The Experimental Study On The Application Of Neural Stem Cell In Reimplantation Of Avulsed Ventral Root Into Spinal Cord Brachial Plexus Injury

ObjectiveTo investigate the survival effect and mechanisms of Neural Stem Cells on motoneurons after being transplanted into the spinal cord and observe the survival and differentiation of Neural Stem Cells in the spinal cord after brachial plexus roots avulsion.MethodsSixty adult SD rats were randomly devided into the experimental group and the control-group,with 30 each.The ventral and dorsal roots of C5～C6 were both avulsed from the spinal cord outside the dura mater and within the vertebral canal. The ventral root of C6 was reimplanted into the ventral horn under microscope.The dorsal root was left unattended.The ventral and dorsal roots of C5 were placed inside the nearby muscles.The Neural Stem Cells were injected into the spinal cord nearby the ventral horn with a microinjector in the experimental group.For the control group,the D—Hank solution was also injected the site.At 2,4,6,8,12,24 weeks postoperatively,the C6 spinal cord was stained with HE and immunohistochemistry assay.The change of number and morphology of motoneurons were observed on HE-stained sections;The Neural Stem Cells were identified using immunohistochemistry assay and the lost motoneurons were counted on Tunel-stained sections.Result:1.57 rats were alive and 3 rats were dead.All animals displayed unilateral upper limb paralysis postoperatively and other limbs were not affected.2.At each time point postoperatively,the HE-stained transverse sections showed: The number of motoneurons decreased significantly with soma atrophied.At 24 weeks postoperatively,the number of lost motonertons of control rats and experimental rats reached 84.3%and 63.7%,respectively.The survival rate of motoneurons of experimental rats is higher than control rats at all time points. 3.Immunohistochemistry assay showed BrdU positive cells scattered in the operational side of the spinal cord of experimental rats at 24 weeks postoperatively,and these cells still maintained nondifferentiated character.4.Tunel-stained transverse sections revealed that positive apoptotic motoneurons scattered in the ventral horn of the control group were lower than the experimental group.Conclusion:1.After brachial plexus roots avulsion,degeneration of motoneurons will take place in the ventral horn of the spinal cord.2.The mechanisms for motor neuron delayed degeneration in adult spinal cord following brachial plexus root avulsion is apoptosis.3.The Neural Stem Cells can survive and protect motorneurons of the ventral horn from delayed degeneration after reimplantation of brachial plexus roots avulsion.