(A) Consistent with in vitro data shown in Figure 3, Il21r−/− mice showed less STAT3 phosphorylation in ischemic gastrocnemius muscle, but did not show any difference of STAT1, AKT or ERK1/2 phosphorylation 1 day after HLI when compared to ischemic gastrocnemius muscle from the WT mice. (B) In gastrocnemius muscle at day 7 after HLI, l21r KO had a decreased BCL-2/BAX ratio. N=4–5/group, Data = mean ± SEM. WT, wild type. KO, Il21r knockout.