Hi, I haven't found and explanation for cell viability increase when RAW 264.7 macrophages are stimulated with LPS (compared with RAW 264.7 macrophages with no stimulation of LPS). Regarding this, I've found cell viabilities over 100% percent.
Does anyone have an explanation for this behavior? (if you have a paper to add, I woud be very very thankful). Thank you al!!
Hello,
Apparently there can be interference in MTT assay with activated macrophage cell line.
"Interference in MTT cell viability assay in activated macrophage cell line."
https://www.ncbi.nlm.nih.gov/pubmed/12605874
And also, the question of the viability as been answered in RG in the past
https://www.researchgate.net/post/Why_do_my_MTT_assay_results_sometimes_show_cell_viability_of_more_than_100_or_more_than_the_control
Hope it helped,
Regards
In addition to Mathieu's response above - I'm not particularly familiar with inflammation research, but I believe that LPS can affect mitochondrial activity?
http://www.jbc.org/content/278/42/41510.full
If I recall, a recurrent problem with MTT assays is that it is an approach that is believed to be dependent on mitochondrial conversion of the MTT dye to the formazan product. Therefore MTTs may not be a reliable measure of viability for anything that affects mitochodrial activity (as LPS seems to). Several people I know have switched from MTT/MTS assays to SRB assays to avoid this problem (SRB assays do not depend on mitochondrial activity, and instead measure cellular protein levels).
Have you tried repeating the experiment using another viability measure, even something as crude as say Trypan blue exclusion? This might give an answer if the effect you're seeing is due to LPS affecting the mitochondria, which in turn may alter formazan production rate.
Hope this helps!
- Badges
- Science topic
- Similar topics
- Biological Science
- Microbiology
- Virology
- Virus