Effect of the artificial somato-autonomic neuroanastomosis on defecation after spinal cord injury and its underlying mechanisms

Abstract

A new artificial somatic-autonomic neuroanastomosis has been established in male rats with spinal cord injury (SCI). Anorectal manometry and neural retrograde tracing were conducted in this animal model to analyze the mechanisms and the effects on recovery of anorectal function. The left L4 ventral root (L4VR) was intradurally micro-anastomosed to the L6 ventral root (L6VR) to establish the new regenerated neural pathway. Three months later the spinal cord was completely transected at the T9–10 level. Eight weeks later the model rats were randomly divided into two groups. The rats in the group 1 (n=8) were applied for anorectal manometry, and those in the group 2 (n=4) were used for neural retrograde tracing study with fluorogold (FG) and dextran tetramethylrhodamine (TMR). The results of anorectal manometry showed the new reflex pathway could induce rectum to contract and simultaneously electric activity of external anal sphincter (EAS) to become weak or disappearing (indicating synergetic relaxation of EAS). FG and TMR dual labeled neurons with round and elliptical shape were mainly observed in L4 angulus anterior of model rats. The regenerated neural pathways were effective to improve the rectum external sphincter synergetic status and restore the anorectal function.

Keywords

somato-autonomic neuroanastomosis / spinal cord injury / synergetic defecation

References

[1] KroghK., NielsenJ., DjurhuusJ.C., et al.. Colorectal function in patients with spinal cord lesions. Dis Colon Rectum, 1997, 40(2): 1233-1239

[2] VogelL.C., KrajciK.A., AndersonC.J.. Adults with pediatric-onset spinal cord injury: part 1: prevalence of medical complications. J Spinal Cord Med, 2002, 25(2): 106-116

[3] LiuC.W., HuangC.C., ChuanC.G., et al.. Relationship between neurogenic bowel dysfunction and health-related quality of life in persons with spinal cord injury. J Rehabil Med, 2009, 41(1): 35-40

[4] KayabaH., HebiguchiT., ItohY., et al.. Evaluation of anorectal function in patients with tethered cord syndrome: saline enema test and fecoflowmetry. J Neurosurg Spine, 2003, 98(3): 251-257

[5] BeneventoB.T., SipskiM.L.. Neurogenic bladder, neurogenic bowel, and sexual dysfunction in people with spinal cord injury. Phys Ther, 2002, 82(2): 601-612

[6] XiaoC.G., GodecC.J.. A possible new reflex pathway for micturition after spinal cord injury. Paraplegia, 1994, 32(3): 300-307

[7] XiaoC.G., GodecC.J.. Mechanism underlying the skin-CNS-bladder reflex pathway. Proceedings of the 1995 annual scientific meeting of the international medical society of Paraplegia, New Delhi, India, 1995, 11: 2-4

[8] XiaoC.G., de GroatW.C., GodecC.J., et al.. Skin-CNS-bladder reflex pathway for micturition after spinal cord injury and its underlying mechanisms. J Urol, 1999, 163(9): 936-942

[9] XiaoC.G., DuM.X., DaiC., et al.. An artificial somatic-central nervous system-autonomic reflex pathway for controllable micturition after spinal cord injury: preliminary results in 15 patients. J Urol, 2003, 170(4Pt1): 1237-1241

[10] XiaoC.G., DuM.X., LiB., et al.. An artificial somatic-autonomic reflex pathway procedure for bladder control in children with spina bifida. J Urol, 2005, 173(6): 2112-2116

[11] XiaoC.G.. Rennervation for neurogenic bladder: historic review and introduction of a somatic-autonomic reflex pathway procedure for patients with spinal cord injury or spina bifida. Eur Urol, 2006, 49(1): 22-28

[12] KaraS., IstekD., OkandanM.. Low-cost instrumentation for the diagnosis of hirschsprung’s disease. J Med Syst, 2000, 27(2): 157-162

[13] FillmannH.S., LlessuyS., MarroniC.A., et al.. Diabetes mellitus and anal sphincter pressures: an experimental model in rats. Dis Colon Rectum, 2007, 50(4): 517-522

[14] BradingA.F., RamalingamT.. Mechanisms controlling normal defecation and the potential effects of spinal cord injury. Prog Brain Res, 2006, 152(8): 335-343

[15] GonellaJ., BouvierM., BlanquetF.. Extrinsic nervous control of motility of small and large intestined and related sphicters. Physiol Rev, 1987, 67(2): 902-961

[16] GuytonA.C., HallJ.E.. . Textbook of Medical Physiology, 200010th edUSA, W.B. Saunders Co.216-342

[17] LynchA.C., FrizelleF.A.. Colorectal motility and defecation after spinal cord injury in humans. Prog Brain Res, 2006, 152(5): 335-343

[18] VizzardM.A., BrissonM., De GroatW.C.. Transneuronal labeling of neurons in the adult rat central nervous system following inoculation of pseudorabies virus into the colon. Cell Tissue Res, 2000, 299(4): 9-26

[19] MaggiC.A., GiulianiS., SanticioliP., et al.. Neural pathways and pharmacological modulation of defecation reflex in rats. Gen Pharmacol, 1988, 19(9): 517-523

[20] DitunnoJ.F., LittleJ.W., TesslerA., et al.. Spinal shock revisited: a four-phase model. Spinal Cord, 2004, 42(4): 383-395

[21] AndersonK.D.. Targeting recovery: priorities of the spinal cord injured population. J Neurotrauma, 2004, 21(7): 1371-1383

[22] NoutY.S., SchmidtM.H., TovarC.A., et al.. Telemetric monitoring of corpus spongiosum penis pressures in conscious rats for assessment of micturition and sexual function following spinal cord contusion injury. J Neurotrauma, 2005, 22(4): 429-444

[23] HolmesG.M., Van MeterM.J., BeattieM.S., et al.. Serotonergic fiber sprouting to external anal sphincter motoneurons after spinal cord contusion. Exp Neurol, 2005, 193(1): 29-42

[24] LiuZ., LiuC.J., HuJ.W., et al.. An electrophysiological study on the artificial somato-autonomic pathway for inducing voiding. Nail Med J China, 2005, 85(5): 1315-1318