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Effects of antioxidant agents in protecting the brain against ischemia-reperfusion injury: In vivo and in vitro model studies
156 16.21
Antioxidant Therapy: Ischcmia/Rel~rfusion, Bum/Trauma EFFECT OF SUPEROXIDE DIS~UTASE TREATMENT ON ISCHEffIA REPF~SION INJURY IN TOTAL S~ALL BO~L Takao Ozasa, Sunao Zubet~, ~asayukJ Kimura, ~inoru Hamaguchi, Shigeru Ohwada and Hiromu Natanabe Depertment of Surgery and ~edicine, St.~arianna ~nivercity School of ffedicine, ~iyamaeku Ka~asaki Japan
We studied the effect of Superoxide Dismutase (SOD) treatment on ischemia reperfusion injury in total small bowel. Eleven mongrel dogs underwent total small bowel warm ischemia. Total small bowel warm Jschemia was performed by occlusion of the superior mesenteric artery, vein and a l l collaterals for 60 minutes. The animals were grouped as follows: group ] consited of five cont.~o! dogs, recieving no treatment. Group 2 consisted of six dogs, recieving 5,000 U/~ of SOD via SML just before ecclusion, i ~ e d i at,ely and 30 minutes a f t e r releasing clamp. Morpholegic studies( i.e. microscopic and eiectronmicroscopic) and D-xylose absorption test of both gro~lp 1 and group 2were examined the day before operation, 14 and 28 postoperative days. The 14-and 28-~stoperat ire day's microscopic studies were almost normal structure of beth grnup 1 and gro~p 2. However, the 14-postoperatJve-day's u l t r a s t r u c t u r e of the group l showed d i l a t a t i o n of cell to cell space and fluid accumulation in i n t r a c e l l u l a r space. On the other hand, the group 2 showed almost normal ultrastructure. D-xylose absorption tests of both group ] and gronp 2 were lower than normal control, but not s i g n i f i c a n t differences. D-xylose absorption test of group 1 at 28 postoperative day was lower than group 2, in which D-×ylose test was nearly at normal levels. Our results showed that SOD effectively prevented reperfusion injury in total s~ail bowel.
16.23
hrSOD DOES NOT PREVENT BACTERIAL TRANSLOCATION (BT) IN A BABOON POL YTRAUMA MODEL Heinz Redl, GiJnther Schlag, Harald Gasser, Hans-Peter Dinges*, Keith Radmore**, James Davies** Ludwig Boltzmann Institute fiJr Experimental and Clinical Traumatology, A-1200 Vienna, * Institute for Pathology, University, A-8036 Graz, Austria, ** Roodeplaat Research Laboratories, Sinoville 0129 Pretoria, South Africa We hypothetized that BT occurs as the result of shock related reperfusion injury and tried to attenuate BT with hrSOD. Methods: Our model in EEG-controlled anesthetized baboons involves closed femur fracture, soft tissue injury and hypovolemia (40 mm Hg) over 3 hours, as well as resuscitation over 3 hours (reinfusion shed blood Ringer's solution 1 + 1). In 9 animals hrSOD was infused over 5 hours (6, 30, 120 mg/kg), starting 30 minutes post trauma. 5 animals were used as control shock and 2 as sham animals. BT was assessed with microbiology and histology, radical release with antioxidants (tocopherol, SH groups) and lipid peroxidation (conj. dienes, TBAR, fluorescence) levels in plasma. In additional experiments also splanchnic perfusion was investigated with flow and gut wall pH measurements (tonometer). Results: Incidence of BT was seen in 7 of 9 shock animals with SOD and 4/5 without SOD in blood and tissue samples, both during shock and after reinfusion. Radical related parameters in plasma were not positiv, influenced by SOD. Conclusion: In 80 % of shock animals BT occurred, which was not influenced by hrSOD. Possible explanations 1) BT was ischemia related and not dependent on repedusion. 2) Despite of high conc. of continuously applied hrSOD, radical related plasma parameters were not influenced, which might indicate ineffective action of SOD.
ROLE OF REACTIVE OMYGEN AND FREE RADICALS IN SKIN REACTIONS INDUCED BY UV RADIATION (UVR) M. A. Pathak, Dept. of Dermatology, Harvard Medical School, Boston, MA 02114, U.S.A.
