A New Animal Model Of Trigeminal Neuralgia Produced By Administration Of Cobra Venom To The Infraobital Nerve In The Rat

[background] Trigeminal neuralgia is known as one of the greatest pain in human being, although many, but no one recognized ideal means, the difficulty to treat the disease is that the pathogenesis of trigeminal neuralgia is not clear. At present, the hypotheses such as the central of the pathogenic theory, around the pathogenic theory and vascular compression theory can not explain the clinical manifestations of TN. One of the obstacles of trigeminal neuralgia mechanism is the lack of an ideal animal model for trigeminal neuralgia, previous research on brain bolt under subarachnoid injection of penicillin G-K induced rat model of trigeminal neuralgia, chronic constriction injury of the rat infraorbital nerve model and the cat to pulp model has complex operation, specificity is not higher shortcomings, to establish a simple, easy and reliable animal model is necessary.[Objective] To establish a simple, easy, and reliable animal model of trigeminal neuralgia.[Methods]Experiment1:Forty Wistar rats were randomly divided into two groups, along the eyebrow upper margin arc incision, revealed in the medial orbital at the bottom of the infraorbital nerve, to the rat infraorbital nerve trunk injection of venom (concentration of0.1mg· L-1) or saline6u1. On the3day before surgery and after3,6,9,12,15,20,25,30,40,50,60,70,80and90days of mechanical threshold behavior determination. Observed the rat infraorbital nerve innervation area of pain threshold and pain reaction behavior of mechanical stimulation manifestations.Experiment2:Thirty Wistar rats, respectively, venom injection group was20and10in the control group only, along the eyebrow upper margin arc incision, revealed in the medial orbital at the bottom of the infraorbital nerve, to the rat infraorbital nerve trunk injection of venom (concentration of0.1mg· L-1) or saline6u1. We use video recording behavior of rats3days before surgery and3、7、14days。 We recorded the rats exploratory behavior, static behavior, grasping the face behavior, head shaking behavior, number and time licking hind behavior and lick the behavior of the body, we will be a camera is placed in front of the cage1meters.Experiment3:Four Wistar rats, venom injection group was2and2in the control group only. We produce venom trigeminal neuralgia model according to the method of experiment1. We cut the nerve tissue of rat medulla oblongata and infraorbital, and make electron microscopic section, to observe the medulla oblongata and infraorbital nerve tissue in the electron microscope。 Experiment4:Two Wistar rats, one side femoral vein infusion of5%Evans blue dye, when the rat body turn blue about a few minutes later, ION nerve sheath to inject venom or saline, observation of ION dominant regional vascular permeability to Evans blue leakage.Experiment5:We select the production has been completed venom model group16rats in experiment2. were randomly divided into treatment group and control group, with8rats in each group. Pregabalin treatment group take gastric lavage, drug dissolved in physiological saline solution, each perfusion30mg/kg, continuous infusion for6days,1daysbefore taking medicine and after taking medicine1,2,3,4,5,6,14days of ethology determination. We recorded the rats exploratory behavior, static behavior, grasping the face behavior, head shaking behavior, number and time licking hind behavior and lick the behavior of the body, we will be a camera is placed in front of the cage1meters.[results]1, Group of the experimental rats with mechanical pain threshold was significantly lower compared with the preoperative and group of the control。in infraorbital innervation area after three days(P<0.01)。 compared to rats with irritable, scratching the face or aggressive behavior. The pain threshold decreased mechanical continued to60days after operation, then gradually recovered, after90days to fully recover the preoperative. 2, The experimental group rats with exploratory behavior, static behavior, grasping the face behavior, shook his head behavior,compared with the preoperative and the control group had significant changes in the behavior after three days(P<0.01), behavior of Licking hind legs and licking body had no obvious change3day after surgery。 exploratory behavior, static behavior, grasping the face behavior, behavior change greatly shook his head, compared with the preoperative and the control group had significant changes in behavior. behavior of Licking hind legs and licking body had no obvious change and before operation and compared with the control group had no significant changes in the behavior of,7and14days after surgery。3,Group of venom modle, bulbar neurons appeared loose, myelin demyelination and axonal density, uneven distribution of change. Snake venom model group infraorbital nerve cells, demyelination changes of myelin loose solution.4, We inject venom in the rat infraorbital nerve sheath, after15minutes, the blue plaque around the nose lips. leakage of Evans blue significantly, while the control group almost no leakage of Evans blue.5, The experimental group rats with exploratory grasping the face behavior, shook his head behavior,compared with the preoperative and the control group had significant changes in the behavior, exploratory behavior, static behaviors, licking hind, licking behavior without significant change in body. Changes in the pregabalin group rats in second days feeding after grasping the face, head, static behavior, compared with the preoperative and the control group had significant changes in the behavior of exploratory behavior, licking hind, no significant change in body, licking behavior. Pregabalin group rats in third days feeding after grasping the face, head, change static behavior, exploratory behavior, compared with the preoperative and the control group had significant changes in the behavior, and no significant change of licking hind, licking behavior of the body. Pregabalin group rats in medicine,5,6, fourth and14days were grasping the face, head, static behavior, exploratory behavior, compared with the preoperative and the control group had significant changes in the behavior, and no significant change of licking hind legs, licking behavior of the body.[Conclusion] We injected the venom in the infraorbital nerve can cause allodynia in area supplied by the infraorbital nerve, spontaneous pain and related behavioral changes, medulla oblongata and infraorbital nerve demyelination changes, increased vascular permeability. This model gives the pregabalin Hello clothing, behavior changes of rats is inhibited, the above research results proved that the model can be used as animal model of trigeminal neuralgia.