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Glutamic acid (Gul) is the primary endogenous excitatory neurotransmitter in thecentral nervous system. Under normal condition, the Gul can improve and protect thefunctionofcentral nervecell,buttheexcessGul isexcitatorytoxictothecentralnervoussystem. Gul is also the important neurotransmitter in retina nerval circuit, the exogeneticGul may cause the ganglion cell of animal retina damage. Based on chick embryos, inthis study, in order to study the expression of Bax, c-Fos, AQP-2 and RT97 in the chickretina during embryo development who taken the excess mono sodium L-glutamate(MSG) by immunohistochemistry, to provide reference for the research on neurobiologyanddevelopmentalbiology.METHODSGot the fertilized egg from Lanzhou Hua Long poultry farm, hatched them in theconstant temperature incubator (temperature 37℃, relative humidity 40-60%) to theeighthday,dividedintofivegroups: thecontrol group(normal saline),0.1,0.4,0.7and1mg/ml MSGconcentration groups. Upon yolk-sac inoculation of embryonated eggs, thedosage was 0.2ml every single eggs. Respectively got the eye of the chick embryo, onday12, 15, 18, 21 of chick embryo, got 5 eggs on each dayof each concentration group.Conventional fixed and embedded (slices of 7μm), detected the expression of the Bax,c-Fos, AQP-2 and RT97 by SP and SABC method. The study for Quantitative AnalysisoftheresultsofimmunohistochemistrybyYA-G5000ImageSoft.RESULTS1. Bax was weakiy positive expressed in the chicken embryos of day 12 and 15,next to the high concentration groups which strongly positive expressed were in thechicken embryos of day 18 and 21. The expression only concentrated in thephotoreceptor cell layer (PRL), the immuno-positive expression enhanced with thedosageprogressivelyincreased.2. c-Fos was expressed in the chicken embryos of day from 12 to 21, whichconcentrated in the PRL, the lower margin of inner nuclear layer (INL) and the ganglioncell layer (GCL). The highest level on day 12, but on day 15, 18 and 21 was differentlydecreased. The immuno-positive expression increased with the dosage progressivelyincreased. 3.AQP-2wasexpressed fromtheday12to21of chickembryos, whichconcentratedinthemedial andlateral oftheretina.Thestronglypositive,positiveandweaklypositiveexpressionwas detected from margintocentre presented.Theexpression ofAQP-2werepositive in the PRL, the lower of INL and GCL, some were the strongly positive. In all,the expression of day 12 and 15 were strongly, but no a dose dependent, and theexpressiondecreasedgraduallywiththedosageincreasedondayfrom18to21.4. The RT97 was expressed in the retina from the day 12 to 21 of chick embryos.The expression of 12 day embryos concentrated in the nerve fibers layer (NFL), innerplexiform layer (IPL) and INL, and some RT97 positive cells interspersed in the outernuclearlayer(ONL).Thepositiveexpressionof15dayembryosconcentratedintheNFLand IPL, some positive cells interspersed in the INL and ONL. Shifted to the undersideof INL, the positive expression was reduced. The expression of 18 and 21 dayconcentrated in the NFL, IPL and outer plexiform layer (OPL), which were all stronglypositive. The expression of RT97 enhanced with the development period shiftingdownward,decreasedwiththeincrementofMSGdose.CONCLUSIONS1. The retinal injury caused by the neurotoxicity indused by the exogenoud MSGwasconsistentwiththepreviouslyexperimentalresult.2. The expression of the Bax caused by the neurotoxicity enhanced with thedevelopmentperiodshiftingdownwardandtheincrementofMSGdose.3 The expression of the c-Fos caused by the neurotoxicity enhanced with thedevelopmentperiodshiftingdownwardandtheincrementofMSGdose.4. The expression of AQP-2 was strongly in the retina of chick embryos. Theexpression in the forepart of development was strong than the later and weakened withthedosageprogressivelyincrease.5. The RT97 has the massive expression in the retina of chick embryo, whichenhanced with the development period shifting downward, decreased with the incrementofMSGdose.
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