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. Author manuscript; available in PMC: 2016 May 13.
Published in final edited form as: Arterioscler Thromb Vasc Biol. 2015 Apr 2;35(5):1218–1225. doi: 10.1161/ATVBAHA.115.305476

Figure 1. Interleukin-21 receptor (IL-21R) levels vary greatly between C57BL/6 and BALB/c mice after hindlimb ischemia (HLI).

Figure 1

Figure 1

(A) Three days after HLI, ischemic gastrocnemius muscle from C57BL/6 mice showed upregulation (~39-fold) of Il21r mRNA level compared to non-ischemic gastrocnemius muscle. BALB/c mice also showed Il21r mRNA level upregulation (~1.7-fold) after HLI. However, the fold changes in BALB/c mice were significantly smaller than C57BL/6 mice (p<0.001, n = 5/group). (B) Il21r mRNA level of CD31+ (CD31 is an endothelial cell marker) cell isolated from C57BL/6 mouse hindlimb muscle tissue is significantly up-regulated ~160-fold) 3 days after HLI when compared to endothelial cells from non-ischemic hindlimb. (p<0.001, n = 4~5/group). (C) Immunofluorescence of ischemic and non-ischemic gastrocnemius muscle IL-21R (red), CD31 (green) and merged from WT or Il21r−/− C57BL/6 mice; co-staining of CD31 and IL21R can be visualized in the ischemic muscle from the WT mice. IL-21R was not detected either in muscle tissue from non-ischemic limb or in the ischemic muscle tissue from Il21r−/− mice. (D) FACS analysis in CD31+ cell fraction isolated from IGA and NGA, IL-21R level in CD31 cells showed a significant increase in IGA compared to NGA from C57BL/6 mouse, but did not show statistical difference from BALB/c mouse. IGA indicates ischemic gastrocnemius muscle, NGA indicates non-ischemic gastrocnemius muscle. WT, wild type. KO, Il21r knockout.