Proinflammatory Role of Angiotensin II in the Aorta of Normotensive Mice

Figure 1. Hemodynamic evaluation showing mean values for dyastolic, systolic, and mean arterial pressure, as well as heart rate. The subpressor dose of angiotensin II did not change any of the evaluated parameters. N=7/group.

Figure 2. Immunostaining for inflammatory markers in aorta of mice. Positive staining for IL1-β increased in earlier period (30 minutes) in tunica adventitia and perivascular adipose tissue (PVAT) and in a long period (48 hours) in tunica media, tunica adventitia, and PVAT after angiotensin II injection. Angiotensin II increased immunostaining for TGF-β in acute and late periods in tunica media and later in tunica adventitia. iNOS immunostaining increased in adventitia 48 hours after Ang II injection, while in PVAT increased earlier, after 30 minutes. N=7/group. ∗≤0.05; ∗∗≤0.01; ∗∗∗≤0.001 compared to control.

Figure 3. Photomicrography showing immunostaining for IL1-β in aorta of mice. Positive staining for IL1-β (arrows) increased in earlier period (30 minutes) in tunica adventitia (TA) and perivascular adipose tissue (PVAT) and in a long period (48 hours) in tunica media (TM), tunica adventitia and PVAT after angiotensin II injection (Magnification: 40x).

Figure 4. Photomicrography showing immunostaining for TGF-β in aorta of mice. Angiotensin II increased immunostaining for TGF-β (arrows) in acute and late periods in tunica media and later in tunica adventitia (Magnification: 40x).

Figure 5. Photomicrography showing immunostaining for iNOS in aorta of mice. iNOS immunostaining (arrows) increased in adventitia 48 hours after Ang II injection, while in PVAT increased earlier, after 30 minutes (Magnification: 40x).

Figure 6. Macrophage counting in aorta of mice. The subpressor dose of angiotensin II (30ng/kg) was able to induce acute macrophage migration, after 30min in perivascular adipose tissue. The injection of angiotensin II was also able to increase macrophage density in adventitia in two different moments after 1 hour and 24 hours. N=7/group. ∗≤0.05 compared to control.

Figure 7. Photomicrography showing immunostaining for CD45 in aorta of mice. The subpressor dose of angiotensin II (30ng/kg) was able to induce acute macrophage migration (arrow), after 30min in perivascular adipose tissue (PVAT). The injection of angiotensin II was also able to increase macrophage density in tunica adventitia (TA) in two different moments after 1 hour and 24 hours (Magnification: 40x).

Figure 8. Immunostaining for α-actin to study contractile phenotype of vascular smooth muscle cells in tunica media. The analysis showed a slight reduction (not significant) of positive staining in mice injected with angiotensin II, after 48 hours. N=7/group.

Figure 9. Photomicrography showing immunostaining for α-actin to study contractile phenotype of vascular smooth muscle cells in tunica media. There was a slight reduction (not significant) of positive staining in mice injected with angiotensin II, after 48 hours (Magnification: 40x).

Figure 10. Proinflammatory responses of angiotensin II in aorta of mice. In the presented scheme, Ang II induces a fast macrophage migration to PVAT, possibly increasing iNOS and IL1-β expression. A secondary macrophage migration to tunica media may be related to a late increase of iNOS and IL1-β expression. On the other hand, TGF-β quickly increases in tunica media. The reason why the late expression of TGF-β in adventitia and PVAT could be influenced by earlier TGF-β expression or by macrophages infiltration needs to be investigated.