Elevated VEGF in Degenerative Intervertebral Discs in Rats with Injured Intervertebral Discs of the Caudal Vertebrae

Abstract

Introduction Recently, inflammatory cytokines, which are elevated in degenerative intervertebral discs, have been recognized as targets of drug therapy for discogenic back pain. Some reports have shown that the level of vascular endothelial growth factor (VEGF), a protein involved in angiogenesis, is elevated at inflamed sites, and we believed that VEGF could be a target for the treatment of discogenic back pain. Thus, we investigated the presence of VEGF in degenerative intervertebral discs in rats with injured intervertebral discs of the caudal vertebrae. Materials and Methods Forty male rats (age, 8 weeks) were divided into two groups: injured group (intervertebral discs between the fifth and sixth, and sixth and seventh caudal vertebrae were punctured 10 times using a 26G needle) and noninjured group (intact discs). The intervertebral discs were collected at 1, 4, 7, and 14 days after the procedure ( n = 5 from each group at each time point), and quantitative evaluation of VEGF was performed using ELISA. Results The VEGF level was maximum 1 day after the procedure, and then the level gradually decreased. In addition, the VEGF levels during the entire study period were significantly higher in the injured group compared with those in the noninjured group ( p < 0.05). Conclusion In this study, injury to the intervertebral discs resulted in elevated VEGF levels. This finding confirms the increased production of inflammatory cytokines in injured intervertebral discs and indicates that VEGF might be involved in discogenic back pain. Moreover, the presence of elevated VEGF levels during the study period shows that VEGF might be responsible for lingering pain. Anti-VEGF antibodies are already in use in the ophthalmic field. On the basis of the findings in this study, a clinical trial involving the administration of anti-VEGF antibodies into the intervertebral discs for the treatment of low back pain in humans was approved by the review committee in September 2013 and will be performed in the near future. Disclosure of Interest None declared