title: Modification of reperfusion-induced ionic imbalance by free radical scavengers in spontaneously hypertensive rat retina.
abstract: We studied the effects of free radical scavengers, superoxide dismutase (SOD), vitamin E, and EGB 761, on ion shifts (Na+, K+, and Ca2+) induced by ischemia reperfusion in rat retina obtained from spontaneously hypertensive rats. Eyes were subjected to 90 min of retinal ischemia followed by 24 h of reperfusion. Two basic protocols were used: (1) chronic application, in which rats received SOD (7500, 15,000, and 30,000 U/kg, i.v.), vitamin E (50, 100, and 200 mg/kg, i.v.), and EGB 671 (50, 100, and 200 mg/kg, orally) for 10 d, respectively; and (2) acute administration, in which 7500, 15,000, and 30,000 U/kg of SOD, 50, 100, and 200 mg/kg of vitamin E, and 50, 100, and 200 mg/kg of EGB 761 were administered after an ischemic episode, at the onset of reperfusion, respectively. In the drug-free control group, 90 min ischemia followed by 24 h of reperfusion resulted in an accumulation of retinal sodium and calcium from their nonischemic control values of 76 +/- 4 and 3.2 +/- 0.1 mumol/g dry weight to 112 +/- 6 (p < .001) and 6.2 (p < .001) mumol/g dry weight, respectively. Tissue potassium loss was also observed in this model of retinal ischemia reperfusion, and after 90 min ischemia followed by 24 h of reperfusion potassium content was significantly reduced from its nonischemic control value of 266 +/- 5 to 207 +/- 6 (p < .001) mumol/g dry weight. The chronic administration of SOD, vitamin E, and EGB 761 dose dependently reduced the reperfusion-induced ionic imbalance and improved the recovery of retinal ion contents.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Clinic of Ophthalmology, Medical School, Szeged, Hungary.
authors.forename: M E
authors.initials: ME
authors.lastname: Szabo
authors.forename: M T
authors.initials: MT
authors.lastname: Droy-Lefaix
authors.forename: M
authors.initials: M
authors.lastname: Doly
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers; D005609:Free Radicals; D020441:Ginkgo biloba; D006973:Hypertension / Q000150:complications*; D008297:Male; D010936:Plant Extracts / Q000008:administration & dosage / Q000627:therapeutic use; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D015427:Reperfusion Injury / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism*; D012160:Retina / Q000378:metabolism*; D012171:Retinal Vessels; D012964:Sodium / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000008:administration & dosage / Q000627:therapeutic use; D014810:Vitamin E / Q000008:administration & dosage / Q000627:therapeutic use; D000096983:Ginkgo Extract
chemical_list: D002118:Calcium; D016166:Free Radical Scavengers; D005609:Free Radicals; D010936:Plant Extracts; D011188:Potassium; D012964:Sodium; D013482:Superoxide Dismutase; D014810:Vitamin E; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract