The Effect of MK801 and Morphine on the Expression of GAP-43 and NGF in the Dorsal Root Ganglion during the Development of Neuropathic Pain
|Keywords||Growth associated protein-43 Nerve Growth Factor Neuropathic pain MK801 Morphine|
Purposes neurobehavioral experiments combined with immunohistochemistry study the effects of MK801 and morphine on the outer peripheral nerve injury neuropathic pain model in rats neurological behavior change and growth associated protein 43 (growth associated dorsal root ganglion protein, GAP-43) and nerve growth factor (nerve growth factor, NGF) expression. 85 methods and materials adult SD rats, male or female, were randomly divided into five major groups, group I: normal control group (5 rats), group II: sciatic nerve chronic constriction injury (chronic constriction injury, CCI) group, Group III: saline treated control group (CCI NS group) after sciatic nerve chronic constriction injury IV Group: sciatic nerve chronic constriction injury the the MK801 treatment groups (CCI MK801 group), V group: sciatic nerve chronic constriction injury morphine treatment group (CCI Morphine group), II, III, IV and V group press postoperative sampling time divided into 1, 3, 7, 14 days four subgroups (5) in each subgroup. The surgery only damage to the right side of the sciatic nerve, the left as normal controls. MK801 dose of 0.1mg/kg q12h intraperitoneal injection the morphine administered a dose of 5 mg / kg q12h intraperitoneal injection. II, III, IV and Group V rats at 1, 3, 7, 14 days after the flinching reflex threshold (MWT) measurement in rats machinery and heat shrink leg latency (TWL), after the measurements taken with the injured side dorsal root ganglia, dorsal root ganglia, sciatic nerve connected to the method of application of immunohistochemistry and image analysis of GAP-43 and the expression of NGF and semi-quantitative analysis. Results MWT and TWL: ① Compared with normal group, CCI group, CCI NS Group, CCI MK801 group and CCI Morphine group rats one day after MWT and TWL difference had no statistical significance (P gt; 0.05); ② Compared with the normal group, CCI group, CCI NS group CCI MK801 group and CCI Morphine group rats 3, 7, and 14 days after MWT and TWL was significantly shorter (P lt; 0.01); ③ CCI group and the CCI NS group compared to the same point in time MWT and TWL difference without statistical significance (P gt; 0.05); ④ CCI MK801 group compared with the CCI NS group, 3, 7, and 14 days after the same time point MWT and TWL were significantly prolonged ( P lt; 0.01); the ⑤ CCI Morphine group compared with the CCI NS group, 3, 7, and 14 days after the MWT and TWL same time point (P lt; 0.01) dorsal root ganglion GAP-43 and NGF were significantly prolonged expression: ① Compared with normal group, CCI group, CCI NS group, CCI MK801 group and CCI Morphine group postsurgical GAP-43 and NGF expression was significantly increased (P lt; 0.01); ② The CCI group and the CCI NS group, GAP-43 and NGF expression difference was not statistically significance (P gt; 0.05); ③ CCI MK801 group CCI NS group, postoperative time points dorsal root ganglion GAP-43 and NGF expression significantly reduced (P lt; 0.01); ④ CCI Morphine group CCI NS group comparison, postoperative time points dorsal root ganglion GAP-43 and NGF of expression were significantly reduce (P lt; 0.01); ⑤ CCI group GAP-43 expression of gradually increasing trend during the observation period, peak to 14 Telsda; CCI group expression of NGF in the first significant increase after 3 days, and then gradually decreased, but remained at higher expression status, and preoperative p lt; 0.01. Conclusion 1. GAP-43 and NGF and neurogenic pain occurred close relationship. Sciatic nerve chronic constriction injury model of neuropathic pain, dorsal root ganglion GAP-43 and NGF expression than the normal group increased significantly, suggesting that GAP-43 and NGF may be involved in the formation of the molecular mechanisms of neuropathic pain. MK801 intraperitoneal injection of MK801 0.1mg/kg q12h produce significant analgesic effect on neuropathic pain in rats, significantly inhibited the increase in dorsal root ganglion GAP43 and NGF expression, indicating that the inhibition of the expression of GAP43 and NGF is peripheral town one of the mechanisms of pain. However, did not make the GAP-43 and NGF to normal, combined with behavioral experiments failed to meet the dose of MK801 completely inhibited the effect of treatment of neuropathic pain. Intraperitoneal injection of morphine 5mg/kg q12h on neuropathic pain in rats can produce significant analgesic effect, significantly inhibited the increase in dorsal root ganglion GAP43 and expression of NGF, that inhibit the expression of GAP43 and NGF peripheral analgesic morphine One of the mechanisms. However, did not make the GAP-43 and NGF to normal, combined with behavioral experiments failed to meet the dose of morphine completely inhibited the effect of treatment of neuropathic pain.