AMELIORATION OF UV-B DAMAGE UNDER HIGH IRRADIANCE. II: ROLE OF BLUE LIGHT PHOTORECEPTORS

Abstract Background Cataracts have been verified to be associated with a number of risk factors. The sun and artificial light sources, including light-emitting diode (LED) and fluorescent light tubes, are the primary sources of short-wavelength blue light. With the increasing popularity of blue-rich LED-backlit display devices, our eyes are now exposed to more short-wavelength blue light than they were in the past. The goal of this study was to evaluate the role of short-wavelength blue light in the formation of cataract. Additionally, the pathogenesis of cataracts after short-wavelength light exposure was investigated.Methods SD rats were randomly divided into 2 main groups: a control group (10 rats each for the 4-, 8-, and 12-week groups) and an experimental group (10 rats each for the 4-, 8-, and 12-week groups). The rats in the experimental group were exposed to a short-wavelength blue LED lamp for 12 hours per day. After exposure to the blue LED lamp, the rats were maintained in total darkness for 12 hours, after which a 12-hour light/dark cycle was resumed. The intensity of the lamp was 3000 lux. At the end of the short-wavelength blue LED lamp exposure (for 4, 8, and 12 weeks), the expression levels of caspase-1, caspase-11 and gasdermin D (GSDMD) in rat epithelium cells (LECs) were examined in rat epithelial cells (LECs) using qRT-PCR and Western blotting analyses. Results After 6 weeks, cataracts had developed in the experimental rats (4/20 eyes). The clarity of the lens then gradually worsened with the duration of exposure. Twelve weeks later, all of the rat eyes had developed cataracts. Then the expression levels of caspase-1, caspase-11 and GSDMD at 4, 8, and 12 weeks were significantly higher in samples from rats exposed to a short-wavelength blue LED lamp than samples from control rat (p˂0.05). Conclusion The data indicate that pyroptosis play a key role of in cataracts induced by short-wavelength blue light exposure, highlighting caspase-1, caspase-11 and GSDMD as possible therapeutic targets for cataract treatment. This study might provide new insight into the novel pathogenesis of cataracts.

Download Full-text

Cryptochrome 2 is involved in betacyanin decomposition induced by blue light in Suaeda salsa

Functional Plant Biology ◽

10.1071/fp06073 ◽

2006 ◽

Vol 33 (7) ◽

pp. 697 ◽

Cited By ~ 6

Author(s):

Wang Chang-Quan ◽

Liu Tao

Keyword(s):

Western Blot ◽

Blue Light ◽

Hypocotyl Elongation ◽

Suaeda Salsa ◽

Biosynthesis Pathway ◽

Tyrosine Hydroxylation ◽

Key Enzyme ◽

Cryptochrome 2 ◽

Hydroxylation Activity

Seeds of the halophyte Suaeda salsa (L.) Pall. were cultured in 24 h dark and 14 h blue light / 10 h dark to examine the role of blue light and the blue-light-absorbing photoreceptor cryptochrome 2 (CRY2) in betacyanin accumulation, hypocotyl elongation and cotyledon opening in S. salsa seedlings. Darkness significantly promoted betacyanin accumulation and hypocotyl elongation but inhibited cotyledon opening. Blue light suppressed betacyanin accumulation and hypocotyl elongation but stimulated cotyledon opening. Betacyanin in S. salsa seedlings decomposed with time in blue light. Western blot analysis showed that CRY2 protein accumulated both in hypocotyls and cotyledons of S. salsa seedlings grown in dark, but degraded with time in blue light, which was paralleled by a decrease of tyrosine hydroxylation activity of tyrosinase, a key enzyme involved in the betalain biosynthesis pathway. These results suggest that CRY2 protein mediates betacyanin decomposition via inactivation of tyrosinase in S. salsa seedlings, and the blue-light-dependent degradation of CRY2 protein is crucial to its function.

Download Full-text