Lenticular oxygen toxicity.
OBJECTIVE
To investigate the possible toxic effect of oxygen on lenses in an organ culture.


METHODS
Bovine lenses were exposed to four different combinations of ambient pressure and oxygen concentration in an organ culture throughout a 7-day period. Lens transparency, histology, enzymatic activities, and photomicrographs were compared in study and control groups.


RESULTS
No differences were observed between study and control lenses in all measured parameters in a group subjected to a single exposure of 100% oxygen under increased (i.e., hyperbaric) ambient conditions and a group exposed repeatedly to high ambient pressure and normal oxygen partial pressure. Decreased lenticular transparency and enzymatic activities along with structural changes were observed in lenses exposed repeatedly to 100% oxygen concentration under both normal and increased ambient pressures. The observed changes were oxygen-load-dependent: the higher the oxygen partial pressure and the longer the time of exposure, the more severe the changes observed. Optical and structural changes in the lens occurred in a centripetal orientation: the greater the oxygen load, the more central the damage.


CONCLUSIONS
High oxygen load has a toxic effect on bovine lenses in organ culture. These effects appear to be cumulative: the higher the oxygen partial pressure and the greater the number of exposures, the more severe the changes observed in the lenses. Changes marking toxicity follow the route of oxygen diffusion into the lens, from the periphery to the center. Cautious interpretation of the results may indicate a role of oxygen (and/or its derivatives) in human cataract formation.
Schaal
Shlomit
S
Alberto Moscona Department of Ophthalmology, Rambam Medical Center, Haifa, Israel.
Beiran
Itzchak
I
Rubinstein
Irit
I
Miller
Benjamin
B
Dovrat
Ahuva
A
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002417:Cattle; D005979:Glutathione Peroxidase / Q000378:metabolism; D006931:Hyperbaric Oxygenation / Q000009:adverse effects; D007905:Lens Diseases / Q000139:chemically induced* / Q000201:enzymology / Q000473:pathology; D007908:Lens, Crystalline / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D009924:Organ Culture Techniques; D010100:Oxygen / Q000633:toxicity*
D002374:Catalase; D005979:Glutathione Peroxidase; D017301:Ca(2+) Mg(2+)-ATPase; D010100:Oxygen