Consequences of neonatal hypoxia on rat behavior

Abstract

Prenatalna hipoksija stanje je smanjene opskrbe fetalnih tkiva kisikom koje moţe dovesti do oštećenja organa s dugoročnim posljedicama. Kod oštećenja mozga moţe doći do mentalne retardacije, cerebralne paralize, epilepsije i poremećaja ponašanja. Zbog toga se radi velik broj istraţivanja u kojima vaţnu ulogu imaju animalni modeli, od kojih se najčešće koristi štakor. U neonatalnog štakora, stadij razvoja mozga odgovara stadiju razvoja mozga fetusa čovjeka od 23. do 34. tjedna trudnoće, kad najčešće dolazi do problema s hipoksijom. Dosadašnja istraţivanja koristila su invazivne modele hipoksije kod kojih je ponekad teško zaključiti je li neka promjena rezultat hipoksije ili samog operacijskog zahvata. Stoga je cilj ovog istraţivanja bio razviti neinvazivni model te utvrditi postoje li promjene u lokomociji, anksioznom, eksploratornom i socijalnom ponašanju te učenju u mladih štakora, izloţenih hipoksiji u normobaričnoj komori prvog postnatalnog dana. U ovom smo diplomskom radu mladunce štakora od 33. do 45. postnatalnog dana podvrgnuli bateriji testova ponašanja: otvoreno polje, ploča s rupama, T-labirint i društveni odabir. Razina lokomotornog gibanja, anksiozno i eksploratorno ponašanje nisu se razlikovali izmeĎu skupina. U odnosu na kontrolnu skupinu, skupina izloţena hipoksiji imala je značajno manji broj točnih odabira u T-labirintu, a muţjaci i produljeno vrijeme istraţivanja druge jedinke u testu društvenog odabira. Rezultati upućuju na zaključak da neonatalno izlaganje štakora hipoksiji smanjuje sposobnost prostornog učenja i povećava socijabilnost u muţjaka.Prenatal hypoxia is a state of reduced oxygen supply to fetal tissue that can lead to organ damage with long-term consequences. Brain damage can lead to mental retardation, cerebral palsy, epilepsy and behavioral disorders. For this reason, a large amount of research has been done on animal models, especially rats. In the neonatal rat, the stage of brain development matches the stage of brain development in the human fetus from the 23rd to the 34th week of pregnancy, when problems with hypoxia most often occur. Disadvantage of previously used invasive models of hypoxia is a difficulty to conclude whether the observed changes are the result of hypoxia or the operation itself. Therefore, the aim of this study was to develop a non-invasive model and to determine possible changes in locomotion, anxiety-like, exploratory and social behavior, and learning in young rats exposed to hypoxia in the normobaric chamber on the first postnatal day. In this study, young rats underwent the battery of behavioral tests: open field, hole board, T-maze and social choice, from the 33rd to the 34th postnatal day. The level of locomotion, anxiety-like and exploratory behavior did not differ between the groups. Compared to the control group, the hypoxia-exposed group had a significantly smaller number of correct choices in the T-maze. In addition males from the experimental group displayed prolonged research time of the conspecific in the social choice test. The findings suggest that the exposure of neonatal rats to hypoxia reduces the ability of spatial learning and increases the sociability in males