Improvement in cardiac function of ovariectomized rats by antioxidant tempol

Tempol Preserves Endothelial Progenitor Cells in Male Mice with Ambient Fine Particulate Matter Exposure

Ambient fine particulate matter (PM) exposure associates with an increased risk of cardiovascular diseases (CVDs). Major sex differences between males and females exist in epidemiology, pathophysiology, and outcome of CVDs. Endothelial progenitor cells (EPCs) play a vital role in the development and progression of CVDs. PM exposure-induced reduction of EPCs is observed in male, not female, mice with increased reactive oxygen species (ROS) production and oxidative stress. The lung is considered an important source of ROS in mice with PM exposure. The aim of the present study was to investigate the sex differences in pulmonary superoxide dismutase (SOD) expression and ROS production, and to test the effect of SOD mimic Tempol on the populations of EPCs in mice with PM exposure. Both male and female C57BL/6 mice (8–10 weeks) were exposed to intranasal PM or vehicle for 6 weeks. Flow cytometry analysis demonstrated that PM exposure significantly decreased the levels of EPCs (CD34⁺/CD133⁺) in both blood and bone marrow with increased ROS production in males, but not in females. ELISA analysis showed higher levels of serum IL-6 and IL-1βin males than in females. Pulmonary expression of the antioxidant enzyme SOD1 was significantly decreased in males after PM exposure, but not in females. Administration of the SOD mimic Tempol in male mice with PM exposure attenuated the production of ROS and inflammatory cytokines, and preserved EPC levels. These data indicated that PM exposure-induced reduction of EPC population in male mice may be due to decreased expression of pulmonary SOD1 in male mice.

The effects of estrogen deficiency and aging on myocardial deformation and motion in normotensive female rats

OBJECTIVE

Estrogen deficiency is associated with left ventricular (LV) dysfunction in postmenopausal women and ovariectomized rats. Whether the relationship between estrogen deficiency and LV dysfunction is independent of cardiovascular disease (CVD) risk factors remains uncertain. This study assessed the effects of short-term and long-term estrogen deficiency on cardiac structure and function using conventional and speckle tracking echocardiography, independent of traditional CVD risk factors.

METHODS

Female Sprague-Dawley rats were divided into short-term (6 wks) ovariectomized (n = 9), short-term sham-operated (n = 10), long-term (6 mo) ovariectomized (n = 8), and long-term sham-operated (n = 9) groups. Cardiac geometry, systolic and diastolic function, and myocardial deformation and motion were measured using echocardiography.

RESULTS

Ovariectomy had no effect on conventional echocardiography measures of cardiac structure or function. Compared with short-term, long-term groups had reduced LV internal diameter (false discovery rate [FDR] adjusted P = 0.05) and impaired relaxation (e'; FDR adjusted P = 0.0005) independent of body mass and blood pressure (BP). Global longitudinal strain was impaired in ovariectomized compared with sham-operated rats (FDR adjusted P = 0.05), but not after adjusting for body mass and BP (FDR adjusted P = 0.16). Global longitudinal strain (FDR adjusted P = 0.05), strain rate (FDR adjusted P = 0.002), and velocity (FDR adjusted P = 0.04) were impaired in long-term compared with short-term groups. Global longitudinal strain rate remained impaired after adjustments for body mass and BP (FDR adjusted P = 0.02).

CONCLUSIONS

Estrogen deficiency does not independently cause cardiac remodeling, LV dysfunction, or impaired myocardial deformation. Traditional CVD risk factors accompanying estrogen deficiency may account for cardiac remodeling and dysfunction observed in postmenopausal women.

Beneficial Effect of Tempol, a Membrane-Permeable Radical Scavenger, on Inflammation and Osteoarthritis in In Vitro Models

Osteoarthritis (OA) is one of the most common and widespread diseases which is highly disabling for humans. This makes OA a chronic disease for which it is urgent to find new therapeutic strategies. The inflammatory state in OA contributes to its progression through multiple mechanisms involving the recruitment of phagocytes and leukocytes, inflammatory response, and reactive oxygen species (ROS) production. Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) is classifiable as a piperidine nitroxide, with excellent antioxidant effects, while its anti-inflammatory role is not yet clear. On this basis, we explored its promising biological properties in two in vitro model:, macrophage (J774) and chondrocyte (CC) cell lines. With this aim in mind, we induced inflammation in J774 and CC using lipopolysaccharide (LPS) and Interleukin1β (IL-1β), and after 24, 72 and 168 h of tempol treatment analyzed their effects on cytotoxicity and anti-inflammatory activity. Our data suggested that tempol treatment is able to reduce inflammation and nitrite production in LPS-induced J774 as well as reducing the production of proinflammatory mediators including cytokines, enzymes, and metalloproteases (MMPs) in IL-1β-stimulated CC. Thus, since inflammation and oxidative stress have a crucial role in the pathogenesis and progression of OA, tempol could be considered as a new therapeutic approach for this pathology.