Development of cornel transparency in embryonic chick: Influence of exogenous thyroxine and thiouracil on structure, water and electrolyte content☆

[摘要] Thiouracilandthyroxine(T4)wereinjectedontothechickchorioallantoisatvariousdevelopmentalstagestostudytheireffectsoncornealcellularity,dehydrationandstructure.Corneaswereexcised2–9daysaftertreatmentforhistologicalexaminationandforanalysesofwatercontent,sodiumconcentration[Na+]andpotassiumconcentration[K+].Untreatedchickcorneasshowedthatwatercontentand[Na+]decreasedwithadvancingembryonicage,while[K+]increaseduptostage42andthenrapidlydeclined.Corneasfromembryosinjectedwith10mgthiouracilatstage36hadasignificantlyreduced[K+]atstages40and42.Corneasatstages40,42and45hadasignificantlyelevatedwatercontentwhencomparedwithcontrols.Injectionof15μgofT4priortostage36oratorafterstage40didnotproducesignificantchangesincornealwaterandioniccontentcomparedwithcontrols;injectionof15μgofT4duringthecellproliferationperiodofcornealdevelopment(stages36–40)producedasignificantincreasein[K+].Similarresultswereobtainedincorneasfromembryosinjectedwith1μgofT4.Totalcornealthicknesswasincreasedinthiouraciltreatedcorneas,anddecreasedinT4treatedcorneas.Epithelialgrowthwasmarkedlydecreasedwiththiouraciltreatment,whileT4hadlittleeffect.Itislikelythatthiouraciltreatmentdecreasescelldivisioninthecornea,andpreventsformationoftheepithelialbarrier,whereasT4acceleratestheseprocesses.

[学科分类] 生物科学（综合）