| Neuropathic pain is defined as pain initiated or caused by a primary lesion or dysfunction in the nervous system' The spectrum of neuropathic pain includes a lot of disease, such as trauma, ischemic injury, infection/inflammation, cancer, drugs, compression and other unknown reasons. The mechanism of neuropathic pain is not understood now. IL - 6 is a proinflammatory cytokine. Increased IL - 6 in serum can induce increasing cyclooxygenase -2 ( COX -2). COX -2 evokes monocyte and macrophage synthesis massive PGE2 which can cause extensive and lasting vascular dilatation. All of these are very important in painful formation. There are seldom reports about relationships between changes of IL - 6 and monopathathic pain after sciatic nerve chronic constriction injury in rat. This report is in order to study the possibility of modified CCI model and the role of IL - 6 in monopathetic pain and monopathetic pain mechanism.Materials and Methods1. Material:(1) Radiant heat equipment: observing table was made of transparent glass which was 3mm thick and elevated on the cradle. The transparent plastic cage had five walls. Each wall had four holes (φ = 10mm) which were used in exchanging the air. Radiant heat was pro-vided by a 50W projector lamp. The beam (15mm) encompassed the glabrous skin including the toe pads. Withdrawal latencies were measured by a stopwatch as the time from onset of heating of the plantar surface of the hind paw to the time of withdrawal of the hind paw from the beam.(2) Animal model: All surgical procedures were performed under deep sodium pentobarbital anesthesia (45mg/kg, i. p. ). Opened the skin and isolated the sciatic nerve. Four 4-0 sutures were each tied loosely with a epidural tube with a square knot around the left sciatic nerve. Remove the epidural tube and check the gap between sutures and nerve. Keep the gap around 1mm. The right sciatic nerve was only mobilized. After sciatic nerve ligation, animals were maintained in clear plastic cages with solid floors covered with 3 ~ 6cm sawdust. Keep the airway smoothly. After the rat recover from anesthetic , all of them postoperatively displayed free feeding and drinking.(3 ) The standard of model success: ( a) gait and posture: left foot presented adduct and asthenia. The time of left paw on floor was significantly shorter than that right paw. (b) The ratio of withdrawal latencies of left and right paw ( PWL % ) less than 60% .2. Methods:(1) Animals: 36 healthy male Wistar rat weighing between 250 -300g were divided into three groups of 12 animals each. Rats were provided by China Medical University Second affiliated hospital department of animal experiment. Rats were feed in 12/12 hours of day/ night. Group A was control group. Group B was sham operation group. Group C was experimental group. Each rat of group C was measured by radiant heat equipment after operated day 3, 5, 7, 9, 11, 13, 15.(2) After day 15 operated, deep sodium pentobarbital anesthesia (45mg/kg, i. p. ) , animals were draw 5ml blood sample by heart, injected the blood sample to centrifuge tube. After standing 30min, the samples were centrifuged for lOmin and taking in superior liquid to Ependoff tube. After freezing in liquid nitrogen, keeping in -70t cryogenic refrigerator to the testing day. Group A is the serum of the health rats.( 3 ) Testing the IL - 6 level of each groups serum.4. Statistical and analysis:All data were expressed as means + SD. The data were analyzed with special statistical soft SPSS 10. 0. ANOVA and T test were applied to the data and statistical significance was considered at the 5% level.Results1. The baseline of thermal pain threshold was 18. 25 +2. 02s. Left and right paw thermal pain threshold had significantly different ( P<0.05).2. The post - operation PWL% of experimental group was significantly differently compared with pre - operation ( P < 0.05 ).3. IL - 6 level of serum in experimental group was significantly higher than that of sham group and control group ( P < 0.01).4. The ra...
|
PDF Full Text Request