title: Methylprednisolone reduces the early vascular permeability increase in spinal nerve roots induced by epidural nucleus pulposus application.
abstract: Autologous nucleus pulposus is known to have injurious effects on spinal nerve roots when applied epidurally. Both inflammatory and immunological mechanisms have been implicated in this regard. Various proinflammatory substances might be released or activated by nucleus pulposus and might affect the endoneural nerve root vessels. The present study assessed nucleus pulposus-induced early vascular reactions and the possibility of blocking these reactions with intravenous, high-dose, methylprednisolone pretreatment. In 25 pigs, the S2 and S3 nerve roots were exposed. In five pigs (control group), retroperitoneal fat was applied epidurally on the nerve roots, and the other 20 pigs had nucleus pulposus applied. This group was sub-divided into the treatment group (n = 8), in which the pigs were pretreated with intravenous high-dose methylprednisolone (30 mg/kg body weight), and the nontreatment group (n = 12), in which the pigs received a corresponding volume of saline solution. After 2 hours, Evans blue labeled albumin was injected intravenously 5 minutes before death. Endoneural extravasation of Evans blue labeled albumin was evaluated with fluorescence microscopy. A marked albumin leakage was found in 67% of the nontreated animals, in 25% of those in the treatment group, and in none of the control animals. These results demonstrate that nucleus pulposus can induce a rapid increase in endoneural vascular permeability in spinal nerve roots after epidural application. This increase can be partially prevented by pretreatment with high-dose methylprednisolone.
authors.affiliation: Department of Orthopaedics, Göteborg University, Sahlgrenska University Hospital, Gothenburg, Sweden. Gunnar.Byrod@medfak.gu.se
authors.forename: G
authors.initials: G
authors.lastname: Byröd
authors.forename: K
authors.initials: K
authors.lastname: Otani
authors.forename: H
authors.initials: H
authors.lastname: Brisby
authors.forename: B
authors.initials: B
authors.lastname: Rydevik
authors.forename: K
authors.initials: K
authors.lastname: Olmarker
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology; D004487:Edema / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control; D007249:Inflammation / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control; D007268:Injections, Epidural / Q000009:adverse effects; D007403:Intervertebral Disc / Q000187:drug effects / Q000503:physiopathology / Q000637:transplantation*; D007405:Intervertebral Disc Displacement / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D017116:Low Back Pain / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D008775:Methylprednisolone / Q000494:pharmacology*; D011843:Radiculopathy / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D013126:Spinal Nerve Roots / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D013552:Swine; D016378:Tissue Transplantation / Q000009:adverse effects
chemical_list: D008775:Methylprednisolone