Evaluation of Oxidant Injury Induced by Irradiation in Brain Tissues of Rats of Different Ages

Abstract

Objectives: We aimed to evaluate the age-related changes of oxidative injury in the brain tissues of rats produced by radiotherapy that is widely used on cancer treatment. Study Design: Fifty-five male Wistar albino rats [ages of rats were 1, 4, 12 weeks (n=10) and 1 year (n=5)] were divided into four groups. Irradiation were performed on a Cobalt-60 unit using a single fraction of 8 Gy. The brain tissues were homogenized and divided into two portions. One portion was used for the measurement of the malondialdehyde (MDA). The other portion was used for the measurement of the protein concentration, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx) enzyme activities. Results: The SOD activity decreased significantly in 1-week-old rats (p<0.05). The decreases in GSHPx and CAT activities were more obvious in 1-week and 1-year-old rats than that in others. No significant changes were observed in adolescent and adult rats. The MDA levels of all groups increased. The highest MDA levels were seen in 1-year-old rats (p<0.05). Conclusion: Ionizing radiation used in radiotherapy affected antioxidant systems and increased MDA levels. These changes were more in the 1-week and 1-year-old rats than in others. This can be due to incomplete development of many systems in newborn rats and the loss of physiological capacities associated with aging in 1-year-old rats. Turkish Başlık: Farklı Yaşlardaki Ratların Beyin Dokularında Radyasyonla İndüklenen Oksidatif Hasarın Değerlendirilmesi Anahtar Kelimeler: Radyoterapi; yaşlanma; oksidan hasar; beyin; serbest radikaller Amaç: Bu çalışmada, kanser tedavisinde yaygın olarak kullanılan radyoterapinin farklı yaşlardaki ratların beyin dokusunda oluşturduğu oksidatif hasarın değerlendirilmesi amaçlandı. Çalışma Planı: Elli beş Wistar albino tipi erkek rat, 1, 4 ve 12 haftalık (n=10) ve 1 yaş (n=5) olmak üzere dört gruba ayrıldı. Tüm gruptaki ratlara Co-60 cihazı ile 8 Gy tek fraksiyon radyasyon uygulandı. Ratların beyin dokuları homojenize edilerek ikiye ayrıldı. Bir yarısı ile malondialdehid (MDA) ölçümü yapıldı. Diğer yarısından elde edilen süpernatant ile protein miktar tayini yapıldı, süperoksit dismutaz (SOD), katalaz (CAT), glutatyon peroksidaz (GSHPx) aktiviteleri ölçüldü. Bulgular: SOD aktivitesinin 1 haftalık ratlarda anlamlı derecede azaldığı bulundu (p<0.05). GSHPx ve CAT aktivitesindeki azalma 1 haftalık ve 1 yaşındaki ratlarda daha belirgindi. Ergen ve erişkin ratlarda önemli değişmeler olmadı (p<0.05). MDA düzeyinde tüm yaş gruplarında artma gözlendi. En yüksek MDA düzeyi 1 yaşındaki ratlarda gözlendi (p<0.05). Sonuç: Radyoterapide kullanılan iyonize radyasyon antioksidan sistemleri etkilemekte ve doku MDA düzeylerini artırmaktadır. Bu değişiklikler 1 haftalık ve 1 yaşındaki ratlarda daha fazladır. Bu durumun yeni doğan ratlarda henüz birçok sistemin tam olarak yerleşmemiş oluşundan ve 1 yaşındaki ratlarda ise yaşlanmaya bağlı olarak ortaya çıkan fizyolojik kapasitedeki kayıplardan kaynaklandığını söyleyebiliriz.

Keywords

• Radiotherapy; aging; oxidant injury; brain; free radicals

Farklı Yaşlardaki Ratların Beyin Dokularında Radyasyonla İndüklenen Oksidatif Hasarın Değerlendirilmesi

Öz

Anahtar Kelimeler

• Radyoterapi, yaşlanma, oksidan hasar, beyin, serbest radikaller.

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