Aim. Study of the relationship between the parameters of free radical oxidation of proteins and lipids in the murine kidneys in the post-resuscitation period after stopping the systemic circulation, depending on their resistance to hypoxia. Methods. The systemic circulation was stopped by intra-thoracic clamping of the neurovascular bundle for 5 minutes, performed under general ether anesthesia in male noninbred white rats, divided after testing into two groups based on resistance to hypoxia. The observation period lasted for 35 days. In the homogenates of kidney tissues, the content of products reactive to tiobarbituric acid, carbonylated proteins, the formation of metal-catalyzed carbonylated proteins and bitirozin were determined. Results. The characteristic manifestation of oxidative stress in the recovery period after stopping blood circulation and resuscitation was found to be reciprocity of the relationship between the levels of lipoperoxidation and oxidative modification of proteins. Highly resistant to hypoxia animals were characterized by high resistance of proteins of kidney tissue to free radical oxidation against the background of high levels of lipid peroxidation. On the contrary, in animals non-resistant to hypoxia, against the background of relatively low values of lipoperoxidation, high levels of oxidative modification of proteins, both initial and induced, were recorded. Conclusion. In post-resuscitation period in highly resistant to hypoxia animals, marked activation of lipoperoxidation occurs accompanied by a transient increase in the carbonylation of proteins in the early observation period; for low-resistant to hypoxia animals high intensity of carbonyl stress against the background of the relative «preservation» of lipid structures of the cell is characteristic, which persists throughout the post-resuscitation period, which can make a significant contribution to kidney damage, increasing the risk of renal failure.
Цель исследования - изучение особенностей динамики показателей свободнорадикального окисления и уровня кортикостероидных рецепторов в легких у животных с разной чувствительностью к гипоксии в постреанимационном периоде. Методика. Эксперимент выполнен на самцах беспородных белых крыс, разделенных по устойчивости к гипоксии на 2 группы: неустойчивые и высокоустойчивые. Остановку системного кровообращения продолжительностью 5 мин моделировали под общим эфирным наркозом (через 1 нед после тестирования на устойчивость к гипоксии) интраторакальным пережатием сосудистого пучка сердца с последующей реанимацией. Через 1, 3, 5, 7, 14, 21 и 35 сут животных под эфирным наркозом декапитировали. В плазме крови определяли содержание кортикостерона и альдостерона, в гомогенатах легких - концентрацию глюкокортикоидных и минералокортикоидных рецепторов, уровни продуктов, реагирующих с тиобарбитуровой кислотой, карбонилированных белков, железозависимое образование битирозина, активность супероксиддисмутазы, каталазы, содержание восстановленного глутатиона. Результаты. Установлено, что для неустойчивых к гипоксии животных характерна высокая интенсивность свободнорадикального окисления, проявляющаяся развитием карбонильного стресса на фоне снижения активности ключевых антиоксидантов и сопряженная с выраженными изменениями динамики кортикостероидных рецепторов: в первые 3 сут постреанимационного периода наблюдалось снижение уровня кортикостероидных рецепторов, а к концу 35-суточного мониторинга значительное нарастание концентрации минералокортикоидных рецепторов. Высокую степень устойчивости к гипоксии отличает относительно низкая интенсивность свободнорадикального окисления, характеризующаяся только усилением липопероксидации за счет адекватной емкости и сохранности водорастворимых антиоксидантных систем, экранирующих белки. В раннем восстановительном периоде это сопровождается сохранением уровня кортикостероидных рецепторов, в позднем - существенным ростом концентрации глюкокортикоидных рецепторов. Заключение. Увеличение содержания глюкокортикоидных рецепторов у высокоустойчивых к гипоксии животных в позднем восстановительном периоде (14-е - 35-е сут) играет важную роль, предположительно путем модулирования течения воспалительного процесса, ограничения неконтролируемых иммунных реакции и повреждение тканей. Следствием значительного нарастания концентрации минералокортикоидных рецепторов у животных с низкой устойчивостью к гипоксии может быть усиление сосудистого ремоделирования и развитие фиброза в легких. Aim. The aim of the study was to characterize changes in free radical oxidation and corticosteroid receptor density in the lungs of animals with different sensitivity to hypoxia in the postresuscitation period. Methods. Experiments were performed on mongrel male white rats divided into two groups based on their hypoxia resistance, non-resistant and highly resistant. One week after testing the rats for resistance to hypoxia, a 5-min arrest of systemic circulation was modeled under ether anesthesia by intrathoracic compression of the vascular bundle of the heart with subsequent resuscitation. The follow-up period was 35 days. At 1, 3, 5, 7, 14, 21, and 35 days, the animals were sacrificed by decapitation under ether anesthesia, and blood and tissue samples were collected. Concentrations of corticosterone and aldosterone were measured in plasma; concentrations of glucocorticoid and mineralocorticoid receptors, thiobarbituric acid reactive substances, and carbonylated proteins, iron-dependent formation of dityrosine, activities of superoxide dismutase and catalase, and concentration of reduced glutathione were measured in lung homogenates. Results. Hypoxia non-resistant rats had a high intensity of free radical oxidation as evident from the development of carbonyl stress associated with decreased activities of key antioxidants and pronounced changes in the dynamics of corticosteroid receptors. A reduced level of corticosteroid receptors was observed in the first three days of resuscitation period and followed by a significant increase in mineralocorticoid receptors at the end of 35-day monitoring. High resistance to hypoxia was characterized by a relatively low intensity of free radical oxidation, evident only from increased lipid peroxidation, due to an adequate capacity and preservation of water-soluble antioxidants. During the early recovery period, high resistance to hypoxia was associated with preserved level of corticosteroid receptors whereas during late recovery, the high hypoxia resistance was associated with a significant increase in the concentration of glucocorticoid receptors. Conclusion. The increased density of glucocorticoid receptors in hypoxia high-resistant animals during the late recovery period (days 14-35) plays an important role, presumably by modulating the inflammatory process and restricting uncontrolled immune responses and tissue damage. The significant increase in mineralocorticoid receptors in hypoxia low-resistance animals may result in stimulation of vascular remodeling and development of pulmonary fibrosis.
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