ABSTRACT
STUDY DESIGN: Determination of functional and biochemical parameters as well as the effect of specific therapies on these parameters, in the experimental model of neurotrauma in rabbits. OBJECTIVE: To assess the effect of indomethacin (0.1-3.0 mg/kg for 9 days), a potent inhibitor of endogenous prostaglandin synthesis, on the motor activity and on the spinal cord tissue concentration of free palmitic, stearic, oleic, arachidonic and docosahexaenoic acids in an experimental model of a spinal cord injury in rabbits. SETTING: Faculty of Medicine, University of Rijeka, Croatia. METHODS: The animals were randomly divided into nine experimental groups, four sham and/or vehicle-treated and five indomethacin-treated (including one sham-operated and four injured groups). Laminectomy was followed by contusion of the spinal cord, using a modification of the technique of Albin. Motor activity was controlled daily during the course of the next nine postoperation days and scored using Tarlov's system. Spinal cord samples from the impact injury site were taken and frozen in liquid nitrogen. Total lipids were isolated and purified by a modification of the method of Folch. Free fatty acids (FFAs) were separated from the total lipid extract by preparative thin-layer chromatography, converted to the corresponding methyl esters and identified using gas chromatography, using nonadecanoic acid as the internal standard. RESULTS: The concentrations of all analysed free fatty acids were increased in the spinal cord after neurotrauma, in comparison to control tissues. Treatment of injured rabbits with indomethacin resulted in a significant decrease in spinal cord FFAs and exerted a positive effect on neurotrauma-induced motor impairment. CONCLUSION: These results indicate a mechanism whereby indomethacin protects rabbits from the sequellae of neuronal damage caused by trauma, and suggests that it may be beneficial in the therapy of neurotrauma. SPONSORSHIP: This work was supported by the Croatian Ministry of Science and Technology (project 062019).
Subject(s)
Fatty Acids, Nonesterified/metabolism , Indomethacin/therapeutic use , Motor Activity/drug effects , Paraplegia/prevention & control , Paraplegia/physiopathology , Spinal Cord Injuries/drug therapy , Spinal Cord Injuries/physiopathology , Spinal Cord/metabolism , Animals , Disease Models, Animal , Paraplegia/etiology , Rabbits , Spinal Cord/drug effects , Spinal Cord Injuries/complications , Treatment OutcomeABSTRACT
Significant plastic changes in spinal nociceptive processing appear to accompany peripheral nerve injury or inflammation. Using a well-established model of neuropathic pain, we have recently reported that loose ligation of the sciatic nerve was accompanied by a long-lasting post-tetanic potentiation of sciatic-evoked A-fiber superficial dorsal horn field potentials. In the present study we demonstrate that the typical disappearance of thermal hyperalgesia as a behavioral sign of neuropathic pain several weeks after loose sciatic nerve ligation is accompanied by the loss of the long-lasting potentiation. These data suggest that a significant but reversible shift in the processing of sensory information in the spinal dorsal horn follows peripheral nerve injury, and lend further support to the notion that long-lasting synaptic plasticity may contribute to the development of neuropathic pain.
Subject(s)
Nerve Fibers, Myelinated/physiology , Neuralgia/physiopathology , Posterior Horn Cells/physiology , Sciatic Nerve/physiopathology , Animals , Chronic Disease , Electric Stimulation , Hot Temperature , Hyperalgesia/physiopathology , Ligation , Long-Term Potentiation/physiology , Male , Neuronal Plasticity/physiology , Nociceptors/physiology , Pain Threshold/physiology , Posterior Horn Cells/ultrastructure , Rats , Rats, Sprague-DawleyABSTRACT
The aim of this study was to test the hypothesis that the use of an operating microscope improves the results of peripheral nerve repair. Tibial nerve grafting was carried out on 48 Fischer rats divided into 2 groups: in one, a loupe was used, and in the other a surgical microscope. At 5 months after grafting, recovery was evaluated by functional, electromyographic, and morphometric tests. The mean motor nerve conduction velocity was 26.77 +/- 9.37 m/sec in the group where the loupe was used compared with 44.19 +/- 11.36 m/s when the microscope group was used. The soleus muscle weight and the diameter of myelinated fibres also confirmed better regeneration in the microscope group. These results clearly indicate that it is essential to use the microscope for peripheral nerve repair.
