| ObjectiveTo investigate the effect of Sacral Nerve Root Stimulation on the preventing and treating of the gut origin bacterial translocation and endotoxemia in rabbits with acute complete spinal cord injury. To declare the pathophysiological mechanism of bacterial translocation and endotoximia indued by constipation after paralysis and illustrate the principles of SNS. To provide a basis for a theory and a new method for clinic.Methods1,According to Fehlings'method, we used the aneurysm clip and transected the spinal cord. We monitored the the Somatosensory evoked potentials and Motor evoked potentials (before SCI and 10,30,90 and 120 mins after SCI) to verify the degree of transsection. We recorded the bioelectricity at different sites of gastrointestinal tract, the pression in the colon, and the rectal anal reflex fore and after SCI in some rabbits (n=6). Then we observed the symptoms in abdomen﹑the defecation and the changes in the intestine function by paunch at 24 h after SCI in the other rabbits (n=6).2,The stimulator was putted around the S3. We began the stimulation from the low intensity to high till the tail and leg got shiver (got the threshold). On the basis, we stimulated in three intensity (6,8 and 10V), the frequence of 15 Hz, and the pulse of 400μs;Secondly we fixated the intensity of 6V, stimulated in pulse of (200,400 and 600μs).We analyzed the recordings and found the parameters which adapt to the rabbits mostly.3,The rabbits were randomly divided into nomal control group (NCG, n=6), control group (CG, n=18) and experimental group(EG, n=18).The latter two groups were divided into subgroups of 24, 48 and 72 h after SCI. There were six rabbits in each subgroup. The EG were the rabbits of paraplegia that were stimulated in sacral 3 nerve root. The CG were the rabbits of paraplegia without stimulation, and the normal CG were normal rabbits. The stimulation parameters were identical for all rabbits: pulse width, 400μs; frequency, 15 Hz; amplitude was adaptable to the rabbits (limited range, 6-10 V).The stimulation period was 2 hours, with 10 minutes stimulation and 10 minutes rest intermittently, two times per day at 8:00-10:00 am and 6:00-8:00 pm. The samples were collected at 24, 48, and 72 h after spinal cord injury.Under aseptic manipulation,samples of blood,liver,spleen and mesenteric lymph node were collected for bacterial cultures and endotoxin detection.The small intestine were observed by light microscope and electron microscope.Results1,Retention of urine appeared immediately after the spinal cord was transected on T6 level. Abdominal distension and constipation was aggravating with the time extending. We paunched the abdomens and found intestinal tympanites obviously, transmission of light of intestinal wall strengthened, and intestinal peristalsis was slow down. A lot of stool was accumulated in the cecum, colon, and rectum. The intestinal peristalsis of the colon was weakened. The bioelectricity at different sites of gastrointestinal tract and the pression in the colon were weakened obviously especially in single haustrated colon and diatal colon. The rectal anal reflex nearly disappeared after SCI and compatibility of anorectal canal changed. This model was the right one which to study the bacterial transloction and endotoximia induced by constipation after SCI.2,We found SNS rehabilitated the peristalsis of denervated colon and the compatibility of anorectal canal by the stimulation parameters of our trial,which promoted defeacation. Poststimulus voiding of the urine happened immediately after the SNS. But the stool defecation need more time and higher stimulated intensity.3,Bacterial translocation and endotoxemia happened after spinal cord injury, which complicated paraplegia in both the control group and the experimental group . Sacral 3 nerve root stimulation improved the defecation (F=19.974, P=0.000) in rabbits of paraplegia and remarkably reduced the endotoxin (F=16.786, P=0.000) content in the blood to normal level and the incidence rate (n=18, P<0.01) of the gut origin bacterial translocation. However, those of the control group aggravated with the time following. The pathological changes got more and more remarkable with the constipation and endotoxemia aggravating in control group. However, the change was not obvious in experiment group.Conclusions1,Abdominal distension and constipation aggravating can appear after the spinal cord was transected on T6 level. The intestinal peristalsis disability in single haustrated colon and distal colon, the rectal anal reflex nearly disappeared after SCI, the injuried structure of mucous membrane, and bacteria overgrowth resulted of the accumulated stool are the physiopathologic mechanism of bacteria transloction and endotoxemia.2,SNS can rehabilitate the peristalsis of denervated colon and the compatibility of anorectal canal to promote defeacation. Poststimulus voiding of urine happen easier and earlier than stool defecation. The stimulation parameters that got from our experiment are adapt to the rabbits: pulse width, 400μs; frequency, 15 Hz; amplitude was adaptable to the rabbits (limited range, 6-10 V). The stimulation period was 2 hours, with 10 minutes stimulation and 10 minutes rest intermittently, two times per day at 8:00-10:00 am 6:00-8:00 pm.3,After spinal cord injury happened, SNS can improve intestinal tract motion and defecation in rabbits of paraplegia and reduce the incidence rate of the gut origin bacterial translocation and the endotoxemia, which is beneficial to reduce the occurrence of systemic inflammatory response syndrome (SIRS) , multiple organ dysfunction syndrome (MODS), and the danger of infection after surgery.
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