A recent article by Mary Kay Bates in American Laboratory is the latest to make a case for hypoxic cell culture, citing the difference in oxygen concentrations in the human body vs. the air we breathe, as well as the essential importance of hypoxia in cancer research. Since Ruskinn (now a division of The Baker Company) has been beating this drum for several years, it is great to see this issue gain a higher profile.
Although it is true that one way to provide hypoxic conditions for cell culturing is, as Bates wrote, by using a cell culture incubator, it is really an incomplete solution to the problem of oxygen concentration. Although a tri-gas incubator can provide a hypoxic environment during the incubation period, it does not protect cells from ambient conditions during any procedures that must take place outside the incubator, such as preparation and feeding. This extra exposure to higher levels of concentration negatively impacts cell growth. According to Dr. Nicholas Forsyth, Senior Lecturer in Stem Cell Biology at the Institute for Science & Technology in Medicine at Keele University, a total of only 10 minutes of exposure to ambient oxygen conditions accumulated over a period of several months is all it takes to adversely affect the results of culturing experiments.
Additionally, as Bates also pointed out, oxygen concentration in the media may be well above the hypoxic conditions in the incubator atmosphere, making it clear that a tri gas incubator is not a sufficient control for oxygen concentration.
The best way to culture cells is to start with hypoxic conditions and maintain them throughout the culturing process. To do this, a hypoxia workstation is required. Also known as a hypoxia chamber, this type of “lab-in-a-box” allows the entire cell culture process to be performed in the precise conditions necessary for optimal cell growth. Access to the chamber is only available through glove ports or a pass-through interlock, so there is no disruption to the hypoxic conditions inside. Because a hypoxia workstation also allows you to control temperature and humidity, cells can be incubated inside the chamber. Cultures are never exposed to ambient conditions – not even for a moment.
But what about the media? Bates pointed out that the development of better media is one advancement in cell culturing. We say that the next advancement will be controlling oxygen concentrations in the media with media preconditioning processes.