An Experimental Study On The Model Of Internal Ear Ischemia Induced By Thrombus Method And Its Correlative Factor

The relative stabilization of the internal ear microcycle is maintains its normal physiological function, but each kind of pathogenic factor causes internal ear's ischemia will change the abnormality to destroy this state of equilibrium, will cause the pathology physiology change, will produce the corresponding function barrier.This experiment discusses establishes one kind of chronic internal ear ischemia animal model and research the correlative factor.1 ObjectiveHow discusses to establish the animal model of the chronic internal ear ischemia, by most approaches in the pathology physiological process in human, provides the corresponding basic research method for the clinical related internal ear microcycle barrier diseases;And through the research of electricity physiology's change in ischemia period, hoped to help to this kind of disease early diagnosis, the monitor as well as the prognosis appraisal;And through researching the change of organization in reactive oxygen species content in ischemia period, we can further clear about the cochlea ischemia damage the mechanism.2 Methods2.1 Before the neck, center the margin, nearby before the trachea the passive separation guinea pig, organizes to the skull bottom, the electric drill to move the occiput skull bottom, observes the guinea pig cerebellum, before carefully under the anterior inferior cerebellar (AICA) with the basilar artery (BA) the relations, seek for and identify AICA correctly, experiments the solution function forms in the blood vessel thrombus with 40% or 50% trichloride ferric.2.2 Divides stochastically the guinea pig into 3 groups: Normal group, surgery group, thrombus group. The surgery chooses the ventralis admission passage, nearby before the trachea the passive separation guinea pig, organizes to the skull bottom, exposes the occiput skull bottom, the electric drill moves the skull bottom ossein to expose AICA, use the 40%FeCl3 filter paper to paste spreads outside the blood vessel, the function forms in the blood vessel the thrombus. In the technique monitors the cochlea blood flow(CoBF) to change, the experiment fore-and-aft surveying experimental animal listens to the auditory brainstem response (ABR), the thrombus group guinea pig takes the AICA make frozen section, the hematoxylin-erosin (HE) dyeing observe the thrombus shape. After the technique, the breeding animals surpass 7 days, achieves the goal of making chronic model.2.3 Divides stochastically the guinea pig into 3 groups: Normal group, surgery group, thrombus group.With the fore-mentioned method manufacture guinea pig AICA embolism chronic model, around the experiment, tests latter 7 day, 30 day of survey guinea pig, the distortion product otoacoustic emission (DPOAE), and examines the cochlea organization hyperoxide mutase the content of the superoxide dismutase(SOD), around the experiment takes the basilar membrane silver nitrate dyeing optical and observe by microscope.3 Results3.1 The dissection guinea pig AICA observation, in 30 guinea pigs approximately some 18 AICA is apart from foramen occipitale magnum's distance to be probably equal to that obviously 2mm,9 guinea pigs the AICA position is apart from foramen occipitale magnum's position is smaller than 2mm,3 guinea pig AICA has not been clear about the exposition in the bone window. 40% or 50% FeCl3 function in the AICA outer wall, its blood stream quantity reduces, the color blanch obviously, perhaps assumes black.3.2 By this method model animal survival time to reach above 7 days, longest may reach for 30 days. This method can manufacture the chronic internal ear ischemia, blocks the internal ear blood stream to be reliable, the thrombus shape is approximate in the human body white thrombus;Outside the laser doppler flowmetry(LDF) discovers the thrombus forms, the cochlea bottom transfers the sidewall blood stream obvious reduction, probably reduces before the thrombus forms 50%;The ABR change in the thrombus forms latter in 4 days to have the obvious change, 4 day of later will restore basically before the technique the level.3.3 After guinea pig thrombus model building, DPOAE in 7 days cannot draw out, 14 days later may draw out, after in 30 days, may also draw out the DPOAE;The thrombus group cochlea organizes the content of SOD assumes the obvious declining trend, in tests the latter 7days also to have the restoration, 30 days restore basically before the technique the level;The basilar membrane shop piece experiments the latter 7 days damage to be heavy obviously, 30 days also cannot restore the normal shape.4 Conclusions4.1 The AICA's diameter of guinea pig does not surpass 0.5mm generally, it branches out from BA, generally the two-sided symmetry, the position is inconstant, the approximately 60% positions are apart from foramen occipitale magnum≥2mm, other parts in 2mm, have not seen AICA individually in the bone window;40%FeCl3 and above may succeed in inducing the thrombus of blood vessel.4.2 In guinea pig AICA may manufacture the chronic internal ear ischemia with 40%FeCl3 embolism's method, The animal survives above for 7 days, longest may reach for 30 days, definitely may satisfy the chronic ischemia model the time request.This method blocks the internal ear blood stream to be quite reliable, the thrombus mode of formation conforms to the pathology physiological process, the surgery operation has the feasibility, easy to grasp, can provide the good animal model regarding the clinical research related internal ear microcycle barrier diseases.4.3 In the experiment ABR changes extensively possible and the blood vessel passes perhaps the corresponding collateral circulation commutation again related;DPOAE restores explained that the outer hair cell's anemic damage, is may achieve the retention function maximum limit through organism own repair the goal;After the ischemia, active oxygen species increase, consumes massive SOD, therefore displays for its content obvious drop, explained that the active oxygen species participates in or the aggravation internal ear ischemia damage, and sends the sense of hearing function barrier;Basilar membrane shop piece obviously outside hair cell's cilium lodging, arrangement disorder, even hair ischemia damage firstly to affect is outside the hair cell;Synthesizes the analysis to be possible to obtain the internal ear function the change to be earlier than the shape change, and can also explain what DPOAE reflect is the entire outer hair cell's function, but is not the single outer hair cell's function.