Abstract
Purpose: :
Epidemiological and clinical observations have indicated a link between heat exposure and cataract. Many workers are exposed to high temperatures in bakeries and glass factories. Our purpose was to investigate the mechanisms involved in heat damage in such work-places on the eye lens.
Methods: :
Bovine lenses were placed in specially designed culture containers for incubation of 2, 8, 11 and 14 days. 160 lenses were used in the study, 20 lenses for each treatment and 20 lenses for each control. Lenses were exposed to 39.5ºC or 37.8ºC by simulating the heat reaching the eye lens in a neighborhood bakery (39.5ºC) and glass factory (37.8ºC). Lens epithelial samples were analyzed for ATPase activities.
Results: :
Intact lenses exposed daily in culture conditions to 37.8ºC for 75min show an increase in lens epithelial cell volume and an increase in ATPase activities. Lenses exposed to 39.5ºC for 60min, 120min a day for 2 days, 120min a day for 3 days show damage to lens epithelial cells and a reduction in ATPase activities.
Conclusions: :
Our results indicate that heat-induced lens damage is dependent on the temperature and length of exposure. Lenses exposed to 37.8ºC as in the glass factory responded to the stress by increasing ATPase activities. Lenses exposed to 39.5ºC responded by a reduction in ATPase activities. The damage was greater when the exposure time was longer.
Keywords: cataract • enzymes/enzyme inhibitors • NaK ATPase