Effect Of Cervical Intervertebral Disc In The Pathogenesis Of The Cervical Vertigo

Objective: 1.To get the massage of the innervation(distributi- on and growth-into depth)and nerve category(sympathetic nerve fibers and sensory nerve fibers)in the normal Rat cervical inter- vertebral disc. 2.To study the blood perfusion on the blood supply(opisthion-by the external occipital protuberance)of Vertebrobasilar artery while variation of pressure in the cervical intervertebral disc. 3.To investigate the role of cervical interver- tebral disc(Nervous Factors and stimulus of pressure in interver- tebral disc)in cervical vertigo.Methods: Forty grown Wistar rats ,weight(250g³50g). 1.Immunohistochemistric study was performed to observe the innervation and nerve category in cervical intervertebral disc. To observe the distribution of nerve fibers by microscope. 2.We monitorred the result of blood perfusion on the blood supply (opisthion-by the external occipital protuberance)of Vertebro- basilar artery while variation of pressure in the cervical interver- tebral disc with laser-Doppler flowmetry(LDF). The experiment was divided into two parts:experiment 1 and experiment 2.Experiment 1: The C_5/6 and C_6/7 cervical intervertebral discs of 8 Wistar rats from 40 ones of which were selectived on random for the experiment were stripped as laboratory specimens. The specimens which as cervical intervertebral disc unit(inclued cervical intervertebral disc and its cartilage endplate)were fixed, decalcified, paraffin-embedded, and then consecutivelly paraffin sectioned at 5μm for Hematoxylin- Eosin(H-E) stain. The sympathetic nerve fibers and sensory nerve fibers in two slices which the intervertebral disc section seemed integrated by the HE stain were examined using immunohistochemistry with NPY and SP(nerve transmitter) antibody while two slices used as Negative Control. Immuno- histochemistric study was performed in Autologous jejunal Organization which was used as positive control.Experiment 2: Sixteen Wistar rats were selectively on random from forty rats, then they were divided into two groups:C_5/6 stimulation group and C_6/7 stimulation group. The blood perfusion on the blood supply(opisthion-by the external occipital protuberance)of Vertebrobasilar artery was observed using laser-Doppler flowmetry(LDF) before and after the pressure stimulation applying to the intervertebral disc.Results:1 Experiment one1.1 Hematoxylin-Eosin(HE) stain: The shape of cervical intervertebral disc through light microscope seems like suborbicular or elliptic with its slight protuberant advancing edge and concave after skirt. The intervertebral disc include nucleus pulposus and anulus fibrosus. The nucleus pulposus looked like soft gelatinoid and located in the center of the disc while the anulus fibrosus looked like lamellar and embraced the nucleus pulposus. Annulus fibrosus neatly arranged with different shape between dvancing edge and concave after skirt. The front part of the Annulus fibrosus is the thickest in the line, with both sides of the disc gradually become thinning. The ahead of the annulus fibrosus seems like crescentiform while the bake consists of a thin collagenous fibre.1.2 Control experiment: All the results of the negative control experiment are negative; the results of the positive control experiment show that the small intestinal wall is rich in positive matters for SP and NPY immunoreactive nerve fibers.1.3 Immunohistochemistry: Immunohistochemical SP is good at particularity and the background is not colored or a light yellow. Positive SP-immunoreactive nerve fibers and NPY- immunoreactive nerve fibers were located in the front edge and back edge of C_5/6 and C_6/7 cervical intervertebral discs. Sixty-three percents(5/8) and fifty percents(4/8) showed immunoreactivity for NPY in the front edge and back edge of C_5/6; Seventy-five percents(6/8) and fifty percents(4/8) showed immunoreactivity for SP in the front edge and back edge of C_5/6; Fifty percents(4/8) and sixty-three percents(5/8) showed immunoreactivity for NPY in the front edge and back edge of C_6/7; Sixty-three percents(5/8) and seventy-five percents(6/8) showed immunoreactivity for SP in the front edge and back edge of C_6/7. Positive expression rate compared with the negative control group was statistically significant(P<0.05). The positive of nerve distribution in front edge and back edge was not statistically significant(P>0.05). Immunoreactive fibers that located in the outer 1/3 of the annulus fibrosus near the edges were colored ranging from light-brown to dark brown which looked like point linear or enlargement of granular matters.2 Experiment twoThe results of blood perfusion on the blood supply(opisthion- by the external occipital protuberance)of Vertebrobasilar artery which were before and after the pressure stimulation applying to the intervertebral disc were not statistically significant(P>0.05).Conclusions: The distribution of sympathetic nerve fibers and sensory nerve fibers in the cervical intervertebral disc may be the physiological fundament which received the stimulus from the intervertebral disc pathological changes, and they maybe played an important role in Cervical vertigo. Peptidergic nerves of the two irritations may be related to a series of symptoms of sympathetic nerve stimulation. The pressure in degenerated intervertebral disc is a pathologic stimuli which can lead to disc herniation. In addition, this pressure may make sympathetic high excited. However, this study showed that the pressure stimulation in normal cervical intervertebral disc will make no difference to the blood flow of vertebrobasilar artery which was dominated by sympathetic nerve. The pressure stimulation in normal cervical intervertebral disc may not lead to the incidence of vertigo.