Bcl-2, Bax, and c-Fos expression correlates to RPE cell apoptosis induced by UV-light and daunorubicin.

PURPOSE: The aim of this study was to determine the role of Bcl-2, Bcl-X L, Bax, and c-Fos in regulation of apoptosis, induced by ultraviolet-light A (UV-A) and daunorubicin (DNR), in retinal pigment epithelium (RPE) cells grown on bovine extracellular matrix (ECM)-coated or uncoated plastic dishes. METHODS: Apoptosis in confluent RPE cells cultured on ECM-coated or uncoated dishes was induced by UV-A or DNR. Apoptosis was detected by 7-amino-actinomycin D labeling followed by flow cytometry and by terminal deoxy-transferase mediated X-dUTP nick end labeling (TUNEL). Cellular expression of Bcl-2, Bcl-X L, Bax, and c-Fos was determined by the use of antibodies and flow cytometry, Western blot analysis, and immunocytochemical staining. RESULTS: Both UV-A and DNR induce apoptosis in human RPE cells in vitro. Human fetal RPE cells grown on ECM-coated dishes were significantly more resistant to UV-A or DNR induced apoptosis than cells grown on uncoated dishes. RPE cells grown on ECM-coated dishes expressed higher Bcl-2 levels and lower Bax levels compared to cells grown on uncoated dishes. However, Bcl-X L and c-Fos levels were comparable in the two cultures. After UV-A or DNR treatment, Bcl-2, Bcl-X L, Bax, and c-Fos levels were differently regulated in cells grown on ECM-coated dishes compared to cells grown on uncoated dishes. CONCLUSION: A significant protection against apoptosis of RPE cells grown on ECM compared to cells grown on uncoated plastic dishes was found after exposure to UV-A or DNR. This protection was found to be proportionally correlated to the anti-apoptotic protein Bcl-2 and inversely correlated to the expression of Bax. Furthermore a sustained induction and expression of c-Fos was found to correlate to a higher percentage of apoptotic cells of RPE cells grown on plastic. These findings demonstrate that ECM is of great importance for RPE cell survival during noxious stimuli and points out the essential role for a healthy Bruch's Membrane (BM) for RPE survival.

Po-210 and Pb-210 in water and fish from Taboshar uranium mining Pit Lake, Tajikistan.

Polonium-210 in water and (210)Pb and (210)Po in different fish organs from 3 different fish species in Taboshar Pit Lake (n = 13), located in the uranium mining area in Tajikistan, and in Kairakkum Reservoir (reference lake, n = 3), have been determined as part of a Joint project between Norway, Kazakhstan, Kyrgyzstan and Tajikistan. The average activity concentration of (210)Pb and (210)Po in liver, muscle and bone of Carassius auratus was higher than the concentration in similar tissues of C. carpio and Sander lucioperca from the reference site. The accumulation of (210)Po was higher than for (210)Pb, and the accumulation of (210)Po was highest in the liver of C. auratus (3673 ± 434 Bq kg(-1) ww). Although the average activity concentration of (210)Pb in liver and bones of C. auratus from Pit Lake were fairly similar, a huge variation in the liver activity concentrations (25-327 Bq kg(-1) ww) was found. The results confirm direct uptake of unsupported (210)Po into the liver, and that the distributions of (210)Po and (210)Pb in fish organs were different. The BCF (L/kg) for (210)Po in bone, liver and muscle clearly demonstrates high accumulation of (210)Po in C. auratus, especially in the liver. The average BCFs of liver, bone and muscle were >1.4 × 10(5), >2.5 × 10(4) and >1.4 × 10(4), respectively. All fish in the Pit Lake were found to be in the same trophic level, however, a linear correlation between log (210)Po in liver and δ(15)N could indicate biomagnification of (210)Po in liver of C. auratus. In regards to the recommended Annual Limit of Intake (ALI) for (210)Po, the concentration of (210)Po in muscle tissues of C. auratus is alarming, as there is a high probability for the local population at risk to exceed the recommended ALI through consumption of fish from Taboshar Pit Lake.