and maintain its natural spatial structure.2.The acellular spinal cord scaffolds suspension were injected into rats,and the body has a toxic reaction.It is harmful to the morphology and function of the liver.There is some damage to lung tissue structure.In the spleen,the humoral immunity is mainly caused by B cells.There is no damage to the morphology of cardiac cells.There is no damage to renal cell morphology and renal function.Compared with the traditional biomaterial scaffold,acellular spinal cord scaffold has better biocompatibility,mechanical strength and morphology.It provides a basis for the treatment of spinal cord injury with acellular spinal cord scaffold in the future.