Zhang Y, Kerns JM, Anderson DG, Lee YS, Chen E-Y, Tannoury C, An HS: Sensory neurons and fibers from multiple spinal cord levels innervate the rabbit lumbar disc. Am J Phys Med Rehabil 2006;85:865–871.
To establish the neurotransmission pathway from the lumbar L5/6 intervertebral disc (IVD) to the spinal cord in the rabbit.
Fluorogold particles injected into the posterior portion of the rabbit L5/6 IVD were traced by examining gold-positive neurons and fibers in the dorsal root ganglion (DRG) and spinal cord at various root levels.
Fluorogold-labeled neurons were observed bilaterally in primary afferent DRG neurons from the L3 through L5 segments; a small number of gold-labeled neurons were found at the L1 level. Fluorogold-labeled neurons were predominantly present in the ipsilateral DRG (the side of the injection) at the L5 level, but they were more equally distributed (on both sides) at the L4 and L3 levels. In the posterior horn of the spinal cord, Fluorogold particles were found in nerve fibers as rostral as the T12 level.
Our study has shown that Fluorogold particles injected into the rabbit L5/6 IVD are taken up by primary sensory neurons in the DRGs and primary sensory fibers in the posterior horn of the spinal cord at multiple levels. This diffuse innervation pattern of the lumbar disc may help explain why discogenic back pain in humans is often poorly localized.
From the Departments of Orthopedic Surgery (YZ, YSL, HSA), Neurological Sciences (JK, E-YC), and Anatomy (JK), Rush University Medical Center, Chicago, Illinois; and the Departments of Rehabilitation Medicine (YZ), Dermatology (YZ), and Orthopedic Surgery (GA, CT), Thomas Jefferson University, Philadelphia, Pennsylvania.
Dr. Yejia Zhang was supported by the NICHHD (2K12 HD0197-7) through the Rehabilitation Medicine Scientist Training Program (RMSTP). This work was supported, in part, by a grant provided by Rush University Medical Center.
All correspondence and requests for reprints should be addressed to Dr. Yejia Zhang, Thomas Jefferson Iniversity, Department of Rehabilitation Medicine, 233 S. 10th Street Room #430, Bluemle Life Sciences Building, Philadelphia, PA 19107.