Objective To investigate the feasibil ity of establ ishment of physiological micturition reflex arc by simultaneously reconstructing the sensory and the motorial nerve of atonic bladder after spinal cord injury. Methods Eight 1-year-old Beegle male canine were selected, weighing 7-12 kg. The left side was the experimental side, while the right side wasthe control side. Epidural microanastomosis of vertebral canal of the left L7 ventral root to S2 ventral root and L7 dorsal root to S2 dorsal root was performed to reconstruct the sensory and the motorial function of atomic bladder. The right side was used as a control without treatment. The new motor-to-motor, and sensory-to-sensory physiological bladder reflex pathway were establ ished after 12 months of axonal regeneration. Then S1-4 segmental spinal cord was destroyed for preparation of complete paraplegia. The electrophysiological examination and the bladder pressure were detected before and after paraplegia. The canine micturition was observed for 3 months after paraplegia. Nurohistological observation was performed after canine sacrifice. Results Of 8 canine, 7 canine survived. After paraplegia, canines displayed urinary incontinence and frequent micturition at first, nocturnal continence was achieved gradually without frequent micturition after 1 month. Urinary infection at different degrees occurred in 3 canines and was controlled after Norfloxacin was administered orally. The bladder pressure increased to (1.00 ± 0.13) kPa, (0.90 ± 0.12) kPa after trains of stimulation (300 mV, 0.3 ms, 20 Hz, 5 seconds) of S2 dorsal root at the experimental side before and after paraplegia respectively, showing no significant difference (P gt; 0.05). It increased to (1.90 ± 0.10) kPa after the same train of stimulation of S2 dorsal root at control side. There was significant difference between the experimental side and the control side (P lt; 0.01). Single stimulation (300 mV, 0.3 ms) of the S2 dorsal root at the experimental side resulted in evoked potentials recorded from the left S2 ventral root before and after paraplegia. Before and after paraplegia, the ampl itudes of the evoked potentials were (0.68 ± 0.11) mV and (0.60 ± 0.08) mV respectively, showing no significant difference (P gt; 0.05). It was (1.21 ± 0.13) mV while stimulating at the control side. There was significant difference between the experimental side and the control side (P lt; 0.01). Neurofibra of L7 dorsal and ventral root grew into S2 dorsal and ventral root on tissue sl ice under l ight microscope. Conclusion Reconstruction of the bladder physiological micturition reflex arc is feasible by anastomosis of sacral dorsal and ventral root below injured spinal plane with the suprasacral survival dorsal and ventral root above the plane respectively for restoration of atonic bladder after spinal cord injury.
To establ ish the animal model of the artificial physiological reflex arc with the reconstruction of the sensory and the motorial functions of atonic bladder simultaneously in the rats, and to provide the foundation to furtherinvestigate the repairing effectiveness of this technique. Methods There were 20 adult male SD rats (weighing 280-300 g)which were randomly divided into 2 groups (n=10): group A and group B. Group A was anastomosis of the ventral roots(VR) and the dorsal roots (DR) between L6 and S2 simultaneously to establ ish the model of the artificial physiological reflex arc. Group B was anastomosis of the main trunk between L6 and S2 to establ ish the model. The contents of the observation included: ① To measure the external diameter of the VR, DR and the main trunk of L6 and S2 with the sl iding cal iper; and to measure not only the distance between L6 and S2 but also the separable length of L6 with the ruler. ② Fast Blue dyeing of the VR, DR and the main trunk of L6 and S2 was performed to count their nerve fibers assisted by the Leica FW4000 system 2 weeks after opertation. ③ The observation of the urination of the rat and BBB scoring to evaluate the motorial function of the lower l imbs was performed postoperatively. Results ① L6 located in the lateral side of the S1-4 in the vertebral body of L6. The external diameters of the VR, DR and the main trunk of L6 were (0.68 ± 0.13), (0.88 ± 0.10) and (1.54 ± 0.33) mm, respectively, while those of S2 were (0.62 ± 0.08), (0.79 ± 0.14) and (1.39 ± 0.42) mm, respectively. The distance between L6 and S2 was (14.21 ± 1.95) mm, and the separable length of L6 was (10.76 ± 2.11) mm. Furthermore, the