Objective To study the microstructural change of detrusor muscle and neuromuscular junction (NMJ) after bladder functional reconstruction for atonic bladder caused by medullary cone injury and to discuss the feasibility of bladder functional reconstruction for improving the detrusor muscle degeneration. Methods A total of 104 adult female Sprague-Dawley rats (weighing, 200-250 g) were randomized divided into 3 groups: normal group (n=8), control group (n=48), and experimental group (n=48). No treatment was given in normal group; the medullary cone injury was established by sharp transection of spinal cord at L4, 5 levels in control group; and the anastomosis of bilateral L5 ventral root (VR)-S2 VR and L5 dorsal root (DR)-S2 DR was performed for bladder functional reconstruction after modeling of medullary cone injury in experimental group. After operation, the survival condition of rats was observed. At 3 days and 3 consecutive days before 1, 2, 3, 4, 5, and 6 months after operation, the residual urine volume was measured; at 1, 2, 3, 4, 5, and 6 months after operation, the detrusor muscle was harvested to measure the muscle fiber cross-sectional area by HE staining, to calculate the percentage of connective tissue by Masson trichrome staining, and to observe the ultrastructure of the detrusor muscle and the NMJ by transmission electron microscope (TEM). Results Eleven rats were supplemented because of death after operation. In control group, a significant increase of the residual urine volume was observed with the extension of time (P lt; 0.05); in experimental group, an increase was observed at the first 3 months after operation, and then gradually decreased, showing significant differences between the other time point (P lt; 0.05) except between at 3 days and at 5 months after operation (P gt; 0.05); there was significant difference between control and experimental groups at other each time point (P lt; 0.05) except at 3 days, 1 month, and 2 months (P gt; 0.05). HE staining and Masson trichrome staining indicated that the muscle fibers arranged in disorder with gradually aggravated atrophy and gradually increased connective tissue in control group, while the shape of the detrusor muscle recovered with no increased connective tissue at 4, 5, and 6 months after operation in experimental group; there was significant difference in cross-sectional area of detrusor muscle and percentage of connective tissue between normal group and experimental group, and between normal group and control group at each time point (P lt; 0.05). In control group, the cross-sectional area of detrusor muscle decreased and the percentage of connective tissue increased with the extension of time (P lt; 0.05). In experimental group, the cross-sectional area of detrusor muscle decreased at the first 3 months and then increased, and the percentage of connective tissue increased slowly with the extension of time. There was no significant difference of cross-sectional area of detrusor muscle at the first 3 months between control and experimental groups (P gt; 0.05), but the values in experimental group were significantly higher than those in control group at 4, 5, and 6 months after operation (P lt; 0.05). There were significant differences of the percentage of connective tissue between control and experimental groups at each time point (P lt; 0.05). In control group, the amount of synaptic vesicles decreased in the NMJ with time passing; vacuole like structure was observed in NMJ at 3 months; there was almost no nerve ending at 6 months. In experimental group, the amount of synaptic vesicles decreased at 1 and 3 months after operation, but obviously increased at 6 months. Conclusion The reconstruction of bladder function with L5 nerve roots above the paraplegic plane can effectively inhibit the degeneration of detrusor muscle and improve its microstructural changes after medullary cone 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.
To introduce a micturition alert device dedicated to neurogenic bladders. Methods The design and mechanism of the micturition alert device were explained, the effectiveness was tested in a cranine experiment. Results The micturition alert device consisted of a permanent magnet sutured on the anterior bladder wall and a warning unit sutured on theinferior abdominal wall. The warning unit was assembled with a compass-l ike switch, a power supply, a buzzer and a power switch. Bladder volume determined the position of the magnet which determined the magnetic field at the point of the warning unit. The change of magnetic field was read by the warning unit. With increasing bladder volume from initial state to 200 mL in 8 dogs, the magnet moved cranially 32.8 mm averagely (from 31.3 mm to 34.1 mm) and the hand of warning unit turned 52° (from 47° to 57°). The value of the warning unit was correlated positively to the bladder volume (r =1.0, P lt; 0.01）. If the desired bladder volume was determined as 150 mL to activate the warning unit to alarm in advance, the fullness of bladder was 147.6 mL averagely from135 mL to 160 mL, with an error less than 15 mL (10%). Conclusion The micturition alert device including a warning unit and permanent magnet could monitor bladder volume continuously and alarm in time for the patients with loss of micturition desire. It is simple, easily-made, cheap and conveniently used. It is worth of further study.
Objective To study major influential factors of the micturition alert device dedicated to neurogenic bladders for the product design and cl inical appl ication of the device. Methods One ferrite permanent magnet with thickness and diameter of 3 mm and 10 mm, respectively, and three NdFeB permanent magnets with the thickness of 3 mm and diameter of 10, 15 and 20 mm, respectively, were used. The effects of thickness of the abdominal wall as well as the position and type of permanent magnets on the micturition alert device dedicated to neurogenic bladders were measured in vitro simulated test, when the abdominal wall was set to 2, 3, 4, 5, 6, 7, 8 and 9 cm, respectively, and the position of permanent magnets was 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 cm, respectively. The effect of the geomagnetic field on the device was measured under the condition that the thickness of the simulated abdominal wall was set to 2, 3, 4 and 5 cm, respectively,and the position of permanent magnets was 2, 3, 4, 5, 6, 7, 8, 9 and 10 cm, respectively. Results The value showed inthe warning unit was positively correlated with the position of the ferrite permanent magnet only when the thickness ofthe simulated abdominal wall was 2 cm (r=0.632, P lt; 0.05). The correlation between the value of the warning unit andthe position of NdFeB permanent magnets was significant (r gt; 0.622, P lt; 0.05), which was intensified with the increasingdiameter of NdFeB permanent magnets, but weakened with the increasing thickness of the simulated abdominal wall. The effect of the geomagnetic field was correlated with the exposition of the body, the position of the permanent magnet and the thickness of the abdominal wall. Conclusion The major influential factors of the micturition alert device dedicated to neurogenic bladder include the magnetism and location of the permanent magnet, the thickness of the abdominal wall and the geomagnetic field. These factors are correlated with and affect each other. Reasonable allocation of these factors may optimize the device.