The Study On The Effects Of Prefabricated Nerve On Motor Neurons In Spinal Cord Anterior Horn

Objective:In this experiment, using an autogenous vein to bridging tibial and peroneal nerve to prefabricate a nerve conduit through the establishment of New Zealand rabbit animal model, divided into blank group, epineurial window group, partial incision group to compare the changes of function and ultrastructure of motor neurons in spinal cord horn in the different stages of use different methods to prefabricated nerve.Methods:1. Thirty clean grade adult male and female New Zealand rabbit were randomly divided into three groups, ten in blank group, ten in epineurial window group, ten in partial incision group. The experimental group according to the sampling time after operation, respectively, after3days,7days,28days, divided into three subgroups.2. All surgical procedures were carried out under anesthesia. An epineural window on the tibial and peroneal nerves was opened1cm above the fibulae capitulum. Then using10-0suture end-to-side anastomosis bridging vein, cut off part of the nerve bundle of donor nerve trunk and implanted venous lumen in partial incision group. The blank group only exposed the tibial and peroneal nerves.3. At3,7,28days after operation specimen was obtained from the spinal cord(L4-L6) under deeply general anesthesia. The change of number and morphology of motor neurons were observed on HE-stained sections; the function of spinal cord change was detected in BDNF and NGF; the ultrastructural change of spinal cord anterior horn motor neurons was observed with transmission electronic microscope.Results:1. The epineurial window group animals act normal in the all limbs except local red and swelling, with the innervation recovering, limb swelling reduced. In partial incision group animals displayed unilateral lower limb slight paralysis postoperatively, and slight ulcer of the plantar could be saw in five animals.2. The HE-stained showed:the blank group and epineurial window group didn’t change significantly and the partial incision group had a slight change.3. Imrnunohistochemistry and immunofluorescence detection showed:in partial incision group, the expression of BNDF began to increase in3days, and continued to increase in7days, and increased gradually in1month, the expression of NGF didn’t increased significantly until1month. The expression of BDNF and NGF didn’t increased in the other two groups. 4. Observation of transmission electronic microscope:in epineurial window group vacuoles appeared in the cytoplasm in3days, nuclear membrane disappeared and lysosomes appeared in7days, the nucleus appeared again and mitochondrial recovered in1month. In partial incision group the nucleolus and nuclear membrane was intact, but the cytoplasmic organelles vacuole was appeared in3days, that meant cell edema. Apoptosis began and ultrastructure changed significantly in7days. The damaged neurons began to recovery in1month.Conclusions:1. After prefabricated nerve caused peripheral nerve injury, the spinal cord motor neurons degeneration, although the number of neurons decreased but changed slightly. The damaged neurons begun to recovery after four weeks.2. If the nerve only prefabricated by open the epineurial window, whether from the morphology, or from the function did not cause obvious effect to the motor neurons in spinal cord horn.3. If the nerve prefabricated by partially incised nerve through the epineural windows and fascicular injury was performed, although from the morphology caused no obvious change, but the function will cause a certain degree of effects.