Figure 2.

Fractionated irradiation causes activation of caspases in human lung endothelial cells, which is attenuated by lovastatin. Human microvascular endothelial cells of the lung (HMVEC-L) were seeded in high density and grown to confluency before lovastatin (Lova) (5 μM) pretreatment. After incubation period of 24 h, lovastatin concentration was reduced (1 μM) and irradiation was performed (4x4 Gy) as described in methods. Control cells were vehicle-treated and subjected to sham irradiation. (a) Protein extracts were harvested 24 h after the last irradiation and analyzed for the expression of pro-caspase 3 (Casp. 3), cleaved caspase 3 (cl. Casp. 3), cleaved caspase 7 (cl. Casp. 7), Poly(ADP-ribose)-polymerase 1 (PARP-1) as well as of Bax, Bcl-2 and XIAP. Expression of β-actin was used as loading control. (b) mRNA levels of Bax, Bcl-2, Bid, caspases 3 (Casp3) and 7 (Casp7) as well as of Fas ligand (FasL) and Fas receptor (FasR) were analyzed six hours after the last irradiation using quantitative real-time PCR. Results are shown as mean±S.D. of a representative experiment performed in triplicates. mRNA expression of ≥2 and ≤0.5 as compared with control (set to 1.0) are marked with dashed lines. n.d., not detectable