An in vitro rabbit retina model to study electrophysiologic and metabolic function during and following ischemia.
Most in vitro studies involving neuronal ischemia use biochemical measures and/or cell counting to assess cellular death. We describe an in vitro rabbit retina model in which we measured glucose utilization, lactate production, and light-evoked compound action potentials (CAPs) to assess metabolic and functional recovery following ischemia. Under control conditions, retinal glucose utilization and lactate production (n = 7), as well as CAPs (n = 8) remained quite constant for 6-8 h. During ischemia (glucose reduced from 6 to 1 mM and oxygen from 95 to 15%), glucose utilization and lactate production fell to 50%. CAPs fell to 50% in 3-4 min, and to 0% in 8-10 min. Recovery during 3-4 h of 'return-to-control' was dependent upon the length of ischemia. Glucose utilization recovered to 63% after 1 h (n = 4) and to 18% after 2 h of ischemia (n = 6, P < 0.001). Lactate production recovered to 77% after 1 h (n = 4) and to 54% after 2 h of ischemia (n = 6, P < 0.001). CAPs returned to 51, 15, and 0.13% of the control responses after 0.5 h (n = 7), 1 h (n = 8), and 2 h (n = 5) of ischemia, respectively (P < 0.001). This avascular, blood-brain barrier-free preparation provides an opportunity to use both metabolic and functional criteria to test protection against neuronal ischemia.
Quiñones-Hinojosa
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A
Neurophysiology Laboratory, Massachusetts General Hospital and Harvard Medical School, Boston 02114, USA.
Ames
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A
Malek
J Y
JY
Maynard
K I
KI
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D005947:Glucose / Q000378:metabolism*; D007511:Ischemia / Q000378:metabolism* / Q000503:physiopathology; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D008954:Models, Biological; D011817:Rabbits; D012160:Retina / Q000378:metabolism* / Q000503:physiopathology; D012171:Retinal Vessels
D019344:Lactic Acid; D005947:Glucose