Kazime Gonca AKBULUT, Sara YÜZÜAK, Hakan YÜZÜAK

Yaşlanma sürecinde melatoninin pankreas dokusundaki oksidan ve antioksidanlara etkisi

Amaç: Melatoninin; genç (4 aylık) ve orta yaşlı (14 aylık) sıçanlarda pankreas dokusunda malondialdehid (MDA), nitrik oksit (NO) ve glutatyon (GSH) düzeyleri üzerindeki etkisini araştırmak amaçlandı. Yöntemler: Bu deneysel çalışmada genç ve orta yaşlı erkek Wistar albino sıçanlar kullanıldı. Sıçanlar; melatonin verilen genç sıçanlar ve orta yaşlı sıçanlar, melatonin verilmeyen genç sıçanlar ve orta yaşlı sıçanlar şeklinde gruplandırıldı. Melatonin; 10 mg/kg/gün (% 1'lik etanol-phosphate buffered saline (PBS) çözeltisinde, 0,2 cc) olmak üzere, cerrahiye kadar 7 gün boyunca her gün saat 18:00'de subkutan olarak uygulandı. Kontrol grubundaki sıçanlara ise 7 gün süreyle 0,2 cc %1'lik Etanol-PBS, her gün saat 18:00'de subkutan olarak uygulandı. 7. günün sonunda sıçanların kalbinden kan alınıp takiben dekapite edilerek pankreas örnekleri alındı. Alınan örneklerde oksidan stresin göstergesi olarak MDA ve NO düzeyleri ve antioksidan etkinliği olan GSH düzeyi ölçüldü.Bulgular: Genç sıçanların kontrol ve deney grupları arasında NO ve MDA düzeyleri açısından istatistiksel olarak anlamlı fark bulunmadı. Kontrol grubu ile karşılaştırıldığında, genç sıçanların melatonin grubunda pankreas GSH düzeyi anlamlı olarak yüksekti. Orta yaşlı sıçanların kontrol ve melatonin grubu karşılaştırıldığında; pankreas NO düzeyinde anlamlı azalma, pankreas GSH düzeyinde anlamlı artma varken; pankreas MDA düzeyindeki azalma anlamlı değildi. Genç ve orta yaşlı sıçanların kontrol grupları karşılaştırıldığında, pankreas MDA düzeyleri arasında anlamlı bir artış bulundu. Pankreas NO ve GSH düzeyleri, hem genç ve hem de orta yaşlı sıçanların kontrol grubunda istatistiksel olarak anlamlı değişiklik gözlenmedi.Sonuç: Yaşlanma ile pankreas dokusunda serbest radikaller artarken; antioksidan savunma kapasitesi azalmaktadır. Ekzojen melatonin, serbest radikal düzeylerini azaltması ve antioksidanların etkisini arttırması sayesinde, oksidatif strese karşı pankreası koruyabilir.

The effects of melatonin on the oxidants and antioxidants in the pancreatic tissue during the aging process

Objective: To investigate the effect of melatonin on the levels of malondialdehyde (MDA), nitric oxide (NO) and glutathione (GSH) of pancreas tissues at young (4 months) and middle-aged (14 months) rats. Methods: Young and middle-age male Wistar albino rats were used in this experimental study. Rats were divided into two groups: melatonin applied; young rats , middle-aged rats and melatonin was not applied; young rats and middle-aged rats . Melatonin was administered at a dose of 10 mg/kg/day in 0.2 cc-% 1 ethanol-phosphate buffered saline (PBS) solution via subcutan way for 7 days at 18:00 until surgery. In control group, 0.2 cc-%1 Ethanol-PBS was applied for 7 days at 18:00. At the end of seven days, MDA, NO levels which are indicators of oxidant stress and GSH were detected. Results: Although there were no significant difference between control and experiment group for the NO and MDA level of melatonin group of young rats, there were significantly difference in the GSH levels of pancreas tissues for melatonin levels. NO levels of the pancreas tissues were significantly reduced and GSH levels were significantly increased in the melatonin group of middle aged rats compared to the control group. The MDA levels of pancreas tissues were significantly increased in the middle aged control group compared to young control group. The MDA levels of pancreas tissues were not significantly different in melatonin group of middle-aged compared to control group. The NO and the GSH levels of the pancreas tissues were not significantly different between the control groups of young and middle aged rats. Conclusion: Aging may be related with an increase in free radicals and a reduction in the antioxidant capacity of the tissues and exogenous melatonin may play a protective role in aging by means of its action on free radicals.

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