We would like to measure Xbp1 splicing in the livers of our mutant mice to determine ER stress.
We typically fast mice for 5 hours prior to dissection, but will fasting induce splicing of Xbp1? Can we dissect non-fasted mice during the light cycle, or do we need to dissect when the mice are actively eating (dark cycle)?
Thank you in advance,
Steph
It's worth giving a look at some of U.Ozcan's papers, atleast the fasting-refeeding related changes in Xbp1 will be answered straightaway....
Dear Stephanie,
For most experiments involving liver injury, fasting mice prior to the procedure is very straightforward, since it eliminates variability due to food ingestion and different drug absorption.
Some papers described reduced ATP and GSH levels in livers after 20 hours fasting, although no toxicity happened. In this way, no ER stress would be expected in such short fasting period, so your experiment should be ok.
Regardind the second question, I would suggest you to perform the experiment during the day. We observed that mice eat mostly at night, when they are active, thus the fasting also should be performed at that time. If you fast them in the morning you might not have a satisfactory effect.
Good luck!
Pedro