Abstract
Purpose:
Components of the herb rosemary (Rosemarinus officinalis) are known to possess antioxidant properties. We have undertaken a study of these effects and their efficacy in reducing or preventing oxidative damage done to the retina during acute light damage by examining the effects of rosemary treatment on retinal gene expression in the presence and absence of intense light mediated damage.
Methods:
Dark-reared male Sprague-Dawley rats were either (a) injected with rosemary extract or a vehicle solution, treated with 24 hours of green light challenge followed by a 24 hour light recovery, or (b) injected with a rosemary extract and maintained under normal conditions for zero, 1 or 5 hours post-injection. Subjects were then euthanized and retinas excised and snap frozen. RNA was extracted using a Trizol/Qiagen RNEeasy extraction method and subjected to Agilent NanoDrop analysis to ensure high RNA integrity. RNA was then assayed on Affymetrix Rat Gene 1.0 ST microarrays, and the resulting data were analyzed using R and BioConductor.
Results:
Comparing rosemary treated, non-light damaged retina to untreated controls, we see a modest decrease in expression of Hspa family genes, homologous to HSP70 in humans. A decreased level of Hspa family expression in this study may suggest a lower turnover of Hspa proteins. Similarly, many members of the crystallin family saw a slight decrease in expression level, possibly implicating a similar activity by rosemary's antioxidant components on crystallin proteins. In our light damage rosemary treated versus vehicle treated studies, most Hspa family genes do not exhibit a marked change in gene expression, tending towards slightly higher in the rosemary treated retinas. Conversely most crystallin family genes show a steep increase in expression in vehicle treated light damaged retinas, with crystallin expression levels remaining comparatively lower in the rosemary treated retinas.
Conclusions:
We believe that our initial findings support the notion that rosemary's antioxidant components may confer a resistance to oxidative damage by protecting oxidation response proteins from initial damage. We believe this produces a protective context that either slows or mitigates initial oxidative damage, and that more detailed investigation of rosemary's mode of action on retinal gene expression warrants consideration.
Keywords: 533 gene/expression •
634 oxidation/oxidative or free radical damage