Abstract

2-Bromopropane (2-BP), a cleaning agent, is used as an alternative to ozone-depleting solvents. Previously, 2-BP was shown to have cytotoxic effects on mouse blastocysts and is associated with defects in their subsequent development, both in vitro and in vivo. In addition, it was found that 2-BP also has cytotoxic effects on oocyte maturation and subsequent pre- and post implantation development in vitroand in vivo, and significantly reduces the rate of oocyte maturation, fertilization, and embryonic development in vitro. This study shows that 2-BP (5 to 10 μM) induces apoptotic processes in mouse embryonic stem cells (ESC-B5), but exerts no effects at treatment dosages below 5 μM. In ESC-B5 cells, 2-BP directly increased the content of reactive oxygen species (ROS), significantly increased the cytoplasmic free calcium and nitric oxide (NO) levels, triggered a loss of mitochondrial membrane potential (MMP), activated caspases-9 and -3, and induced cell death. Pre-treatment with NO scavengers suppressed the apoptotic biochemical changes induced by 10 μM 2-BP and promoted the gene expression levels of p53 and p21, which are involved in apoptotic signaling. These results demonstrate for the first time that 2-BP triggers apoptosis in mouse embryonic stem cells via ROS, NO and the activation of mitochondria-dependent cell death signaling.

Key words: 2-Bromopropane, apoptosis, oxidative stress, calcium, nitric oxide.