Evaluation of Collagen Fibers, MMP2, MMP9, 8-OHdG and Apoptosis in the Aorta of Ovariectomized LDL Knockout Mice Submitted to Aerobic Exercise / Avaliação de Fibras de Colágeno, MMP2, MMP9, 8-OH-Dg e Apoptose na Aorta de Ratas LDL Nocaute Ovariectomizadas Submetidas a Exercício Aeróbico

Abstract Background: In menopause, there is greater cellular exposure to oxidative stress, related to the decreased antioxidative effects of estrogen. These metabolic changes favor the progression of cardiovascular diseases, such as atherosclerosis. Abnormal function of the aorta - the most important artery - is associated with many cardiovascular diseases. Collagen, especially types I and III, is one of the most important aortic wall components and it can be affected by many factors, including menopause. The 8-OHdG is one of the main markers of DNA oxidative damage induced by reactive oxygen species (ROS). Objective: We aimed to investigate effects of moderate aerobic training on the ascending aorta of LDL-knockout (LDL-KO) and ovariectomized female mice. Methods: A total of 15 C57BL/6 mice and 15 LDL-KO mice were divided into experimental groups. The thickness and volume density of types I and III collagen fibers were performed by morphoquantitative analysis, whereas the MMP-2 and MMP-9 and 8-OHdG were detected by immunohistochemistry and apoptosis was detected by the TUNEL assay. The significance level for all tests was p < 0.05. Results: Exercise causes an increase in the thickness of the aorta in LDL-KO groups, particularly accentuated in the ovariectomized groups. The type I collagen fibers showed an increase in volume density influenced by training in both Control groups and in the LDL-KO group. Type III collagen density decreased in both groups. The MMP-2 showed moderade immunostaining in the tunica media in LDL-KO groups, which did not occur in the control groups and the MMP-9 stained irregularly in all tissues. The marker 8-OhdG was stronger in the exercise training groups. Additionally, the ovariectomy, the exercise training and the LDL-KO treatments increased apoptosis. Conclusion: These results suggest that moderate-intensity aerobic exercise in ovariectomized mice associated to an increase in LDL rate possibly increases oxidative stress and apoptosis induction.

Resumo Fundamento: Na menopausa, há maior exposição celular ao estresse oxidativo, relacionada à diminuição dos efeitos antioxidantes do estrogênio. Essas alterações metabólicas favorecem a progressão das doenças cardiovasculares, como a aterosclerose. A função anormal da aorta - a artéria mais importante - está associada a muitas doenças cardiovasculares. O colágeno, especialmente os tipos I e III, é um dos mais importantes componentes da parede da aorta e pode ser afetado por muitos fatores, incluindo a menopausa. Por sua vez, 8-OHdG é um dos principais marcadores de danos oxidativos do DNA induzidos por espécies reativas de oxigênio (EROS). Objetivo: Investigar os efeitos do treinamento aeróbico moderado na aorta ascendente de camundongos fêmeas, nocaute para LDL (LDL-KO) e ovariectomizadas. Métodos: Um total de 15 animais C57BL/6 e 15 animais LDL-KO foram divididos em grupos experimentais. A espessura e a densidade de volume das fibras de colágeno tipos I e III foram realizadas por análise morfoquantitativa; MMP-2 e MMP-9 e 8-OHdG foram detectadas por imunohistoquímica; e a apoptose foi detectada pelo ensaio TUNEL. O nível de significância adotado para todos os testes realizados foi p < 0,05. Resultados: o exercício causa aumento da espessura da aorta em grupos LDL-KO, particularmente acentuada em grupos ovariectomizados. As fibras de colágeno de tipo I mostraram aumento da densidade de volume influenciado pelo treinamento em animais controle e LDL-KO. A densidade do colágeno tipo III diminuiu em ambos os grupos. A MMP-2 mostrou imunomarcação moderada na túnica média em animais LDL-KO; em grupos controle, a MMP-9 marcou irregularmente em todos os tecidos. O marcador 8-OHdG foi mais forte nos grupos de treinamento de exercícios. Além disso, a ovariectomia, o treinamento físico e os tratamentos de LDL-KO aumentaram a apoptose. Conclusão: Esses resultados sugerem que exercícios aeróbicos de intensidade moderada em camundongos ovariectomizados associados ao aumento da taxa de LDL, possivelmente, aumentam o estresse oxidativo e a indução da apoptose.

