흰쥐 태생기 솔기핵과 사람탯줄혈액 이식 후 척수의 형태 재생에 관한 연구

Abstract

Many approaches have been adopted to restore function following spinal cord injury (SCI). These have included transplantation of fetal neurons, neuronal progenitor cells, or glial cells, or transplantation of transected cells which produce a variety of substances. The use of human umbilical cord blood (hUCB)―a rich source of nonembryonic or adult stem cells― has recently been reported to ameliorate behavioral consequences of stroke. The purpose of this study was to confirm the morphological restoration after transplantation of the human umbilical cord blood and fetal serotonin containing medullary raphe nuclei into the transected thoracic spinal cord(T9~T11) of adult rats. We performed that hUCB delivered intravenously in rats with compression injury of the spinal cord increase the rate of behavioral recovery. Twenty-four rats were divided into four groups: (1) SCI only(control); (2) SCI + hUCB delivered at one day post-injury ; (3)SCI + hUCB delivered at 3 days post-injury; (4) SCI + hUCB delivered at 5 days post-injury). SCI was produced by compressing the spinal cord for one minute with an aneurysm clip calibrated to a closing pressure of 50g. Spinal cords from these rats were examined immunohistochemically to identify hUCB. Spinal cords from SCI + hUCB animals contained hUCB in the area of SCI: No hUCB were found in non-injured areas of the spinal cord from these animals or in animals in which only a SCI was performed. Rats in the SCI + hUCB 1 day and 3 days group were significantly different in recovery of motor function as compared to the SCI + hUCB 5 days group. These results indicate that hUCB may be beneficial in reversing the behavioral effects of SCI. The suspension of cells derived from the mesencephalic and medually raphe nuclei of 13-15 day embryonic rats were injected in the upper and lower areas of the transected spinal cord(T9~T11). After survival periods of 15 days to 1 year, the animals were sacrificed and the spinal cord was processed for the localization of serotonin immunoreactive neurons in the transected spinal cord, and was studied using ABC immunohistochemistry. Immunohistochemical analyses revealed the presence of many serotonin immunoreactive neurons in the transplants. The serotonin nerve fibers were densely distributed in lamina I and II of the dorsal horn and in lamina VII and IX of the ventral horn of all segments of the spinal cord. The nontransplanted spinal cord of the control rats showed a total absence of serotonin immunoreactive fibers below the section. In the rats with simultaneous double hemisection(T8 and T12), hindlimb locomotion did not recover during the maximum observation period of 60 days, and in the rats with single hemisection in the thoracic cord(T8), hindlimb locomotion did recover during the maximum observation period of 30 days. In conclusion, we confirmed the morphological restoration of spinal cord after transplantation of the human umbilical blood and medullary raphe nuclei into the transected spinal cord as well as functional restoration, and we are sure that continuous stem cell study will give an oppotunity to treat the uncurable spinal disorders in the future.