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Studies on mechanism of cardiac reperfusion injury
J Mol Cell Cardiol23 (SupplementlI)(1991) 7fl .- REPETITIVE BRIEF ISCHEMIA ENHANCE INDUCTION OF MITOCHONDRIAL MANGANESE SUPEROXIDE DISMUTASE IN CANINE HEART. Hisakazu Fuji, Tsunehiko Kuzuya, Keiichiro Suzuki*, Youngjoon Kim, Hiroshi Oe, Akira Shit-o Hoshida, Naoyuki Taniguchi*, Michihiko Tada, Takenobu Kamada. The Kitabatake, of Biochemistry, Osaka First Department of Medicine and *Department University School of Medicine, Osaka, Japan. Repetitive brief ischemia is known to induce myocardial tolerance to of free radicals, especially superischemic damage. Since generation occurs during reperfusion phase under oxide anion in mitochondria, these conditions, we investigated mitochondrial manganese superoxide dismutase (Mn-SOD) content of canine myocardium after four 5min occluMn-SOD content of inner and outer resion and reperfusion of LAD. gions of ischemic and non-ichemic myocardium was measured by enzymelinked immunosorbent assay. At 3 hours after brief ischemia, Mn-SOD content of ischemic myocardium was decreased slightly. However, Mn-SOD content of ischemic region, especially the inner area at risk (2.8+0.2ug/mg protein, mean+SEM), was increased compared with that of non-ischemic area (2.0?0.2ug/mg protein,p<0.05). These results suggest that mitochondrial Mn-SOD induction induced by brief ischemia plays an important role for myocardial torerance against subsequent ischemia.
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STUDIES ON MECHANISM OF CARDIAC REPERFUSION INJURY. S. Itoh, T. Yanagishita, M. Tomita, S. Mukae, K. Umetsu, S. Koba, H. Suzuki, T. Katagiri, H. Utsumi: A. Hamada" Third Department of Internal Medicine, School of Medicine and Health Chemistry, School of Pharmaceutical Sciences* Showa University, Tokyo, Japan. We studied cardiac reperfusion injury in canine heart with ESR (spin trapping agent :PBN, 50 mg/kg BW). Detection of PBN adduct from right ventricular blood samples after coronary reperfusion was studied in connection with decrease in SR Ca-ATPase activity and degradation of SR protein. To elcidate the mechanism of reperfusion injury, extracted SR and SL were reacted with H202 + Fe3+-ADP or HOCl. Morphological analysis was done by observing appearance of contraction band in myocytes. Five fold increase in PBN adduct than that of control was observed in reperfusion after 10 min of ischemia. No significant decreases in SR Ca-ATPase activity was found in simple ischemia for 10 min, marked reduction in the activity was recognized in reperfusion after 10 min of ischemia without any alteration in SR protein with electrophoresis. SR and SL and 0.1 u&i or 5)&l Ca uptake were inhibited by 0.1 mM or 5 mM H202, respectively, HOCl, respectively. Inhibited SR Ca-ATPase activities by H202 or HOC1 did not bring with any degradation in major ATPase protein with electrophoresis. These results suggest reperfusion after short period of ischemia could be oxidate some molecular level in active site of these enzymes.
