Studies On The Innervation Of Cervical Intervertebral Discs And Its Clinical Significances In Rat Model

Objectives: 1.To study the innervation(distribution and number)and nerve categories(sensory nerve fibers,sympathetic and parasympathetic nerve fibers)of normal and degenerative cervical intervertebral discs in rats;2.To study the difference of mechanicoreceptors in normal and degenerative cervical intervertebral discs in rats;3.To study the roles of cervical intervertebral disc innervation on discogenic cervical pain,cervical vertigo and hypertension secondary to cervical spondylosis.Methods: Forty healthy SD rats,aged 3 months and weighted about 200 g,were divided into two groups(A and B groups),Group A is the degenerative experimental group and Group B is the healthy control group.In the experimental group,Percutaneous annulus fibrosus needle puncturing is used to induce the cervical discs degenerate.12 weeks later,the SD rats in the experimental group were taken X-ray and MRI.And after general anesthesia and perfusion,each rat's C2/3,C3/4,C4/5 and C5/6 discs were removal integrallty,and tissue slice was made to perform hematoxylin-eosin staining and immunohistochemical staining.Four specific antibodies CGRP?NPY?VIP and S-100 were used to mark sensory nerve fibers,sympathetic and parasympathetic nerve fibers and mechanicoreceptors.Then examining the expression of nerve fibers and mechanicoreceptors in the cervical intervertebral discs with microscope.We use spss 23.0 statistical software,P<0.05 was considered to be the level of significance.Results: There were sensory nerve fibers,sympathetic nerve fibers and parasympathetic nerve fibers in both experimental group and control group,and nerve fibers and mechanicoreceptors were obviously increased in the number and deeply ingrown into inner annulus fibrosus and even into nucleus pulposus in the degenerative cervical discs,the difference in two groups was significant(P<0.05).The number of nerve fibers and mechanicoreceptors were increased with the degree of degeneration.Conclusion: There were sensory nerve fibers,sympathetic and parasympathetic nerve fibers in rats' cervical intervertebral discs and they were obviously increased in the number and deeply ingrown into inner annulus fibrosus and even into nucleus pulposus in the degenerative cervical discs,and the number of nerve fibers and mechanicoreceptors were increased with the degree of cervical disc degeneration.