16.22
Sunburn, tanning, skin photosensitization by porphyrins (PP), psoralens (PSO), photoaging (dermatoheliosis), etc., are examples of harmful effects of reactive oxygen and free radicals in skin reactions induced by UVR (290-400nm). Reactive free radicals in hi,nan skin are generated in sunburn reaction; pre-enrichment of skin by free radical scavengers (~-tocopherol acetate (eTCP), B-carotene (8C), potassium sorbate) can minimize sunburn reaction. Photoreactive PSO, PP, and riboflavin u ~ n irradiation (320-400mm) produce reactive O 9 (~O9, 0~, or "OH) that cause: a) skin photosensitization (erythema, ede~na, vesiculation) , b) oxidation of membrane lipids in epidermal microsomes, c) destruction of cytochrcme P-450, and d) inhibition of superoxide dismutase (SOD). These ha{mful reactions were prevented by scavengers of ~Op (e.g., NaNq, BC,aTCP, DABCO, etc.). The in viv~ skin photo = sensitization reaction induced by PSO + UVR in guinea pigs was inhibited by pretreating skin with NAN^, ~TCP, DABCO, BC, and indanethacine. Skin tan~ing reaction, involving photo-oxidation and formation of Semliquinone in melanin, can be blocked by antioxidants such as aTCP, BC, ascorbic acid. Skin photoaging involves the generation of reactive 02 and free radicals by UVR and the formation cross-links in collagen. This process of cross-link~g can be inhibited by selective quenchers of 02, 0;, and free radicals.
EFFECTS OF ANTIOXIDANT AGENTS IN PROTECTING THE BRAIN AGAINST ISCHEMIA-RI~ERFUSION INJURY: IN VIVO AND IN VITRO MODEL S~ODIES Atsuhiro Sakamoto, S. Tsuyoshi Ohnishi and Ryo Ogawa. Philadelphia Biomedical Research Institute, Radnor, PA 19087, USA and Nippon Medical School, Bunkyo-ku, Tokyo, Japan. We have developed simple reproducible in vivo and in vitro models to measure the activity of anti-oxidants to protect the brain against ischemia-reperfusion. In the in vitro model, a r~t was decapitated and the head was kept 37 vC for 30 min. Then, the brain was removed and homogenized in a reaction medium in the absence or presence of antioxidant agents. The suspensions were equilibrated with air for 30 min. In the in vivo model, brain ischemia was induced by the combination of bilateral carotid occlusion and hemorragic hypotension(30 mmHg) for 20 min. Then, the clamps were removed, blood was reinfused and the circulation reestablished. After 20 min., the rat was decapitated and the brain was homogenized. In both models, the anDunt of thiobarbituric acid reactive substance and diene conjugation were measured. Using these methods, we measured the protective effects of MR-356 and -5626 (which are ester-form oligomers of prostaglandin El). We found that MR-5626 was i0 times mere a~tive than MR-356 and protected the brain in the in vivo model from injury at a dose of 9 mg/kg. It was i00 times more effective than SOD in the in vitro model.
16.24
Antioxidant Therapy: Ischcmia/Rel~rfusion, Bum/Trauma EFFECT OF SUPEROXIDE DIS~UTASE TREATMENT ON ISCHEffIA REPF~SION INJURY IN TOTAL S~ALL BO~L Takao Ozasa, Sunao Zubet~, ~asayukJ Kimura, ~inoru Hamaguchi, Shigeru Ohwada and Hiromu Natanabe Depertment of Surgery and ~edicine, St.~arianna ~nivercity School of ffedicine, ~iyamaeku Ka~asaki Japan
We studied the effect of Superoxide Dismutase (SOD) treatment on ischemia reperfusion injury in total small bowel. Eleven mongrel dogs underwent total small bowel warm ischemia. Total small bowel warm Jschemia was performed by occlusion of the superior mesenteric artery, vein and a l l collaterals for 60 minutes. The animals were grouped as follows: group ] consited of five cont.~o! dogs, recieving no treatment. Group 2 consisted of six dogs, recieving 5,000 U/~ of SOD via SML just before ecclusion, i ~ e d i at,ely and 30 minutes a f t e r releasing clamp. Morpholegic studies( i.e. microscopic and eiectronmicroscopic) and D-xylose absorption test of both gro~lp 1 and group 2were examined the day before operation, 14 and 28 postoperative days. The 14-and 28-~stoperat ire day's microscopic studies were almost normal structure of beth grnup 1 and gro~p 2. However, the 14-postoperatJve-day's u l t r a s t r u c t u r e of the group l showed d i l a t a t i o n of cell to cell space and fluid accumulation in i n t r a c e l l u l a r space. On the other hand, the group 2 showed almost normal ultrastructure. D-xylose absorption tests of both group ] and gronp 2 were lower than normal control, but not s i g n i f i c a n t differences. D-xylose absorption test of group 1 at 28 postoperative day was lower than group 2, in which D-×ylose test was nearly at normal levels. Our results showed that SOD effectively prevented reperfusion injury in total s~ail bowel.
