ABC | Volume 112, Nº2, February 2019

Original Article Maifrino et al Exercise effects on ovariectomized mice Arq Bras Cardiol. 2019; 112(2):180-188 Figure 4 – Photomicrographs of cross-sections of the aorta of mice submitted to immunohistochemical reaction for 8-OHdG. The immunoexpression of 8-OHdG was observed in all investigated groups. The staining was moderate for LDL KO and Control groups, both the S and the OS. However, for the O and T groups, the observed staining was intense. Calibration bar = 100 µm. Figure 5 – Photomicrographs of cross-sections of the ascending aorta of mice submitted to immunohistochemical reaction for MMP-2. Note the presence of MMP-2 immunoexpression in the tunica intima (arrow) and adventitia (arrowhead) in all control groups (S-C, OS-C and OT-C). In general, the MMP-2 immunoexpression in the LDL KO groups was observed in the intima and adventitia layers, as well as in the middle layer of the aorta (*), which did not occur in any animal of the control groups. Calibration bar: 100 µm. the ascending aorta. The LDL groups, in general, showed MMP-2 immunoexpression beyond the tunica intima and adventitia, but also in the tunica media of the aorta (although very slightly), which was not observed in any groups of control animals (Figure 5). The MMP-9 was expressed in all layers of the ascending aorta of all groups; however, the distribution was heterogeneous (Figure 6). Apoptotic cells were distributed in the media-intima layer of the ascending aorta in all studied groups. The comparation of relative frequency showed that Ovariectomy statistically increased apoptosis in +12,6% in the sedentary group (OS-C) and +19% in physical training group (OT-C) when compared to the apoptosis of the sedentary control group (S-C) (Figure 7). Among the knockout groups, apoptosis rates were higher than the respective controls, regardless if the mice were ovariectomized or not. Thus, the knockout sedentary group increased apoptosis frequency in +28,8% when compared with the control group. Ovariectomy and knockout statistically increased the apoptosis in +24,5% in the sedentary (OS‑LDL KO) and +32,3% in the physical training (OT-LDL KO) groups, when compared to the sedentary control group (S-C). No significant change was observed when comparing the knockout sedentary group (S-LDL-KO) to knockout ovariectomy sedentary (OS-LDL KO) or physical training (OT-LDL KO) groups, with decreased apoptosis in -4,3% and improved apoptosis in +3,5%, respectively. However, the relative frequency of ovariectomy, sedentary and 184