Evaluation of Collagen Fibers, MMP2, MMP9, 8-OHdG and Apoptosis in the Aorta of Ovariectomized LDL Knockout Mice Submitted to Aerobic Exercise.

BACKGROUND: In menopause, there is greater cellular exposure to oxidative stress, related to the decreased antioxidative effects of estrogen. These metabolic changes favor the progression of cardiovascular diseases, such as atherosclerosis. Abnormal function of the aorta - the most important artery - is associated with many cardiovascular diseases. Collagen, especially types I and III, is one of the most important aortic wall components and it can be affected by many factors, including menopause. The 8-OHdG is one of the main markers of DNA oxidative damage induced by reactive oxygen species (ROS). OBJECTIVE: We aimed to investigate effects of moderate aerobic training on the ascending aorta of LDL-knockout (LDL-KO) and ovariectomized female mice. METHODS: A total of 15 C57BL/6 mice and 15 LDL-KO mice were divided into experimental groups. The thickness and volume density of types I and III collagen fibers were performed by morphoquantitative analysis, whereas the MMP-2 and MMP-9 and 8-OHdG were detected by immunohistochemistry and apoptosis was detected by the TUNEL assay. The significance level for all tests was p < 0.05. RESULTS: Exercise causes an increase in the thickness of the aorta in LDL-KO groups, particularly accentuated in the ovariectomized groups. The type I collagen fibers showed an increase in volume density influenced by training in both Control groups and in the LDL-KO group. Type III collagen density decreased in both groups. The MMP-2 showed moderade immunostaining in the tunica media in LDL-KO groups, which did not occur in the control groups and the MMP-9 stained irregularly in all tissues. The marker 8-OhdG was stronger in the exercise training groups. Additionally, the ovariectomy, the exercise training and the LDL-KO treatments increased apoptosis. CONCLUSION: These results suggest that moderate-intensity aerobic exercise in ovariectomized mice associated to an increase in LDL rate possibly increases oxidative stress and apoptosis induction.

Effect of different exercise intensities on the pancreas of animals with metabolic syndrome

Metabolic syndrome (MS) comprises several metabolic disorders that are risk factors for cardiovascular disease and has its source connected to the accumulation of visceral adipose tissue (VAT) and development of insulin resistance. Despite studies showing beneficial results of exercise on several risk factors for cardiovascular disease, studies evaluating the effects of different intensities of exercise training on the pancreas with experimental models are scarce.Methods: In total, 20 Wistar rats were used, divided into four groups: control (C), metabolic syndrome (MS and without exercise), metabolic syndrome and practice of walking (MSWalk), and metabolic syndrome and practice of running (MSRun). The applied procedures were induction of MS by fructose in drinking water; experimental protocol of walking and running; weighing of body mass and VAT; sacrifice of animals with blood collection and removal of organs and processing of samples for light microscopy using the analysis of volume densities (Vv) of the studied structures.Results: Running showed a reduction of VAT weight (–54%), triglyceride levels (–40%), Vv[islet] (–62%), Vv[islet.cells] (–22%), Vv[islet.insterstitial] (–44%), and Vv[acinar.insterstitial] (–24%) and an increase of Vv[acini] (+21%) and Vv[acinar.cells] (+22%). Regarding walking, we observed a decrease of VAT weight (–34%) and triglyceride levels (–27%), an increase of Vv[islet.cells] (+72%) and Vv[acinar.cells] (+7%), and a decrease of Vv[acini] (–4%) and Vv[acinar.insterstitial] (–16%) when compared with those in the MS group.Conclusion: Our results suggest that the experimental model with low-intensity exercise (walking) seems to be more particularly recommended for preventing morphological and metabolic disorders occurring in the MS.