16.23
hrSOD DOES NOT PREVENT BACTERIAL TRANSLOCATION (BT) IN A BABOON POL YTRAUMA MODEL Heinz Redl, GiJnther Schlag, Harald Gasser, Hans-Peter Dinges*, Keith Radmore**, James Davies** Ludwig Boltzmann Institute fiJr Experimental and Clinical Traumatology, A-1200 Vienna, * Institute for Pathology, University, A-8036 Graz, Austria, ** Roodeplaat Research Laboratories, Sinoville 0129 Pretoria, South Africa We hypothetized that BT occurs as the result of shock related reperfusion injury and tried to attenuate BT with hrSOD. Methods: Our model in EEG-controlled anesthetized baboons involves closed femur fracture, soft tissue injury and hypovolemia (40 mm Hg) over 3 hours, as well as resuscitation over 3 hours (reinfusion shed blood Ringer's solution 1 + 1). In 9 animals hrSOD was infused over 5 hours (6, 30, 120 mg/kg), starting 30 minutes post trauma. 5 animals were used as control shock and 2 as sham animals. BT was assessed with microbiology and histology, radical release with antioxidants (tocopherol, SH groups) and lipid peroxidation (conj. dienes, TBAR, fluorescence) levels in plasma. In additional experiments also splanchnic perfusion was investigated with flow and gut wall pH measurements (tonometer). Results: Incidence of BT was seen in 7 of 9 shock animals with SOD and 4/5 without SOD in blood and tissue samples, both during shock and after reinfusion. Radical related parameters in plasma were not positiv, influenced by SOD. Conclusion: In 80 % of shock animals BT occurred, which was not influenced by hrSOD. Possible explanations 1) BT was ischemia related and not dependent on repedusion. 2) Despite of high conc. of continuously applied hrSOD, radical related plasma parameters were not influenced, which might indicate ineffective action of SOD.
ROLE OF REACTIVE OMYGEN AND FREE RADICALS IN SKIN REACTIONS INDUCED BY UV RADIATION (UVR) M. A. Pathak, Dept. of Dermatology, Harvard Medical School, Boston, MA 02114, U.S.A.
16.22
Sunburn, tanning, skin photosensitization by porphyrins (PP), psoralens (PSO), photoaging (dermatoheliosis), etc., are examples of harmful effects of reactive oxygen and free radicals in skin reactions induced by UVR (290-400nm). Reactive free radicals in hi,nan skin are generated in sunburn reaction; pre-enrichment of skin by free radical scavengers (~-tocopherol acetate (eTCP), B-carotene (8C), potassium sorbate) can minimize sunburn reaction. Photoreactive PSO, PP, and riboflavin u ~ n irradiation (320-400mm) produce reactive O 9 (~O9, 0~, or "OH) that cause: a) skin photosensitization (erythema, ede~na, vesiculation) , b) oxidation of membrane lipids in epidermal microsomes, c) destruction of cytochrcme P-450, and d) inhibition of superoxide dismutase (SOD). These ha{mful reactions were prevented by scavengers of ~Op (e.g., NaNq, BC,aTCP, DABCO, etc.). The in viv~ skin photo = sensitization reaction induced by PSO + UVR in guinea pigs was inhibited by pretreating skin with NAN^, ~TCP, DABCO, BC, and indanethacine. Skin tan~ing reaction, involving photo-oxidation and formation of Semliquinone in melanin, can be blocked by antioxidants such as aTCP, BC, ascorbic acid. Skin photoaging involves the generation of reactive 02 and free radicals by UVR and the formation cross-links in collagen. This process of cross-link~g can be inhibited by selective quenchers of 02, 0;, and free radicals.
EFFECTS OF ANTIOXIDANT AGENTS IN PROTECTING THE BRAIN AGAINST ISCHEMIA-RI~ERFUSION INJURY: IN VIVO AND IN VITRO MODEL S~ODIES Atsuhiro Sakamoto, S. Tsuyoshi Ohnishi and Ryo Ogawa. Philadelphia Biomedical Research Institute, Radnor, PA 19087, USA and Nippon Medical School, Bunkyo-ku, Tokyo, Japan. We have developed simple reproducible in vivo and in vitro models to measure the activity of anti-oxidants to protect the brain against ischemia-reperfusion. In the in vitro model, a r~t was decapitated and the head was kept 37 vC for 30 min. Then, the brain was removed and homogenized in a reaction medium in the absence or presence of antioxidant agents. The suspensions were equilibrated with air for 30 min. In the in vivo model, brain ischemia was induced by the combination of bilateral carotid occlusion and hemorragic hypotension(30 mmHg) for 20 min. Then, the clamps were removed, blood was reinfused and the circulation reestablished. After 20 min., the rat was decapitated and the brain was homogenized. In both models, the anDunt of thiobarbituric acid reactive substance and diene conjugation were measured. Using these methods, we measured the protective effects of MR-356 and -5626 (which are ester-form oligomers of prostaglandin El). We found that MR-5626 was i0 times mere a~tive than MR-356 and protected the brain in the in vivo model from injury at a dose of 9 mg/kg. It was i00 times more effective than SOD in the in vitro model.
16.24