Early Life Stress and Their Effects: Maternal Separation

Abstract

Negative experiences in early life periods are associated with an increase in incidences of psychopathological conditions including depression and anxiety. It has been reported that prenatal or early postnatal stressful environments impair the development and cause life-long health problems, and they particularly result in increased susceptibility to mental disorders. Chronic effects of the different manipulations on postnatal relationships between mother and pups have experimentally been studied for over 50 years in rats. As early life stress model; maternal separation ​​ MS and maternal deprivation MD has mainly been studied in mice and rats. MS and MD are defined as the separation of newborns from mothers for 3 h/day between postnatal 2nd and 14th days and 24 h in the postnatal 9th day, respectively. Using MS and MD experimental models in mice and rats, the effects of neonatal stress on behavioral and endocrine responses, etc. have been investigated in adults used as particularly to investigate. Rodents are dependent on their mothers during early postnatal 3 weeks, and particularly the first 2 week is critical for the development of the brain in rats. While the development of the brain reaches to its peak in the 9th month of pregnancy in man, this occurs during the postnatal 2nd week in rats. MS occurring in early life period can lead to consistent morphologic changes in the brain. Studies reveal that MS can cause lifelong hyperactivity in the hypothalamic–pituitary–adrenal HPA axis and long term MS induces permanent changes in serotonergic, noradrenergic, dopaminergic, GABAergic, glutamatergic systems and endocannabinoids systems and in amounts of BDNF. Conclusion: In present review, MS and MD have been discussed as early life stress experiences regarding their effects on neuronal, immune, endocrine, reproductive, and gastrointestinal systems and microbiota, metabolism, energy homeokinesis, metabolic syndrome, and body weight.

Keywords

• Maternal Separation,Early Life Stress,Behaviour,animal model

Erken Yaşam Stresi ve Etkileri: Maternal Separasyon

Öz

Özbilgi/Amaç: Yaşamın erken dönemlerindeki kötü deneyimler sonraki yaşam süreçlerinde depresyonu ve anksiyeteyi de içeren psikopatolojik durumların insidansını artırmaktadır. İnsanlarda prenatal veya erken postnatal stresli bir çevrenin gelişmeyi olumsuz etkilediği ve yaşam boyu sağlık problemlerine neden olduğu, özellikle de mental hastalıklara yatkınlığı artırdığı rapor edilmiştir. Sıçanlarda anne-yavru ilişkisine postnatal manipülasyonların kronik etkisi 50 yılı aşkın süredir deneysel olarak çalışılmaktadır. Erken yaşam stresi modeli olarak fare ve sıçanlarda maternal separasyon MS ve maternal deprivasyon MD protokolleri yaygın şekilde kullanılmaktadır. MS postnatal 2-14. günler arasında günde 3 saatlik anneden ayırma, MD ise postnatal 9. günde 24 saatlik anneden ayırma periyodu olarak tanımlanmaktadır. Fare ve sıçanda MS ve MD deney modelleri kullanılarak insanlarda neonatal stresin yetişkin dönemdeki etkileri davranış, endokrin cevap, vb. incelenmektedir. Rodentler postnatal ilk 3 haftalık dönemde annelerine bağımlıdır ve özellikle ilk 2 hafta sıçan beyninin gelişmesinde kritik öneme sahiptir. Beyin gelişimi insanlarda gebeliğin 9. ayında pik yaparken, sıçanlarda postnatal 2. haftada gerçekleşmektedir. Erken dönemde yaşanan bir MS beyinde kalıcı morfolojik değişiklikler oluşturabilir. Çalışmalar MS’in yaşam boyu hipotalamo-hipofizer-adrenal HPA eksenin hiperaktivitesine neden olabildiğini ve uzun süreli MS’in beyin bölgelerinin serotonerjik, noradrenerjik, dopaminerjik, GABAerjik, glutamaterjik ve endokannoboid sistemler ile BDNF miktarlarında kalıcı değişikliklere neden olduğunu ortaya koymaktadır. Sonuç: Bu derlemede bir erken yaşam stresi modeli olarak MS ve MD; nöral, immun, endokrin, üreme, gastro-intestinal sistem, intestinal mikrobiyota, enerji döngüsü, metabolik süreçler, metabolik sendrom ve vücut ağırlığı üzerine etkileri yönünden değerlendirilmektedir.

Anahtar Kelimeler

• Maternal separasyon,erken yaşam stresi,davranış,hayvan modeli

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