microdissection indicated the VR and the DR between L6 and S2 could be anastomosed respectively with no-tension at the level of the vertebral body of L6; and the main trunk of L6 and S2 could be anastomosed with no-tension at the level of the confluens of L5, 6. ② With Fast Blue dyeing, there were 892 ± 32, 354 ± 26 and 532 ± 17 nerve fibers of the VR, DR and the main trunk of L6, respectively. And there were 788 ± 29, 325 ± 19, and 478 ± 22 nerve fibers of the VR, DR and the main trunk of S2, respectively. There were no volar ulcer,trichomadesis and self-eating of the affected l imbs in the both groups postoperatively. The urinations of the rats after operationwere not different from those before operation. The mean BBB scores of pre- and postoperation in group A were 20.20 ± 0.35 and 19.80 ± 0.23, respectively; the mean BBB scores of pre- and postoperation in group B were 20.20 ± 0.35 and 19.20 ± 0.31, respectively. There was no significant difference of the above indexes between group A and group B (P gt; 0.05). Conclusion Anastomosis of the VR and the DR between L6 and S2 simultaneously in rats is an ideal animal model to establ ish the artificial physiological reflex arc owing to its simple and reproducible procedures.
Objective To investigate the rule of the morphological changes of the detrusor muscle and its neuromuscular junction after the medullary cone injury in rats. Methods Forty-eight SDadult rats were divided into 6 groups randomly, each of which was 8. There werenormal control group(group A), 4 weeks group(group B), 6 weeks group(group C), 8 weeks group(group D), 10 weeks group(group E) and 12 weeks group(group F) after the medullary cone injury respectively. The medullary cone injury was completed in the level of L4,5 with a sharp and transsectional way. The HE dyeing of the detrusor muscle was performed firstly to observe the changes of the section areas of muscle fibers. And the electron microscopic samples of the detrusor muscle were made to investigate the rules of the ultrastructructral changes in the detrusor muscle and its neuromuscular junction. Finally, the Masson trichromatic dyeing of the detrusor muscles was performed to calculate the percentages of the smooth muscle and the connective tissue.Results The HE dyeing of the detrusor muscle indicated the section areas of muscle fibers in groups E, F was significantly less than that in group A (P＜0.05). The gradually aggravated ultrastructructral changes of detrusor cells in groups B-F were observed in atonic bladders，such as various shape and size，malalignment, wide separation between musclecells, abundant collagen fibrils and irregular dense structures between individual cells, obvious rough endoplasmic reticulum widen and mitochondrial edema were noted．And the ultrastructructral changes of the neuromuscular junctions manifested that the similar structures in group A and the reduction of the mitochondria and synaptic vesicles was seen in groups B, C and D, the conspicuous degenerative neuromuscular junction and the obvious reduction of the synaptic vesiclesand the mitochondria was observed in group E,and the deteriorative degenerativeneuromuscular junction and the obvious reduction or disappearance of the synaptic vesicles and the mitochondria even to the degenerative corpuscle was noted in group F. The Masson trichromatic dyeing in the detrusor muscles indicated that there were significant differences in the percentage of the connective tissue in the detrusor muscles between groups E,F and group A, and between group E and group F respectively (P＜0.05). Conclusion The irreversible changes of the detrusor muscle and its neuromuscular junction canbe seen in the 10th week after medullary cone injury in rat. And the nerverepairing procedures should be performed before this.
Objective To study the advance in the treatment of atonic bladder after spinal cord injury. Methods The rencent literature concerned was extensively reviewed and some methods of therapy for atonic bladder were introduced. Results No effective method of therapy was found for atonic bladder after spinal cord injury. When compared with clean intermittent catheterization, pharmacologic therapy, compressive micturition and detrusor function reconstruction, the establishment of an artificial bladder reflex arc may have a potential of controllable micturition. Conclusion To establish an artificial bladder reflex may provide an update of current therapeutic concepts for atonic bladder after spinalcord injury.