Activation Of Microglia Effects The SNI Neuropathic Pain In Rat

In the present study,the author established the rat spared nerve injury(SNI)model,and different dosage interfere factor adminstered,then to observe the behavioral outcomes by means of behavioral parameter testing, immunofluorescence to investigate the effect of intraperitoneal minocycline on rat spared nerve injury neuronthic pain model.Methods1.Animal model of the spared nerve injuryAccording to the manner of Decosterd and Woolf,after anesthesia the skin on the lateral surface of the thigh was inscide and a section made directly through the biceps femoris muscle exposing the sciatic nerve and its three terminal branches:the sural,common peroneal and tibial nerves.The SNI procedure comprised an axotomy and ligation of the tibial and common peroneal nerves leaving the sural nerve intact.2.The method of mechanical withdrawal threshold(MWT) testingAccording to Kingery's methods using Von Frey hair to operate.3.The method of thermal withdrawal duration(TWD)testing.According to Hargreaves's methods using BME-410 Full-automatic plantar analgesia tester to operate.4.Immunofluorescence method:To exame the expression of OX-42 in spinal cord5.Experimental paradigm:Sixty Four SD rats were randomized into four group:(1)the control group(Sh).(2)the Spared nerve injury model group(SNI). (3) minocyline40mg/kg group(Mb).(4) minocyline 10mg/kg groupe(Ms),Minocyline(40,10mg/kg intraperitoneally)was administered twice a day systemically,beginning 1day prior to nerve transection and lasting 3 days.Observation index includes:the MWT and TWD were assessed before surgey 1 day and after surgey 1st,3rd,7th,14th day;The changes of different groupes spinal microglia response to spared nerve injury at the 1st,3rd,7th,14th day were detected by immunofluorescence with OX-42.Results1.The SNI model groupe appeared that MWL was decreased and TWL was prolonged significantly.There was statistical difference between Sh and S NIgroupe at either time.2.The degree of decreased MWT and prolonged TWL in both Mb and Ms groupes has statistical difference compared to SNI groupe,and the same difference between Mb and Ms groupe.3..Minocyline administration resulted in a dose-dependent reduction of the expression of OX-42.Conclusion1.There was significant mechanical hyperalgesia and thermal hyperalgesia after spared nerve injury..2.The activation of central microglia had the cooperative effects on the development of the neuropathic pain of the rat's SNI model.3.Minocyline intraperitoneal administration resulted in a dose-dependent reduction of the expression of OX-42;Inhibition the activation of microglia can alleviate mechanical hyperalgesia and thermal hyperalgesia It also suggests that activated microglia participate in the formation which was neuropathic pain after spared nerve injury.