Publication: Sabit ışığa uzun süreli maruz kalan sıçanlarda melatonin takviyesi ve farklı egzersiz modellerinin kognitif fonksiyon üzerine etkileri
Abstract
Amaç: Uzun süreli sabit ışığa maruz kalarak sirkadiyen aritmi oluşturulan sıçanlarda orta şiddetli sürekli egzersiz, yüksek şiddetli aralıklı egzersiz, ekzojen melatonin takviyesinin kognitif fonksiyon üzerindeki olası etkileri araştırıldı. Gereç ve Yöntem: Sıçanlar kontrol grubu ile birlikte; sedanter, orta şiddetli sürekli egzersiz, yüksek şiddetli aralıklı egzersiz ve bunlara melatonin eklenen gruplar olmak üzere yedi gruba (n=8/ grup) ayrıldı. Kontrol grubu aydınlık/ karanlık döngüde, diğer hayvanlar aydınlık/ aydınlık döngüde barındırıldı. Egzersizler koşu bandında 6 hafta boyunca (5 gün/ hafta) gerçekleştirildi ve son 3 hafta sabit ışık protokolü uygulandı. Işık maruziyeti süresince ilgili sıçanlara her gün intraperitoneal melatonin (10 mg/ kg) enjeksiyonu yapıldı. Çalışan belleği değerlendirmek için obje tanıma testi, uzamsal belleği değerlendirmek için Y-Maze testi; anksiyete düzeylerini değerlendirmek için delikli levha ve artı labirenti testleri uygulandı. Beyin dokularında biyokimyasal ve histolojik değerlendirmeler yapıldı. Bulgular ve Sonuç: Kontrol grubu nöron sitoplazmalarının normal hatlara, sedanter grubun piknotik nükleuslara sahip olduğu belirlenmiş; melatonin bu dejeneratif etkileri azaltmıştır. Egzersiz ve melatonin gruplarının dentat girus bölgesi kontrole benzer bulunup, nörogenezde artış izlenirken; CA3 bölgesinde nörogenez yüksek yoğunluklu egzersizle belirgin olarak arttı. Kognitif fonksiyon sürekli ışık maruziyetiyle sedanter hayvanlarda baskılanmışken, melatonin uygulaması ve/ veya egzersiz uygulamalarıyla geri dönmüştür (p<0.05). Melatonin ve/ veya egzersiz, ışığa maruz kalmayla bozulan uzamsal hafızayı iyileşmiştir (p<0.05-0.001). Anksiyete düzeyi egzersiz uygulamalarıyla azalmıştır (p<0.05-0.01). MPO aktivitesi sirkadiyen aritmi ile artmış, melatonin ile baskılanmıştır (p<0.05-0.001). Sonuçlarımız sirkadiyen aritmi ile baskılanan kognitif fonksiyonun, melatonin ve egzersiz uygulamaları ile iyileştiğini ve nörodejeneratif hasarın toparlandığını düşündürmektedir.
Aim: The possible effects of continuous moderate-intensity training, high-intensity intermittent training, exogenous melatonin supplementation on cognition in rats with circadian arrhythmia caused by long-term constant light exposure were investigated. Material and Method: Rats, including control group, were divided into seven groups (n=8/ group); sedentary, moderate-intensity continuous training, high-intensity intermittent training groups and melatonin added groups. Control group was housed in light/ dark cycle; other animals were housed in light/ light cycle. Exercises were performed on treadmill 5 days/ week for 6 weeks, constant light protocol was applied for last 3 weeks. During light exposure, respective rats received daily intraperitoneal injections of melatonin (10 mg/ kg). Working memory was evaluated with object recognition test, spatial memory was measured with Y-Maze. Anxiety level was evaluated via hole-board and plus-maze tests. Biochemical, histological evaluations were made in brain tissues. Results and Conclusion: Neuron cytoplasms of control had normal lines, while sedentary had pycnotic nuclei; degenerative effects were reduced with melatonin. Brain sections of exercise-melatonin combined groups was found to be similar to control, an increase in neurogenesis was observed. Neurogenesis in CA3 was significantly increased in high-intensity exercise. Cognition was suppressed with light exposure, it returned back with melatonin and/ or exercise (p<0.05). Melatonin and/ or exercise recovered the spatial memory which was declined with light exposure. (p<0.05-0.001). Anxiety level decreased with both exercises (p<0.05-0.01). MPO activity increased with circadian arrhythmia, was suppressed by melatonin (p<0.05- 0.001). Our results reported improvement of suppressed cognition levels, spatial memory with circadian arrhythmia via melatonin and exercise applications, and recovery in neurodegenerative damage.
Aim: The possible effects of continuous moderate-intensity training, high-intensity intermittent training, exogenous melatonin supplementation on cognition in rats with circadian arrhythmia caused by long-term constant light exposure were investigated. Material and Method: Rats, including control group, were divided into seven groups (n=8/ group); sedentary, moderate-intensity continuous training, high-intensity intermittent training groups and melatonin added groups. Control group was housed in light/ dark cycle; other animals were housed in light/ light cycle. Exercises were performed on treadmill 5 days/ week for 6 weeks, constant light protocol was applied for last 3 weeks. During light exposure, respective rats received daily intraperitoneal injections of melatonin (10 mg/ kg). Working memory was evaluated with object recognition test, spatial memory was measured with Y-Maze. Anxiety level was evaluated via hole-board and plus-maze tests. Biochemical, histological evaluations were made in brain tissues. Results and Conclusion: Neuron cytoplasms of control had normal lines, while sedentary had pycnotic nuclei; degenerative effects were reduced with melatonin. Brain sections of exercise-melatonin combined groups was found to be similar to control, an increase in neurogenesis was observed. Neurogenesis in CA3 was significantly increased in high-intensity exercise. Cognition was suppressed with light exposure, it returned back with melatonin and/ or exercise (p<0.05). Melatonin and/ or exercise recovered the spatial memory which was declined with light exposure. (p<0.05-0.001). Anxiety level decreased with both exercises (p<0.05-0.01). MPO activity increased with circadian arrhythmia, was suppressed by melatonin (p<0.05- 0.001). Our results reported improvement of suppressed cognition levels, spatial memory with circadian arrhythmia via melatonin and exercise applications, and recovery in neurodegenerative damage.