Progesterone and glucocorticoids-dependent mechanisms in photoreceptor protection

SUBURO AM; CUBILLA MA; MARQUIONI MD; BERMUDEZ V

Simposio; XV International Symposium on Retinal Degeneration RD2012; 2012

Progesterone and glucocorticoids-dependent mechanisms in photoreceptor protection Suburo, Angela M.; Cubilla, Marisa A; Melisa D. Marquioni; Bermúdez, Vicente. Purpose. Glucocorticoids (GCs) are excellent protectants for light-stressed photoreceptors. However, there is little information about the effects of progesterone (PRG). Therefore, we compared the effects of these steroids on photoreceptor survival after exposure to a light-stressful environment. Material and Methods. We used Balb-c male mice, cared in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. They were exposed to 1,500 lux for 2 or 4 days. Mice received saline, DEX or PRG (1 or 4 mg/kg/day, sc). Outer nuclear layer (ONL) damage was studied in cryosections after TUNEL reaction or Neutral Red staining. Rhodopsin (RHO), Bcl-XL, Bcl2 and cleaved caspase-3 (CC-3) were evaluated by Western blots. Results. Control mice showed numerous TUNEL+ nuclei at 2 days, and extensive ONL damage after 4 days. Light exposure decreased RHO and Bcl-XL, but was accompanied by an increase of Bcl2 and CC-3. Only minimal damage of the ONL appeared after DEX or PRG treatment. In addition, both steroids prevented the decreases of RHO and Bcl-XL and the increases of Bcl2 and CC-3. Conclusions. Low doses of DEX or PRG were almost equally effective in preventing retinal damage induced by light exposure. Results suggest that both glucocorticoid and progesterone receptors might be involved in photoreceptor survival.