Visit two biology laboratories, for cells and embryos

Welcome to the cell biology Lab. In this  Lab we use cell cultures to evaluate   the impact of different chemicals, such as  the plasticizers present in food packaging In a typical cell culture Lab there are various  equipment, such as cell culture hoods, inverted   microscopes, centrifuges and CO2 incubators at  37 degrees where cultured cells are maintained.  Most of the times, we work with cells that live  attached at the bottom of plastic dishes. Cells   are covered with a liquid, called medium,  containing all the necessary nutrients. Before starting an experiment, cell plates are  observed under an inverted microscope to make   sure they are growing well and to confirm the  absence of bacterial and fungal contaminations.

These cells are called pre-adipocytes,  they can become fat cells. We work always under sterile  conditions in a biosafety cabinet   to avoid contamination of our samples. We seed cells in multi-well plates in  order to assign different treatments. We treat cells with the chemicals we are  interested in, adding them to the culture medium. We include also negative controls, that are cells  not treated, and positive controls, cells treated   with something that surely has an effect. Controls  are necessary to be sure about the results. Now the experiment has been set  up and we place again our plates   in the incubator for the necessary time, usually  10 days, changing the medium every 2 or 3 days.

At the end of the experiment,  cells are stained with a substance   that turn into a color. We can use  a red staining specific for lipids;   in this way we can assess the effect of chemicals  on the amount of fat present in the cells. Under the fluorescence microscope we can  observe cells; lipid droplets are visible in red The red staining, thus the  quantity of fat in the cells,   changes following the chemicals  exposure in respect to control. To be more precise, we can measure the amount of   fluorescence emitted by fat  droplets with a fluorimeter.

We repeat the experiments several times,  then the results are entered in an Excel file   from which we can create histograms.  The greater the fluorescence intensity,   the greater the fat accumulation. The differences  are statistically significant. Good job! Now we know that the chemicals we tested are  able to increase fat accumulation in cells.   If the results are confirmed also in animals, we  can conclude that these chemicals are Obesogens.