Do you have any suggestions to extract RNA from frozen blood samples collected from mice, for miRNA studies? The blood samples were stored in Eppendorf tubes at -80C.
You will use the blood RNA extraction kit, such as 1154G84 Quick-RNA Whole Blood Kit (50 Preps), however RNA degrades quite quickly even in -80 so if your samples several weeks old it is quite likely that you will extract highly degraded RNA.
For miRNA studies you are fine with just extracting RNA with a kit that is specific for blood, for example Zymo (https://www.zymoresearch.com/products/quick-rna-whole-blood). If your samples have been at -80C you should have no problems, we have done that many times.