Juvenil sıçanlarda farklı sosyal etkileşimlerin hipokampal nörogenez ve nöron sayıları üzerindeki etkileri: histolojik ve davranışsal bir çalışma

Abstract

Amaç: Ergenlik, çok sayıda hormonal ve nörokimyasal değişimden etkilenen bir gelişim dönemidir. Bu dönemde akranlarla geçirilen zamanın ve deneyimlerin nörogelişimsel faydaları olduğu bilinmektedir. Hipokampus, doğumdan sonra yeni nöron üretiminin yaşam boyunca devam ettiği ve değişen sosyal etkileşimlere duyarlı bir beyin bölgesidir. Bu çalışmada, değişen sosyal etkileşimlerin sıçan yavrularının hipokampusundaki davranışsal parametreler, doublecortin (DCX) ekspresyonu ve toplam nöron sayıları üzerindeki etkilerini araştırmayı amaçladık. Gereç ve yöntem: 21 günlük erkek ve dişi Wistar albino sıçanlar kontrol, sosyal izolasyon ve çevresel zenginleştirme olmak üzere üç gruba ayrıldı. Sosyal izolasyon ve çevresel zenginleştirme 4 hafta boyunca uygulandı. Davranışsal parametreler bilye gömme, sosyal etkileşim ve açık alan testleri kullanılarak analiz edildi. Davranış testlerinin ardından sakrifiye edilen sıçanların hipokampüsleri çıkarıldı. Parafin kesitlerde Crezil violet boyaması ve yüzen kesitlerde DCX immünohistokimyası yapıldı. Bulgular: Artan sosyal etkileşimlerin ergen sıçanlarda keşif davranışı üzerinde olumlu etkileri olmuştur. Azalan sosyal etkileşimler anksiyete, depresyon davranışları ve lokomotor aktivitede artışa neden olmuştur. Histolojik analiz, çevresel zenginleştirme grubunda dentat girustaki toplam nöron ve DCX-pozitif nöroblast sayısında önemli bir artış olduğunu ortaya koymuştur. Sosyal izolasyon grubunda ise toplam nöron ve DCX-pozitif nöroblast sayısında anlamlı bir azalma gözlenmiştir. Sonuç: Bu sonuçlar, sütten kesme döneminde değişen sosyal etkileşimlerin nörogenez ve DG'daki olgun nöron sayısı üzerinde etkisi olduğunu ve bu etkinin farklı hayatta kalma mekanizmaları tarafından düzenlendiğini göstermiştir.

Keywords

• Hipokampus
• nörogenez
• doublecortin proteini
• sosyal izolasyon
• sosyal etkileşim

Effects of different social interactions on hippocampal neurogenesis and neuron numbers in juvenile rats: a histological and behavioral study

Abstract

Purpose: Adolescence is a period of development affected by numerous hormonal and neurochemical changes. During this period, time spent with peers and experiences are known to have neurodevelopmental benefits. The hippocampus is a brain region where the production of new neurons after birth continues throughout life and is sensitive to changing social interactions. In this study, we aimed to investigate the effects of changing social interactions on behavioral parameters, doublecortin (DCX) expression, and total neuron numbers in the hippocampus of rat pups. Materials and methods: 21-day-old male and female Wistar albino rats were divided into three groups: control, social isolation, and environmental enrichment. Social isolation and environmental enrichment were applied for 4 weeks. Behavioral parameters were analyzed using ball burying, social interaction, and open-field tests. Following the behavioral tests, the rats were euthanized, and their hippocampal tissues were extracted. Cresyl violet staining was performed on paraffin sections, and DCX immunohistochemistry was performed on floating sections. Results: Increased social interactions had positive effects on exploratory behavior in adolescent rats. Decreased social interactions caused anxiety, depression behaviors, and increased locomotor activity. Histological analysis revealed a significant increase in the total number of neurons and DCX-positive neuroblasts in the dentate gyrus in the environmental enrichment group. In the social isolation group, a significant decrease in the total number of neurons and DCX-positive neuroblasts was observed. Conclusion: These results implied that changing social interactions during the weaning period have an effect on neurogenesis and the number of mature neurons in the DG, and this effect is regulated by different survival mechanisms.

Keywords

• Hippocampus
• neurogenesis
• doublecortin protein
• social isolation
• social interaction

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