Environmental temperature and cataract progression in experimental rat cataract models.
OBJECTIVE
To clarify whether or not ambient temperature relates to cataract development or the progression of cataract formation.


METHODS
36 Brown Norway rats were divided into two groups, a high-temperature (35 +/- 2 degrees C, H = high) breeding group and a regular-temperature (24 +/- 2 degrees C, L = low) group. Each group was further divided into an experimentally induced diabetic cataract subgroup (50 mg/kg streptozotocin, DM), an ultraviolet B exposure-induced cataract subgroup (200 mJ/cm2, UV), and a normal control subgroup (C = control). Slit-lamp microscopy and an anterior image analysis system (EAS-1000) were used to evaluate lens changes.


RESULTS
Both the HC and HUV groups in the 35 degrees C conditions showed higher light scattering than that of the 24 degrees C conditions (LC and LUV) 3 weeks after the start of the experiment. Nine weeks after the start of the experiment, all the rats of the UV subgroups (HUV and LUV) developed anterior subcapsular cataract. The temperature did not have much influence on the progression of the UV-B-induced cataract. From 18 days after the start of the experiment, the HC subgroup showed a wider light scattering area than the LC. An increase in abnormal nuclear scattering light in the crystalline lens of group HC was found in 9 weeks after the start of the experiment, and at the end of the experiment (78 weeks later), dense abnormal nuclear light scattering was found including the prenuclear area. In contrast, the HDM group in the 35 degrees C conditions showed slower cataract progression than that of the LDM group at 24 degrees C room temperature.


CONCLUSIONS
Although further experiments are necessary before we can draw any conclusions about temperature and nuclear changes, paying attention to the effects of temperature on the lens is worthwhile.
Kojima
Masami
M
Department of Ophthalmology, Kanazawa Medical University, Kahoku-gun, Ishikawa-ken, Japan. m-kojima@kanazawa-med.ac.jp
Okuno
Tsutomu
T
Miyakoshi
Minoru
M
Sasaki
Kazuyuki
K
Takahashi
Nobuo
N
D000818:Animals; D002386:Cataract / Q000209:etiology* / Q000503:physiopathology*; D003080:Cold Temperature; D003921:Diabetes Mellitus, Experimental / Q000150:complications; D018450:Disease Progression; D006358:Hot Temperature; D007908:Lens, Crystalline / Q000473:pathology / Q000528:radiation effects*; D008027:Light; D008297:Male; D023421:Models, Animal; D051381:Rats; D011914:Rats, Inbred BN; D012542:Scattering, Radiation; D014466:Ultraviolet Rays / Q000009:adverse effects