Simple Somatic Cell Assay to Screen Mammalian Embryo Toxicity Caused by Mineral Oil

The success of in vitro fertilization (IVF), mammalian embryo culture and somatic cell nuclear transfer (SCNT) depend on stringent laboratory conditions and quality of chemicals, plastic ware, and glassware used to culture generated embryos. Therefore, all components and conditions need to be regularly monitored to avoid any kind of contamination and toxicity. Mineral oil (MO), a petroleum product, is extensively used to overlay the embryo cultures to maintain pH and osmolality of the culture medium. In human and farm animals, embryos are cultured with MO for 5 to 7 days to develop fertilized embryos to blastocyst stage 1 . Commercial suppliers claimed that MO is embryo safe by testing it with mouse embryo culture; however, MO quality can varied by a lot number and may deteriorate by improper storage and transport conditions. In addition, MO is an oil product that makes it susceptible to peroxidation and free radical formation 2,3 . Therefore, embryologist( s) should be more attentive to avoid MO-based embryo contamination and toxicity.