Laktasyon Döneminde Oluşturulan Maternal Hipertiroidiye Bağlı Gelişen Öğrenme Bozukluğuna Selenyumun Etkisi

Abstract

Amaç: Hipertiroidi gelişimsel dönemde ve yetişkin dönemde hipokampal-bağımlı öğrenme ve bellek fonksiyonunda olumsuz değişikliklere neden olmaktadır. Bu çalışmada, laktasyon döneminde tiroksin verilen annelerin yavrularında meydana gelen öğrenme bozukluğuna selenyumun iyileştirici etkisi araştırıldı.

Araçlar ve Yöntem: Çalışmada 12 adet gebe sıçan kullanıldı. Gebe sıçanlar rastgele üç gruba (grup başına n=8) ayrıldı: Laktasyon dönemi süresince L-tiroksin (0.2 mg/kg/gün) verilen anne sıçanların erkek yavruları laktasyonel hipertiroidi grubu (LHG)’nu, laktas-yonel hipertiroidi oluşturulduktan sonra 39-60. günler arasında selenyum uygulanan sıçanlar laktasyonel hipertiroidi+selenyum grubu (LH+SeG)’nu, laktasyon dönemi süresince SF uygulanan anne sıçanların yavruları kontrol grubunu (KG) oluşturdu. Uzamsal öğrenme ve bellek fonksiyonu Morris su tankı ile test edildi (her grup için n=16). Tüm ölçümler yavru sıçanların 60-66. gününde yapıldı.

Bulgular: Tek yönlü ANOVA testi ile yapılan post-hoc testi; LHG sıçanların, kontrol grubuna göre daha uzun mesafe kat ederek ve daha uzun süre yüzerek platformu bulduklarını gösterdi (p<0.001). Ayrıca daha yavaş yüzme hızı ve daha yüksek anksiyete bulgusu LHG grubu için diğer bulgulara eşlik etti (p<0.001). LH+SeG sıçanlarda ise kontrol grubundan anlamlı bir farklılık bulunmadı (p>0.005). Probe (bellek testi) testinde hedef kadranda bulunma süresi bakımından gruplar arasında anlamlı farklılık bulunmadı.

Sonuç: Çalışma bulguları, laktasyon döneminde anne sıçanlarda tiroit hormon seviyesi yüksekliğinin, yavru sıçanlarda hipokampal bağımlı öğrenme fonksiyonunda uzun süreli olumsuz etkileri olduğunu ve bu olumsuz etkiler üzerinde selenyumun iyileştirici etkisinin olduğunu göstermektedir. 

Keywords

• Laktasyonel Hipertiroidi
• Selenyum
• Öğrenme ve Bellek
• Morris su tankı testi

The Effect of Selenium on Learning Disability Due to Maternal Hyperthyroidism During Lactation

Abstract

Purpose: Hyperthyroidism causes adverse changes in hippocampal-dependent learning/memory functions in developmental and adult periods. In the present study, the healing effect of selenium was investigated on learning disability in offspring of mothers given L-thyroxine during lactation.

Materials and Methods: 12 pregnant rats were used in the study. The pregnant rats were randomly assigned into three groups (n=8/group): Male offspring of dams administered L-thyroxine (0.2 mg/kg/day) during the lactation was formed as lactational hyper-thyroidism group (LHG), male offspring of dams administered selenium between 39-60 days after induced lactational hyperthyroid-ism was formed as lactational hyperthyroidism+selenium group (LH+SeG), male offspring of dams administered SF during the lacta-tion period was formed the control group (KG). Spatial learning/memory functions were measured with the Morris water maze (n=16/group). All measurements were made when offspring rats were 60-66 days.

Results: Post-hoc test with one-way ANOVA revealed that LHG rats were found on the platform by traveling longer distances and swimming longer than the control group (p<0.001). In addition, slower swimming speed and higher anxiety findings accompanied other findings for the LHG group (p<0.001). There was not any significant difference between the control group and LH+SeG rats. (p>0.005). There was also not any significant difference between the groups in terms of the time spent in the target quadrant in the probe trial.

Conclusion: The study findings show that high thyroid hormone levels in mother rats during lactation have long-term negative effects on hippocampal-dependent learning function in offspring rats, and selenium has a healing effect on these disorders.

Keywords

• Lactational Hyperthyroidism
• Selenium
• Learning and Memory
• Morris water maze

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