Efficacy of Anti-NaV1.7 Antibody on the Sensory Nervous System in a Rat Model of Lumbar Intervertebral Disc Injury

PURPOSE: The pathophysiology of discogenic low back pain is not fully understood. Tetrodotoxin-sensitive voltage-gated sodium (NaV) channels are associated with primary sensory nerve transmission, and the NaV1.7 channel has emerged as an analgesic target. Previously, we found increased NaV1.7 expression in dorsal root ganglion (DRG) neurons innervating injured discs. This study aimed to examine the effect of blocking NaV1.7 on sensory nerves after disc injury. MATERIALS AND METHODS: Rat DRG neurons innervating the L5/6 disc were labeled with Fluoro-Gold (FG) neurotracer. Twenty-four rats underwent intervertebral disc puncture (puncture group) and 12 rats underwent sham surgery (non-puncture group). The injury group was divided into a saline infusion group (puncture+saline group) and a NaV1.7 inhibition group, injected with anti-NaV1.7 antibody (puncture+anti-NaV1.7 group); n=12 per group. Seven and 14 days post-surgery, L1 to L6 DRGs were harvested and immunostained for calcitonin gene-related peptide (CGRP) (an inflammatory pain marker), and the proportion of CGRP-immunoreactive (IR) DRG neurons of all FG-positive neurons was evaluated. RESULTS: The ratio of CGRP-IR DRG neurons to total FG-labeled neurons in the puncture+saline group significantly increased at 7 and 14 days, compared with the non-puncture group, respectively (p<0.05). Application of anti-NaV1.7 into the disc significantly decreased the ratio of CGRP-IR DRG neurons to total FG-labeled neurons after disc puncture at 7 and 14 days (40% and 37%, respectively; p<0.05). CONCLUSION: NaV1.7 antibody suppressed CGRP expression in disc DRG neurons. Anti-NaV1.7 antibody is a potential therapeutic target for pain control in patients with lumbar disc degeneration.

Biologic Response of Degenerative Living Human Nucleus Pulposus Cells to Treatment with Cytokines

PURPOSE: To investigate the molecular responses of various genes and proteins related to disc degeneration upon treatment with cytokines that affect disc-cell proliferation and phenotype in living human intervertebral discs (IVDs). Responsiveness to these cytokines according to the degree of disc degeneration was also evaluated. MATERIALS AND METHODS: The disc specimens were classified into two groups: group 1 (6 patients) showed mild degeneration of IVDs and group 2 (6 patients) exhibited severe degeneration of IVDs. Gene expression was analyzed after treatment with four cytokines: recombinant human bone morphogenic protein (rhBMP-2), transforming growth factor-beta (TGF-beta), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). Molecular responses were assessed after exposure of cells from the IVD specimens to these cytokines via real-time polymerase chain reaction and immunofluorescence staining. RESULTS: mRNA gene expression was significantly greater for aggrecan, type I collagen, type II collagen, alkaline phosphatase, osteocalcin, and Sox9 in group 1 than mRNA gene expression in group 2, when the samples were not treated with cytokines. Analysis of mRNA levels for these molecules after morphogen treatment revealed significant increases in both groups, which were much higher in group 1 than in group 2. The average number of IVD cells that were immunofluorescence stained positive for alkaline phosphatase increased after treatment with rhBMP-2 and TGF-beta in group 1. CONCLUSION: The biologic responsiveness to treatment of rhBMP-2, TGF-beta, TNF-alpha, and IL-1beta in the degenerative living human IVD can be different according to the degree of degeneration of the IVD.

experimental study of the effects of nicotine on the intervertebral disc

Clinically it had been noticed that a large proportion of patients presenting with low back pain are smokers. Therefore, in this experimental study the histological effects of nicotine on the lumbar intervertebral discs of the rabbits was investigated. Eighteen rabbits were divided equally into 3 groups, Group I [a and b]; as control. Group 2 injected intraperitoneally by 5000 ng/kg nicotine daily for 4 weeks. Group 3 injected intraperitoneally by 5000 ng/kg nicotine daily for 8 weeks. The selected dose produced blood nicotine levels equivalent to those found in heavy smokers [30 cigarettes / day]. Light and electron microscopic studies revealed that nicotine injection showed a variety of histological changes, which were not observed in the control group. This includes appearance of spaces within the nucleus pulposus and separation from the adjacent fibrous lamellae in the annulus fibrosus. Also loss of the regularity of the multilayered structure of the annulus fibrosus, and excessive inclusions associated with vacuoles which continue with the rough endoplasmic reticulum within the chondrocytes. Disc degeneration was more marked in rabbits injected with nicotine for 8 weeks [G3] than in those injected for 4 weeks [G2]. It could be concluded that the disc degeneration is more common among smokers and is correlated with the duration of exposure to nicotine

Disc susceptibility of lomefloxacin: a new difluroquinolone

In vitro antibacterial activity Lomefloxacin, a new quinolone derivative, was tested, and the activity was also compared with other antibacterials including other quinolone derivative. No particular advantage of Lomefloxacin over other drugs was found