Ang-1 upregulates SDF-1α and CXCR-4 expression in the ischemic hearts of db/db mouse.

A: Expression of CXCR-4 in db/db mouse hearts subjected to myocardial ischemia at 24 hours. CXCR-4 positive cell (red) and nuclei were stained by DAPI (blue). B: Quantitative analysis showing that the number of CXCR-4⁺ cells was significantly increased in the Ad-Ang-1 treated db/db mice (n = 6) compared to that of Ad-β-gal-treated db/db mice (n = 9). CXCR-4⁺ cells are expressed as the total number per square mm. Sham control (n = 3). All data represent mean ± SD; *p<0.05. ND =  not detected. C: Western blot and densitometric analysis of myocardial CXCR-4 expression showing that overexpression of Ang-1 significantly increased CXCR-4 expression in db/db mice compared to that of Ad-β-gal-treated db/db mice. All data represent mean ± SD (n = 4 mice); *p<0.05. D. Western blot and densitometric analysis of myocardial SDF-1α expression. Overexpression of Ang-1 significantly increased SDF-1α expression in db/db mice compared to that of Ad-β-gal-treated db/db mice. All data represent mean ± SD (n = 4 mice); *p<0.05. E. Co-localization of CD133 with CXCR-4 and CD133 with SDF-1α in db/db mouse infarcted hearts. CD133⁺ cells (green); CXCR-4⁺ or SDF-1α⁺ cells (red) and nuclei were stained by DAPI (blue, 40X). Merged images show that CD133⁺ cells co-localized with both CXCR-4 (upper panel) and SDF-1α (bottom panel) in the Ad-Ang-1 treated db/db mice, but little co-localization was seen in the Ad-β-gal-treated db/db mice. No specific staining was observed in the sham control group.