EFFECTS OF HYPOCHLOROUS ACID ON Ca2+ TRANSPORT ACTIVITIES OF ISOLATED CARDIAC N. Makino, T. Yanaga, *N. S. SARCOLEMMA. T. Hata, K. Masutomo, K. Yano, H. Nakanishi, Dhalla. Department of Bioclimatology and Medicine, Kyushu University, Beppu, Japan and St. Boniface General Hospital Research Centre *Division of Cardiovascular Sciences, and Department of Physiology and Medicine, University of Manitoba, Winnipeg, Canada. by activated Hypochlorous acid (HOCl) has been suggested to be produced which accumulate in myocardial tissue during post-ischemic reperfusion. neutrophils, In this It is of interest how HOC1 is related to reperfusion injury of h arts. It transport acregard, we investigated the effect of HOC1 on trans-sarcolemmal Ca binding tivities which were Nat-Ca2+ exchange, Ca2+ -pump and L3H] nitrendipine activities. Sarcolemmal vesicles from rat hearts were isolated by the sucrose Just before experiments, HOC1 was prepared by vacuum distillation gradient technique. Addition of HOC1 (0.1-l mM) to of NaOCl adjusted pH 6.2 wit ~+d~~g,suX;;L;,yBCid. This effect of HOC1 was abolished sarcolemma reduced the Nat-Ca Ca2'-stimulated, Mg2'-dependenti;ATPase by addition of 1 mM dithiothreit 1. Similarly, which were refered as Ca -pump activity and ATP-dependent Ca '2t accumulation, were also depressed by the addition of HOC1 in dose &ependent manner (0.01-l activity, transport activities, These results suggest that HOC1 inhibits sarcol$ymal Ca UN). overload during post-ischemic of HOC1 may be responsible for Ca thus, these effects reperfusion injury. s.40
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STUDIES ON MECHANISM OF CARDIAC REPERFUSION INJURY. S. Itoh, T. Yanagishita, M. Tomita, S. Mukae, K. Umetsu, S. Koba, H. Suzuki, T. Katagiri, H. Utsumi: A. Hamada" Third Department of Internal Medicine, School of Medicine and Health Chemistry, School of Pharmaceutical Sciences* Showa University, Tokyo, Japan. We studied cardiac reperfusion injury in canine heart with ESR (spin trapping agent :PBN, 50 mg/kg BW). Detection of PBN adduct from right ventricular blood samples after coronary reperfusion was studied in connection with decrease in SR Ca-ATPase activity and degradation of SR protein. To elcidate the mechanism of reperfusion injury, extracted SR and SL were reacted with H202 + Fe3+-ADP or HOCl. Morphological analysis was done by observing appearance of contraction band in myocytes. Five fold increase in PBN adduct than that of control was observed in reperfusion after 10 min of ischemia. No significant decreases in SR Ca-ATPase activity was found in simple ischemia for 10 min, marked reduction in the activity was recognized in reperfusion after 10 min of ischemia without any alteration in SR protein with electrophoresis. SR and SL and 0.1 u&i or 5)&l Ca uptake were inhibited by 0.1 mM or 5 mM H202, respectively, HOCl, respectively. Inhibited SR Ca-ATPase activities by H202 or HOC1 did not bring with any degradation in major ATPase protein with electrophoresis. These results suggest reperfusion after short period of ischemia could be oxidate some molecular level in active site of these enzymes.
EFFECTS OF HYPOCHLOROUS ACID ON Ca2+ TRANSPORT ACTIVITIES OF ISOLATED CARDIAC N. Makino, T. Yanaga, *N. S. SARCOLEMMA. T. Hata, K. Masutomo, K. Yano, H. Nakanishi, Dhalla. Department of Bioclimatology and Medicine, Kyushu University, Beppu, Japan and St. Boniface General Hospital Research Centre *Division of Cardiovascular Sciences, and Department of Physiology and Medicine, University of Manitoba, Winnipeg, Canada. by activated Hypochlorous acid (HOCl) has been suggested to be produced which accumulate in myocardial tissue during post-ischemic reperfusion. neutrophils, In this It is of interest how HOC1 is related to reperfusion injury of h arts. It transport acregard, we investigated the effect of HOC1 on trans-sarcolemmal Ca binding tivities which were Nat-Ca2+ exchange, Ca2+ -pump and L3H] nitrendipine activities. Sarcolemmal vesicles from rat hearts were isolated by the sucrose Just before experiments, HOC1 was prepared by vacuum distillation gradient technique. Addition of HOC1 (0.1-l mM) to of NaOCl adjusted pH 6.2 wit ~+d~~g,suX;;L;,yBCid. This effect of HOC1 was abolished sarcolemma reduced the Nat-Ca Ca2'-stimulated, Mg2'-dependenti;ATPase by addition of 1 mM dithiothreit 1. Similarly, which were refered as Ca -pump activity and ATP-dependent Ca '2t accumulation, were also depressed by the addition of HOC1 in dose &ependent manner (0.01-l activity, transport activities, These results suggest that HOC1 inhibits sarcol$ymal Ca UN). overload during post-ischemic of HOC1 may be responsible for Ca thus, these effects reperfusion injury. s.40