Observation Of Behavior And Glut3,Glut4,APP,Insulin Receptor The Vestibular Nucleus,Hippocampal And Cerebellar Paraflocculus Of Distribution Changes In Diabetic Rats With Unilateral Labyrinth Destruction

Objective1.To explore the effect of diabetes to vestibular reflex pathway and vestibular compensation through analyzing related indexes of static vestibular compensatory and vestibular muscle evoked potential in diabetic rats.2.To explore the mechanism and effect of diabetes to vestibular compensation from the cell energy metabolism aspect by detecting the expression of glucose transporter 3(GLUT3)and glucose transporter 4(GLUT4)in the area of vestibular nucleus,hippocampus,and cerebellar paraflocculus of the four groups(diabetes group,the control,diabetes operation group,the operation control)before and after unilateral labyrinthectomy3.To explore the possible aging effect of diabetes to some part of vestibular center through detecting the expression of insulin receptor-P mRNA and APP mRNA in the area of vestibular nucleus and cerebellar paraflocculus by using in situ hybridization,and the expression of amyloid beta protein by using immunohistochemical method.Material and MethodsDiabetic rat model was made by giving streptozotocin to male SD rats.They were made into unilateral labyrinthectomy model by surgical damage and chloroform injection into the inner ear.Cervical vestibular evoked myogenic potentials(cVEMP)and the imbalance symptom score were detected at different time points.The diabetic group was randomly divided into two groups,sham operation group and unilateral resection group,at the time point of 12 weeks.The normal rats were randomly divided into two groups,the control and the resection group.Their brains were taken out 24 hours later after the surgery.The brain was sectioned on the basis of rat brain stereotaxic atlas edition 3'.GLUT3,GLUT4,and MOAB in the area of vestibular nucleus and cerebellar paraflocculus were detected by using immunohistochemical method and in situ hybridization.And the the insulin receptor-P mRNA and beta-APPmRNA were detected by using in situ hybridization.The elderly group,made up of male SD rats with 18 months old,was detected by the same method.Results1.CVEMP detection:Since the eighth week,the diabetes group had a higher threshold,longer PI latency and N1 latency compared with and the control(P<0.05).There was no significant difference in P1-N1 wave amplitude between the diabetic group and the control(P>0.05).2.The imbalance symptom score:The differences of the symptom scores(head deflexion,limb abduction,forced circular motion or rolling,nystagmus)between the 12-week diabetic group and the control were statistically significant at each time point since 12 hours after the surger(P<0.05)y.3.The GLUT3 and GLUT4 in vestibular nucleus,hippocampus,and cerebellar paraflocculus were compared among the diabetic sham operation group,operation group,normal control,and the operation control.It was statistically different in the area of vestibular nucleus among the four groups(P<0.05).There was no significant difference of GLUT3 on both sides in diabetic group and normal group after operation(P>0.05).But there was difference between the two groups.Besides,there was no significant difference between the diabetic group and the elderly group(P>0.05).and it was with significant difference between the normal and the elderly group operation group(p<0.01).There was no significant difference of GLUT3 in hippocampus between DM group and DM operation group(P>0.05).However,the difference between/among others were all significantly obvious(P<0.05),such as that between the control and the operation control,among the diabetic group,the control,and the normal operation group,and the difference among the diabetes surgery group,the control,and the normal operation group.There was no significant difference of GLUT3 in cerebellar paraflocculus between DM group and DM operation group(P>0.05).However,the difference between/among others were all significantly obvious(P<0.05),such as that between the control and the operation control,and the differences among the diabetes group,diabetes surgery group,the control,and the normal operation group.There was significant difference of GLUT4 in vestibular nucleus among the four groups(P<0.05).The rank of the mean value:the normal operation group>diabetes group>diabetes surgery group>control.group.There was significant difference of GLUT4 in hippocampus among the four groups(P<0.05).The rank of the mean value:the normal operation group>control group>diabetes group>diabetes group.There was significant difference of GLUT4 in cerebellar paraflocculus among the four groups(P>0.05).There was significant difference of GLUT3 in vestibular nucleus and cerebellar paraflocculus among the four groups according to in situ hybridization(P<0.05),but no significant difference in hippocampus(P>0.05).Besides,there was no significant difference of GLUT4 in vestibular nucleus,cerebellar paraflocculus,and hippocampus among the four groups(P>0.05).4.It was negative of amyloid protein in diabetic group.There was significant difference of APP in vestibular nucleus among the four groups according to in situ hybridization(P<0.05).The rank of the mean value:the diabetes group(57.25)>diabetes surgery group(43.42)>control operation group(44.35)>the control group(32.48).There was significant difference of APP in cerebellar paraflocculus(P<0.05).The rank of the mean value:the diabetes group(27.88)>diabetes surgery group(27.20)>control group(10.25)>the control operation group(8.90).There was significant difference of APP in hippocampus between the diabetes group and the control(P<0.05).There was significant difference of APP in vestibular nucleus among the three groups(P<0.05).The rank of the mean value:the diabetes group(36.32)>the elderly group(29.45)>the young group(22.74).Linear regression analysis:The P1 latency of vestibular muscle evoked potential had a correlation withAPP,but it had no correlation with GLUT3 and GLUT4.However,the N1 latency and the threshold had no similar results.5.There was no significant difference of insulin receptor-P mRNA in vestibular nuclei between diabetic group and elderly group(P>0.05),but with significant difference between diabetic group and the control(P<0.05).There was significant difference between in paraflocculus between diabetic group and the control(P>0.05).Conclusion1.Diabetes will affect cVEMP by increasing the threshold,P1 and N1 wave latency.But it will not affect the amplitude.2.The longer of the diabetes duration is,the longer of the static compensatory time will be.3.The glucose transporter proteins change obviously in the areas of vestibular nucleus,hippocampus,cerebellar Paraflocculus after the unilateral labyrinthectomy,indicating that the cell basic metabolism in these areas may change during the vestibular compensation.Diabetes mellitus has an effect on the expression of glucose transporter 3 and 4 in these areas,which may reduce the neural basic metabolism,and thus play a negative role in maintaining normal vestibular function and compensation4.There is insulin receptor mRNA in vestibular nuclei and paraflocculus,indicating that these areas may be affected by change of surround peripheral insulin and corresponding functional changes might be brought about.Decreased insulin resulted from diabetes might affect the function of these areas.The aging effect of diabetes may be the cause of the increase of beta-APP.The increase of beta-APP may affect the results of cVEMP,and may also affect the central vestibular pathway.