For that purpose, 21 - to 23 - month - old mice were treated with daily injections of either recombinant GDF11 (rGDF11, 0.1 mg / kg mouse body weight), a dosing regimen that increases GDF11 levels in old mice toward youthful levels (13), or phosphate - buffered saline (PBS)(vehicle) for 4 weeks, and their blood vessels were subsequently analyzed by using the volumetric assay described above. (scienceintheclassroom.org)
Before long, they could render an entire mouse body transparent in two weeks. (scientificamerican.com)