Changes Of Gr And Sr-1a In Cochlear Nucleus And Hearing Impairment In Prenatal Stress Rat Offsprings

Background and objectives:With increasing of contemporary society competition,more and more women get stresses in pregnancy which incidents rate reached 16.5%.Prenatal stress may influence the offspring's brain growth and development,leading to the later dysfunction,even some physiological and anatomical disfigurement.Studies showed that long-term and chronic prenatal stress may influence the offspring's hypothalamic-pituitary-adrenal(HPA) and configuration,metabolize and development of neurons.However,these studies always focus on the offsprings behavior and lerning ability.With the development of the studies,some researchers found that prenatal stress may influence the offspring's auditory system.However there was short of systematic research and study of cochlear nucleus receptor change in prenatal stress.For exploring the hearing system changing and mechanism in prenatal stress,GR and SR-1A roles at the process,this subject was designed to approach the effect on offsping rats auditory system by prenatal stress,with an animal model of prenatal stress by observing the activity change of cochlear nucleus tissue GR and SR-1A,trying to offer theoretical foundation for women's pregnant and confinement psychology health care.Materials and Methods1.30 Adult female SD rats(210-250g).5 Adult male SD rats(270-320g).The appearance that the visual field was filled of spermatozoas in vaginal smear was counted as 0 day of pregnancy.Divide for control group(CON group) at random, moderate stress group(MS group) and later stress group(LS group),10 in each group.The prenatal restrained stress model was adopted.The dams in moderate pregnant(7-13d) and later stage(14-21d) were restrained respectively.Restraint stress three times a day,each restraint stress was 45 minutes long.At birth,litters were randomly culled to 2-3 male offsprings from every nest.The offspring were distributed to three groups(OC,OMS,OLSgroup) according to treatment adult groups,8 in each group(4.34—7.12g).2.Every offsprings group animal were observed development situations which included ear opening and eye opening time.3.Every offsprings group animal(30d) test Auditory brainstem response(ABR) before putting to death separately,write down ABRⅠ,Ⅱ,Ⅲlatency, andⅠ-Ⅱ,Ⅱ-Ⅲ,Ⅰ-Ⅲintervals.4.Every group animal was done endocardial perfusion,turned on cranium and fetched brain stem entering 4%polyformaldehyde phosphate buffer(PH7.4) after ABR testing fixing for one week,the paraffin wax is chartered and buried,cut into slices successively.Each rat selects the specific level namely cochlear nucleus to cut into slices,fetches four sets slices altogether.One was studied with HE dye,one was studied with GR immunohistochemistry dye,one was studied with SR-1A immunohistochemistry dye,doing negative control another set.5.Using Biosens Digital Imaging Systems V1.6 image-quantative analysis system to exam intertgral optical density value of the positive reactivity production of GR and SR-1A in rat's cochlear nucleus of every group.6.Statistical analysis of the experimental data was performed with SPSS15.0 software,adopting one-way ANOVA and correlation analysis,all data show by counting((?)±s),With P<0.05 has statistics meanings for the difference.Results1.Ear opening and eye opening in OC group began earlier than those of OLS and OMS group.The difference has statistics meanings(P<0.05). 2.ABR reflecting threshold increases of group OMS and group OLS,Ⅰ,Ⅱ,Ⅲwave latency,andⅠ-Ⅱ,Ⅱ-Ⅲ,Ⅰ-Ⅲintervals obvious extend,difference compared with group OC having statistics meaning(P＜0.05).3.Group OMS and group OLS rats cochlea nucleus can be seen nerve cell depauperate,The figure and quantity of nerve cell obviously reduced,the cell clearance became broaden and the minority of nuclei shrinked.4.The positive reactivity production of GR and SR-1A in rat's cochlear nucleus assume pale brown under the optics microscope.The intergral optical density value of cochlear nucleus GR and SR-1A in group OMS and group OLS are obviously lower than group OC,namely GR and SR-1A activation are obviously subdued,the difference having statistics meaning(P＜0.05).The intergral optical density value of cochlear nucleus GR and SR-1A in group OLS are obviously lowerer than group OMS,the difference having statistics meaning(P＜0.05).5.The intergral optical density value of cochlear nucleus GR,SR-1A andⅢwave delitescence presented remarkable positive correlation(P＜0.05);The intergral optical density value of cochlear nucleus GR and ABR reflecting threshold presented remarkable positive correlation(P＜0.05);The intergral optical density value of cochlear nucleus SR-1A and ABR reflecting threshold is without obvious correlation (r=0.173,P＞0.05).Conclusions1.The experimental offspring rats have changing of hearing in prenatal stress.2.The experimental offspring rats have changing of development in prenatal stress.3.The experimental offspring rats cochlear nucleus GR and SR-1A expression decreased in prenatal stress,the experimental offspring rat's hearing changing situation and GR and SR-1A expression present obvious positive correlation,which point out that GR and SR-1A play an important role in hearing changing caused prenatal stress.