Melatonin prevents inflammation and oxidative stress caused by abdominopelvic and total body irradiation of rat small intestine

Abstract

We investigated the day-night differences in intestinal oxidativeinjury and the inflammatory response following total body (TB) or abdominopelvic (AP) irradiation, and the influence of melatonin administration on tissue injury induced by radiation. Rats (male Wistar, weighing 220-280 g) in the irradiated groups were exposed to a dose of 8 Gy to the TB or AP region in the morning (resting period -1 h after light onset) or evening (activity span -13 h after light onset). Vehicle or melatonin was administered immediately before, immediately after and 24 h after irradiation (10, 2.0 and 10 mg/kg, ip, respectively) to the irradiated rats. AP (P < 0.05) and TB (P < 0.05) irradiation applied in the morning caused a significant increase in thiobarbituric acid reactive substance (TBARS) levels. Melatonin treatment in the morning (P < 0.05) or evening (P < 0.05) decreased TBARS levels after TB irradiation. After AP irradiation, melatonin treatment only in the morning caused a significant decrease in TBARS levels (P < 0.05). Although we have confirmed the development of inflammation after radiotherapy by histological findings, neither AP nor TB irradiation caused any marked changes in myeloperoxidase activity in the morning or evening. Our results indicate that oxidative damage is more prominent in rats receiving TB and AP irradiation in the morning and melatonin appears to have beneficial effects on oxidative damage irrespective of the time of administration. Increased neutrophil accumulation indicates that melatonin administration exerts a protective effect on AP irradiation-induced tissue oxidative injury, especially in the morning.

Protective Effects of Quercetin on Intestinal Damage Caused by Ionizing Radiation

“…Radiotherapy (RT) has an important place in the treatment of abdominopelvic cancers (1). The most important reason for limiting the RT dosage is that, during RT, normal tissues are exposed to radiation along with the cancerous tissues (2,3).…”

“…In previous studies, chemical agents and oral nutritional supplements were used to reduce these complications associated with RT (1,3,7,10,11).…”

İyonize Radyasyon Uygulaması Yapılmış Rat Pineal Bezi Üzerinde Melatoninin Koruyucu Etkisi Var mıdır? Kronobiyolojik ve Elektron Mikroskobik Çalışma

“…Kronobiyolojinin, bu konuyu araştıran alt bilim dalı kronotoksisite olarak adlandırılmaktadır. Radyoterapinin, sıçanlarda uygulanma zamanına bağlı olarak farklı etkiler oluştura-bileceği daha önceki araştırmalarımız sonucunda sunulmuştur [16][17][18] . Literatürde de, 12 saatlik aydınlık-karanlık döngüsünde bırakılan fare ve sıçanlarda, tüm vücuda uygulanan iyonize radyasyonun kronobiyolojik etkisi detaylı olarak derlenmiştir 25,26 .…”

“…Güçlü antioksidan özelliğinin yanı sıra melatoninin radioprotektif (ışıma-koruyucu) etkisi olduğu da bilinmektedir. Daha önce sıçan ince bağırsağında, akciğe-rinde ve testisinde yapmış olduğumuz çalışmalarda iyonize radyasyonun ve melatoninin etkileri araştırılmıştır [16][17][18][19] . Literatürde radyasyonun pineal bez üzerine ince yapı düze-yinde neden olabileceği zedelenme ya da pineal bezden üretilen melatonin miktarındaki değişimler kısmen araştırıl-mış olmakla birlikte 15,20 , radyasyonun oluşturduğu zedelenmenin ve ekzojen uygulanan melatoninin bu zedelenme üzerindeki etkisinin araştırıldığı çalışmalar henüz netlik kazanmamıştır.…”

Apoptotic genes expression in γ-irradiated rats treated with wheat germ oil, zinc and /or bone marrow

“…Following radiotherapy, the risk of normal tissue complication constitutes a significant clinical concern and limits the radiation dose that can be delivered to the patients [2]. Oxidative damage is considered to be one of the most popular and important effects of radiotherapy in the liver that induces generation of reactive oxygen species (ROS), which are per se inducers of apoptosis, and radiotherapy seems to be able to induce an apoptotic program through ROS generation [3]. Gene expression studies have revealed the existence of more than one pathway regulating growth inhibition and apoptotic processes [4].…”