Muscle Injury Models in Transgenic Mice

Hindlimb muscles of Acvr1^tnR206H/+; R26^NG/+;Tie2-Cre mice were injured either by pinch injury or cardiotoxin injection. For pinch injury, a force of approximately 3800–4000× g was applied to the mid-belly of the gastrocnemius (GA) muscle using a Randall Selitto Paw Pressure Test Apparatus (IITC Life Science, Woodland Hills, CA, USA) while the mice were under isoflurane anesthesia, as described [30 (link)]. A separate cohort of Acvr1^tnR206H/+; R26^NG/+;Tie2-Cre mice was injured by injection of 50 μL of 10 μM cardiotoxin (Latoxan, #L8102-1MG; Portes-lès-Valence, France) in sterile 1X Dulbecco’s phosphate-buffered saline (PBS; Gibco; Grand Island, NY, USA) into the tibialis anterior (TA) muscle. To induce muscle injury in Acvr1^{FLEx(R206H)/+};CAG-Cre^ERT2 mice, 100 μL of 10 μM cardiotoxin (Sigma-Aldrich, #C9759) was injected into the GA muscle.