Vascularization Of The Muscle Basal Lamina Transplanted Into The Rat Semi-transected Spinal Cord

It has been showed that the histological characteristic of transected spinal cord is progressive hemorrhagic necrotizing in the gray matter from the cutting end to distal part. Glial scar is the main obstacle for axonal regeneration in the transected spinal cord after the necrosis of cutting end. As a result, a supporting structure for axon regeneration is prerequisite to replace the glial scar area and to provide a regenerative environment for endogenic nerve fiber in injured spinal cord. The studies have proved that the injured spinal cord has the capability of regeneration. It has also been showed that the transplantation of the scafford into the spinal cord has protective effect on the neurons with transected axon. This require a rich blood supply to the graft after the transplantation. The network of blood vessels in the interior and outerior of graft is propitious to the migration of the seed cells and the sustainance of their activity. It also provide enough nourishment for the growth of regenerating axons, which provide a good material foundation for the axons'growth. For the repair of injured spinal cord, the revascularization of the graft is a focus of the current research works. This thesis is try to figure out the circumstances of the revascularization of muscle basal lamina transplanted into semi-transected spinal cord. In this study, the rat spinal cord is semi-transected to manufacture the rat spinal cord injury model. Muscle basal lamina is produced by frozen-thawed process. Enzyme histochemical techniques and stereological techniques are also conducted to evaluate the vascularization of the muscle basal lamina in 3,5,7,14 and 28 days after transplantation.Part 1 The manufacture of the muscle basal laminaThe muscle basal lamina has a good biocompatibility which can promote the adherent and proliferation of the cell. Also it has low immunogenicity and its degradation products are avirulent. In addition it can be made into different shape according to the requirement. The basal lamina itself represents a component of the extracellular matrix to which regenerating axons attach preferentially, and the basal lamina tubes provide spaces for the regenerating axons to grow through. Thus, basal lamina tubes, as in acellular muscles, represent favorable scaffolds for regenerating axons.1. gross observationBy gross observation, the muscle basal lamina present rosiness, which is opaque and rigid. There is little change in shape after frozen-thawed process.2.histologic structureIn longitudinal section of the muscle basal lamina with HE stains , the compoment of the muscle cell are still present. But their integrity is damaged. There are space between and parallel to muscle cells.Part 2 revascularization of muscle basal lamina transplanted into the rat semi-transected spinal cordThe revascularization is the basis of tissue regeneration. The scaffold materials for tissue engineering must have characteristic to guaranteed that the seed cells in the scaffold can get sufficient nutrition in time. So the reconstruction of the blood supply is the key point for the transition from basic research to the clinic application.1.the rat spinal cord modelThe 30 Wistar male rats(300-400g) were divided into 5 group with 6 in each group.After anesthetization the skin and muscles overlying the midthoracic cord at T10–T11 were separated and retracted, and then after laminectomy, the underlying spinal cord segment was exposed. Using both blades of the scissors, the spinal cord was semi-transected . The 5 mm block of the spinal cord tissue between the two cuts was completely removed, leaving the two stumps of spinal cord exposed. Then the scaffold was put into the gap. Then the would is closed. After the operations, the rats were sacrificed in 3,5,7,14 and 28 days.2. General status changesAll animials wake up in 2-4 hours. In the day of operation, the both hind limbs were paralyzed and can not support the body. Two weeks after operation the hind limbs can slightly moved. All rats survive and have no emiction difficulty.3. Enzyme histochemical techniques observation1) 3 days after operations, only a few blood vessels is present in the junctional area between the spinal cord and muscle basal lamina. There is no blood vessels in the scafford. The junction between the scafford and spinal cord is loose. It is easy to seperate the scafford from the spinal cord . 2) In the fifth day after the operation, the number of blood vessels were increased.In some area of the junction the blood vessels were densely distributed.But new blood vessels were arranged in a disorderly pattern.3) In the 7th,some blood vessels are present in the interior of the scafford. The scafford is connected firmly to the spinal cord.4) 14 days later, the blood vessels were densely distributed in some area of the scafford. Some area form a network of blood vessels5) 28 days later, the blood vessels growed into the deep area of the scafford. Some blood vessels go through the whole scafford. And blood vessels were mainly arranged parallel to the direction of the long axis of the scafford.In addition, it has been proved that the degradation of the scafford will affect the formation of blood vessels in the scafford. In our study, the muscle basal lamina is not degraded, and the scafford has good a good biocompatibility with the spinal cord.This study shows that the muscle basal lamina can be well vascularize after the transplantation in the rat semi-transected spinal cord. The muscle basal lamina can establish a good fusion with the spinal cord .