The overall success of any embryology laboratory depends on its ability to maintain consistency from week to week. Quality control practices not only minimize variation within an experiment and increase cost effectiveness, but also make running the lab easier from day to day. From the media and oil overlay to the quality of culture ware, many factors impact the success of a laboratory. By screening contact supplies before they are used in an experiment, an additional variable may be removed. One way of screening contact supplies is to use a 1-cell mouse embryo assay (MEA). The aim of this study was to first identify a quality source of oil overlay and then examine the quality of plastic ware over the course of one year in an attempt to identify variables that are most often toxic to embryos. One-cell mouse embryos (C57BL/6 � CBA/Ca) were used to screen 10 lots of oil from 5 suppliers (n = 70 embryos per oil over 7 replicates). After safe oil was identified, contact supplies including filters, dishes, tubes, and bottles were tested (n = 30 embryos per assay over 3 replicates). Supplies were first soaked with a simple medium lacking amino acids, EDTA, and protein. The duration of medium exposure to contact supplies was the same as their intended use, i.e. bottles stored media for a week before testing. This medium was then used to make culture drops under safe oil. Embryos were grown for 5 days in the simple medium, and development was assessed at 78 and 96 h. Embryos that reached 50% early blastocyst development on Day 4 and 80% expanded blastocyst development on Day 5 were stained and total cell numbers assessed. Items whose embryos did not reach the developmental cut-off values on Day 4 or 5 failed the assay. Blastocyst cell numbers were compared to a known control, and those items that were significantly different failed the assay. Five out of 10 lots of oil failed; four of the lots were from the same supplier. In this assay, such oils failed each replicate. Of 94 contact supplies, 17 (18%) failed the MEA. There was no pattern for products that failed more often than another, i.e. filters did not fail more often than dishes or bottles. However, a general trend was identified for one supplier of oil, as this source appeared to have more toxic lots than those of other suppliers. Using a safe oil source is first priority in an embryology laboratory. There appears to be no way to predict toxicity of plastic ware, so all contact supplies must be either screened before use or introduced into a laboratory one at a time. General record keeping of lot numbers should make it easier to pinpoint potential problems with toxic plastic ware when they arise. The impact of this study is that without quality control in a laboratory, research studies can be compromised.
This work was supported by Vitrolife.