Inhibitory effects of vitamin E on UVB-induced apoptosis of chicken embryonic fibroblasts

Apoptosis research has been focused on several model species in the past decades, whereas studies concerned with non-mammalian vertebrate, particularly birds, have rarely been involved. In accord with requirements to expand the biodiversity of apoptotic research, a chicken embryonic fibroblasts model involving UVB (ultraviolet B) as the death stimulus was established through primary explantation and serial passage. Myriads of antioxidants can inhibit UVB-induced apoptosis by virtue of scavenging reactive oxygen species. To improve our understanding of the possible anti-apoptotic effects and mechanisms of Vitamin E against UVB-induced apoptosis in chicken embryonic fibroblasts, cells treated with Vitamin E after UVB irradiation were stained with AO/EB and Fluo-3/AM to visualize chromatin distribution and calcium homoeostasis, respectively. They were also analysed by flow cytometry to detect mitochondrial transmembrane potential, and cell cycle progression and apoptotic rates were recorded. RT-PCR was used to analyse the expression of some apoptosis-related genes. Typical apoptotic events, including cell shrinkage, blebbing and nuclear condensation, occurred after radiation. In the presence of Vitamin E following irradiation, apoptotic cells were reduced. Ca2+ release was temporarily prevented, and cell cycle arrest at S/G2 checkpoint had almost completely reverted to normal. fas decreased, while procaspase-3 remained nearly unchanged with and without Vitamin E, and bcl2/bax ratio was up-regulated, indicating possible anti-apoptotic mechanisms through the mitochondrial pathway. This new investigation of an apoptosis model involving chicken embryonic fibroblasts expands the database of knowledge across a wider spectrum of vertebrate species.