The Effect of Intravenous Lipo-Prostaglandin E1 Injectioin in a Rat Foraminal Stenosis Model

Abstract

Background: Lipo–prostaglandin E1 (Lipo-PGE1) has vasodilating and platelet aggregation inhibitory characteristics and it has been used as a treatment for patients with blood flow dysfunction disease. Based on the mechanisms of lumbar spinal stenosis, including veno congestion, neuro-ischemia and mechanical compression, we aimed to study whether intravenous Lipo-PGE1 injection has any therapeutic effect on hyperalgesia in a rat foraminal stenosis model. Methods: In this study, twenty male Sprague-Dawley rats were divided into the control (n = 10) and Lipo-PGE1 (n = 10) groups. A small stainless steel rod was inserted into the L5�� 6 intervertebral foramen to induce intervertebral foramen stenosis and chronic DRG compression. In the Lipo-PGE1 group, 0.15μg/kg of Lipo-PGE1 were injected intravenously via a tail vein for 10 days startin g from the 3 rd day after operation. Behavioral testing for mechanical and thermal hyperalgesia was performed for 3 weeks after the injections. Results: From the 10 th day after Lipo-PGE1 injection, the rats in the experimental group showed significant recovery of their mechanical threshold, and this effect was maintained for 3 weeks. No significant differences of the thermal hyperalgesia were observed between the two groups. Conclusions: These findings suggest that intravenously injected Lipo-PGE1 may be effective for alleviating neuropathic pain, which isthe main symptom of spinal stenosis, by improving the blood flow dysfunction. (Korean J Pain 2007; 20: 15�� 20)