Ökaryotik modelde cisplatin antitümör ajanının elektron transport sistemi üzerine etkisinin araştırılması

Erkek Sprague Dawley yetişkin sıçanlarının dokularından postmitotik hücrelerden oluşan beyin ve kalp ve bu dokularla birlikte yavaş hücre bölünmesine sahip karaciğer ve böbrek dokularının yanı sıra akciğer dokusunda, antitümör ajanı sisplatin, elektron transport sistemi enzimi; süksinat dehidrogenaz (SDH), adenine nükleotid seviyeleri, katalaz aktivitesi ve lipid peroksidasyon düzeylerine olan toksik etkisileri çalışılmıştır. Sisplatin seviyeleri karaciğerde yüzde otuz sekiz ppm/gr olarak maksimum seviyeye ulaşmıştır ve böbrek, beyin, akciğer ve kalpte sırasıyla yüzde otuz altı, yüzde yirmi dört, yüzde yirmi dört ve yüzde onbeş ppm/gr olarak belirlenmiştir. Bu sonuçlar sisplatinin tüm dokulara transportunun olduğunu göstermektedir. Karaciğer, akciğer, kalp, beyin ve böbrekteki SDH aktiviteleri sırasıyla, yüzde altmış altı, yüzde kırk dokuz, yüzde kırk dört, yüzde kırk yedi, yüzde altmış üç oranlarında birinci günlerde kontrol gruplarına kıyasla azalış göstermiştir. Bu azalış birinci günün ATP seviyelerindeki yüzde elli üç, yüzde seksen üç, yüzde altmış iki, yüzde otuz ve yüzde yirmi dört azalışı ile ilişkilidir. Bu sonuçlar ışığında sisplatinin SDH enzim aktivitesi ve ATP düzeylerinin inhibisyonunu indüklediği önerilmektedir. Bununla birlikte, bir antioksidant enzim olarak CAT aktivitesi dokulara bağımlı olarak farklılıklar göstermektedir. LPO seviyeleri birinci günde sisplatin toksisitesine bağlı olarak sırasıyla karaciğer, akciğer, kalp, beyin ve böbrek dokularında kontrole kıyasla bir onda dört, bir onda dört, bir onda beş, bir onda iki ve bir onda beş kat artış göstermiştir. Sisplatin uygulanan dokularda birinci gündeki LPO seviyelerinin kontrole kıyasla yüksek olması sisplatin indüklü toksisiteyi göstermektedir. Bu sonuçlar sisplatin toksisitesine karşı antioksidant sistemin yeterli olmaması ile açıklanabilir. Bu yüzden çalışmanın ikinci aşamasında enzimatik vii olmayan bir antioksidant olan kapsaisin sisplatin ile birlikte enjekte edilerek kapsaisinin bu sistem üzerine etkisi araştırılmıştır. In order to determination of the antitumor agent cisplatin toxicity effect on electron transport chain (ETC) enzymes; succinate dehidrogenase (SDH), adenine nucleotide levels as well as catalase (CAT) and lipid peroxidation (LPO) levels of five different tissues, three of which are composed of post mitotic cells (brain, heart) and two of slowly dividing cells (liver and kidney) as well as lung tissues of Male Sprague Dawley adult rats, were investigated with respect to various days. Cisplatin levels reached to maximum in liver as zero point thirty eight ppm/gr tissue and the levels were ordered as kidney, brain, lung and heart as zero point thirty six, zero point twenty four, zero point twenty four and zero point fifteen ppm/gr tissue, respectively. The results shows that cisplatin transported all studied tissues. In the present study, the SDH activities of liver, lung, heart, brain and kidney decreased sixty six, fourty nine, fourty four, fourty seven, sixty three percent compared to control at first day. These decreases were accompanied by ATP levels as fifty three, eighty three, sixty two, thirty, twenty four percent at first day. The results may suggest that cisplatin agent induce the inhibition of SDH enzyme activity in addition ATP levels. Nevertheless, as an antioxidant enzyme CAT activity showed different trends depending on the tissue. LPO levels increased depending on cisplatin toxicity zero point four-fold, zero point four-fold, zero point five-fold, zero point two-fold and zero point five-fold compared with control groups of liver, lung, heart, brain and kidney, at first day respectively. According to the our results, cisplatin induced toxicity in each tissue especially for first day were determined with higher LPO levels, the results can be explained by insufficiency in enzymatic and nonenzymatic antioxidant systems against to cisplatin toxicity therefore in the second last step of the thesis, we added cisplatin with capsaicin which is non-enzymatic antioxidant to determine capsaicin effect on these system. v In general, SDH activity in cisplatin with capsaicin treated tissue increased while CAT activity and LPO levels decreased compared to only cisplatin groups. The results suggest that capsaicin have antioxidant capacity to scavenge ROS to prevent membrane damage

Oxidative stress does not play a primary role in the toxicity induced with clinical doses of doxorubicin in myocardial H9c2 cells

International audienceThe implication of oxidative stress as primary mechanism inducing doxorubicin (DOX) cardiotoxicity is still questionable as many in vitro studies implied supra-clinical drug doses or unreliable methodologies for reactive oxygen species (ROS) detection. The aim of this study was to clarify whether oxidative stress is involved in compliance with the conditions of clinical use of DOX, and using reliable tools for ROS detection. We examined the cytotoxic mechanisms of 2 μM DOX 1 day after the beginning of the treatment in differentiated H9c2 rat embryonic cardiac cells. Cells were exposed for 2 or 24 h with DOX to mimic a single chronic dosage or to favor accumulation, respectively. We found that apoptosis was prevalent in cells exposed for a short period with DOX: cells showed typical hallmarks as loss of anchorage ability, mitochondrial hyperpolarization followed by the collapse of mitochondrial activity, and nuclear condensation. Increasing the exposure period favored a shift to necrosis as the cells preferentially exhibited early DNA impairment and nuclear swelling. In either case, measuring the fluorescence lifetime of 1-pyrenebutyric acid or the intensities of dihydroethidium or amplex red showed a consistent pattern in ROS production which was a slight increased level far from representative of an oxidative stress. Moreover, pre-treatment with dexrazoxane provided a cytoprotective effect although it failed to detoxify ROS. Our data support that oxidative stress is unlikely to be the primary mechanism of DOX cardiac toxicity in vitro