| Objective:To establishment the model of recurrent vertigo caused by labyrinthine fistula on guinea pigs, which will be used to research the mechanism of vestibular compensation of recurrent vertigo. Method: Selected thirty adult experimental guinea pigs, were randomly divided into A, B, C three groups.A was unilateral labyrinthectomy group, B was labyrinthine fistula manufactured and pneumatic otoscope used group, C was the pure labyrinthine fistula manufactured group.Three groups were operationed respectively, animals acted unilateral vestibular dysfunction symptoms after them awake(At this point for the time of postoperative zero), A and C as the control group without any treatment, the treatment of B group was increased the pressure inside the external auditory canal of the operational ear with pneumatic otoscope appropriately, once a day. Recording imbalance symptoms of these animals in different time after postoperative Oh,24h,48h, 1w,2w,3w respectively. Imbalances symptoms that is the frequency of spontaneous nystagmus, head deviation and unbalanced behavior scores. Result:Through quantitative observation to the animal spontaneous nystagmus、head deviation and unbalanced behavior scores, can show that the imbalance symptoms of group B had significant difference compared with other groups at the same period, except Oh. In the same group, nystagmus、head deviation and unbalanced behavior scores were the differences between the various time periods。Imbalances symptoms within each group gradually reduced over time until it disappeared, B was less than the other two groups on reduction degree. 48 hours after surgery, Three groups had no spontaneous nystagmus. B still appeared (5-6 times/15 seconds) nystagmus if using pneumatic otoscope appropriately increased the pressure inside the external auditory canal of the operation ear.The other two groups had no.2 weeks after surgery, The imbalance symptoms of A and C are not present. B still had head deviation and other imbalance symptoms. Also appeared (5-6 times/15 seconds) nystagmus if using pneumatic otoscope appropriately increased the pressure inside the external auditory canal of the operation ear. This phenomenon until existed three weeks after surgery. Conclusion:1.The method that manufacturing labyrinthine fistula and using pneumatic otoscope appropriately increased the pressure inside the external auditory canal of the operation ear, which can established vertigo animal model.2. Vertigo animal model established in this study can appear recurrent vertigo by inducing.Objective : Establishing the model of recurrent vertigo caused bylabyrinthine fistula on guinea pigs, with which to observe changes in expression of muscarinic receptors M2, M3 subtypes in medial vestibular nucleus of guinea pigs at different time points. Method: Eighty-eight adultexperimental guinea pigs were randomly divided into three groups, A was sham-operated group( n = 8), B was unilateral labyrinth lesion group( n = 40),C was labyrinthine fistula manufactured and pneumatic otoscope used group( n=40). After operation, guinea pigs of B、C were randomly selected eight according to different survival time(1 days,3 days, 1 weeks, 2 weeks, 3 weeks).All guinea pigs were perfused and the brain stem was taken,the expression of muscarinic receptors M2, M3 subtypes in MVN of guinea pigs were observed by immimohistochemistry, and were compared with those from sham-operated group. Result: Muscarinic receptor M2、M3 subtypes were induced decrease in both side MVN after operation inB、 C group. The expression in the 1 day after operation was least. The expression rising from the 3 day to 7 day after operation. No difference were observed between B group and sham operation group at 7 day after operation, While there was significant difference between C group and sham operation group at this time( p<0.05). Until 2 weeks after operation, no difference between C group and sham operation group. The expression of C group was weaker than that of B group at each period(Less than two weeks after operation). No difference had been observed in the ipsilateral and contralateral MVN at each group. Conclusion:1.There are M2、M3 muscarinic receptor subtype in MVN of guinea pigs, and the expression of M3 receptor may not be as abundant as M2 receptor, they may promote the normal process in the early stage of vestibular compensation. 2. In addition to the involvement of the cholinergic system, the vestibular compensation may also has the involvement of other neurotransmitters or chemical substances. 3.Further evidence of recurrent vertigo model caused by labyrinthine fistula was successful. |
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