Effects of lycium barbarum polysaccharide on retinal morphometry and function of retinal photic injury in rats / 眼科

Objective To investigate the functional protective effect of lycium barbarum polysaccharide (LBP) against light-in-duced retinal degeneration. Design experimental studies. Participants sixty SD rats were divided randomly into 6 groups. Methods Sprague-Dawley rats were exposed for 24 hours to 2000-lux cool white fluorescent light after treatment with LBP. Scotopic flash elec-troretinogram (ERG) were recorded before and on day D1, D6 and D14 after light exposure. The b-wave amplitude was statistic. In addi-tion, rats from each group were killed for retinal morphometric analyses. Main outcome Measure The amplitudes of b-wave of scotopic flash ERG, the histopathological changes. Results In the untreated group, light exposure caused collapse of the b-wave sensitivity curves. Bmax was reduced by 29.97% at D1 without subsequent recovery. Histopathology of the temporal superior central retinas of rats showed outer segment disorganization and shortening, the inner segments swelled and vacuolated, the outer nuclear layer thicknesses decreased markedly with subsequent recovery. In the treated groups, light exposure had a weaker effect on sensitivity curves. The values of b-wave amplitude were significantly increased than those in the exposed-untreated group (P=0.005). Retinal morphometry was pre-served. Conclusion LBP afford functional protection against light-induced retinal damage. (Ophthalmol CHN, 2009, 18: 229-233)

Protective Effect of Heat Shock Proteins 70.1 and 70.3 on Retinal Photic Injury after Systemic Hyperthermia

PURPOSE: This study aimed to determine the relationship between the heat shock protein 70 from hsps70.1 and 70.3 on retinal photic injury after systemic hyperthermia. METHODS: Eight-week-old female C57BL/6 mice were kept at a constant temperature of 41~42 degrees C for 25~30 minutes. After dark-adaptation for 8 hours, intense light of 11000 lux was maintained for 6 hours. Histology and immunohistochemistry for the inducible heat shock protein 70 (hsp70), the constitutive heat shock protein 70 (hsc70), and western blot analysis, reverse transcriptase-polymerase chain reaction for hsp70.1 and hsp70.3 were performed just before photic injury and after 1, 4, 7, and 14 days. RESULTS: Light-induced retinal degeneration was prevented by thermotolerance. After hyperthermia, hsp70 was densely expressed in the inner segment of the photoreceptor layer on the photic injury. Hsp70 expression increased for 4 days after photic injury and slowly decreased thereafter. mRNA from hsp70.3 was induced earlier than that of hsp70.1. CONCLUSIONS: Retinal photic injury was prevented by hyperthermia-induced hsp70. Hsp70 from hsp70.3 may be a rapid and short-lived responder, and that from hsp70.1 is a slower and more sustained responder. Hsp70 from hsp70.3 may be an initial retinal chaperone while hsp70 from hsp70.1 may be a sustained chaperone.

Effect of the Absence of Heat Shock Protein 70.1 (hsp70.1) on Retinal Photic Injury

This study aimed to evaluate the protective effect of heat shock protein70 (hsp70) on retinal photic injuries, and to determine the relationship between hsp70s from hsp70.1 and 70.3. C57BL/6 wild type (hsp70.1+/+) and knockout type (hsp70.1-/-) mice from the same littermates were placed in light of 11000 lux for 6 hours, and were sacrificed at 1, 4, 7, and 14 days after stress. H & E staining, immunohistochemistry, and western blot analysis were performed. The hsp70.1-/- mice exhibited more disarranged and more diffusely destroyed photoreceptors than the hsp70.1+/+ mice. Hsp70 induction by light in both the hsp70.1 +/+ and hsp70.1 -/- mice peaked at 1 day after light stress. The Hsp70 level in the hsp70.1 +/+ mice reduced slowly and was almost constant for 7 days. However, in the hsp70.1 -/- mice, it decreased rapidly and returned, after 7 days, to a similar level to that prior to light exposure. According to which gene they originate from, hsp70s may play specific roles in protecting the retina against stresses. Hsp70 from the hsp70.1 gene may act as a sustained responder to retinal photic injury.