Study of the combined effect of granulocyte-colony stimulating factor with methylprednisolone in the treatment of acute spinal cord injury in rats

Abstract

In recent decades, several studies were conducted in an attempt to obtain a more effective treatment for the spinal cord injury. All these studies involve basically four types of approach to the patient with an acute spinal cord injury: surgical, biological and pharmacological and physical therapy. Among the methods of pharmacological treatment, corticosteroids are approved for use in humans. Randomized, double blinded, prospective clinical trials, have shown that methylprednisolone is clinically effective. In addition to it´s anti-inflammatory effect, it also increases the blood flow, stabilizes the cellular membrane, and inhibits the lipid peroxidation which results in a reduction of free radicals formation.The granulocyte-colony stimulating factor (G-CSF) is a glycoprotein that is most known due to it´s role as a growth stimulating factor for hematopoietic progenitor cells. Studies have demonstrated that G-CSF also have other non-hematopoietic functions and may increase the tissue regeneration of several organs as brain, heart, and the spinal cord. In the acute phase of spinal cord injury, it mobilizes cells derived from the bone marrow to the area of spinal cord, inhibits neuronal and oligodendrocytes apoptosis, protects the myelin and inhibits the expression of inflammatory citokynes as TNF-alpha and IL-1 beta. In the subacute phase, it stimulates the angiogesis after the spinal cord injury.This study have the objective to evaluate, in an experimental standardized model of rats submmited to an acute spinal cord injury, the combined effect of the G-CSF and methylprednisolone on the result of functional, neurophysiological and anatomopathological improvement.Forty wistar rats will be randomly assigned to four groups with then animals each:· Control group - rats with moderate spinal cord injury through a computerized equipment for spinal cord impact by dropping weight - NYU Impactor® ("New York University Spinal Cord Contusion System - Impactor"), of a height of 25 mm; G-CSF group - rats submitted a moderate spinal cord injury with the NYU Impactor, and treated with G-CSF at the moment of the spinal cord injury and daily for five days; G-CSF/Metylprednisolone group - rats submitted a moderate spinal cord injury with the NYU Impactor, and treated with G-CSF at the moment of the spinal cord injury and daily for five days and methylprednisolone for 24 hours; Metylprednisolone group - rats submitted a moderate spinal cord injury with the NYU Impactor, and treated with methylprednisolone for 24 hoursAnimals will be kept alive for 35 days. The functional evaluation will be done with BBB scale on days 2, 7, 14, 21, 28, 35. The neurophysiological evaluation will be done with somatosensitive evoked potentials on the 35th day. The histological evaluation will be done on the spinal cord injury zone after euthanasia on the 35th day. (AU)