EFFECTS OF INTENSE EXERCISE IN A MODEL OF SIMPATIC HYPERACTIVITY IN MICE

LUCIANA WILENSKY, PABLO CASSAGLIA, MARÍA CLARA LLAMOSAS, CELESTE BETAZZA, FLORENCIA SOFÍA FONTANA ESTEVEZ, VERÓNICA CASANOVA, MARÍA CARLA GRECO, CELINA MORALES,; GERMÁN GONZÁLEZ

Mar del Plata

Congreso; LXIII Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica. Mar del Plata, Buenos Aires, Noviembre de 2017; 2018

Sociedad Argentina de Investigación Clínica

EFFECTS OF INTENSE EXERCISE IN A MODEL OF SIMPATIC HYPERACTIVITY IN MICEThe aim was study the effect of endurance exercise protocol on myocardial hypertrophy, baseline ventricular function (VF), myocardial reserve (answer to Isoproterenol, ISO), and also structural histological parameters. Two experimental groups were performed, no transgenic (noTG: FVB) and transgenic (TG: Gsα), divided on sedentary (SED) or intense exercise (IE) groups: SEDnoTG, TG+IE (swim 90 minutes/2 twice, 6 days/week, 4 weeks) and SEDTG, TG+IE. Concluded the protocol, animals were anesthetized and catheterized to make ?in vivo? function. Left ventricle was fixed in formalin-buffer to make histological cuts for collagen quantification, capillary density and myocytes area. Baseline VF was conserved in all the groups (noTG as TG), despite the isovolumetric relaxation (t63) that slowed down on the noTG+IE (10±0,3mseg) respect SEDnoTG (8±0,7mseg, p=0,01). Nevertheless, there was a significant decrease in the reponse percentage to ISO on +dP/dt (noTG+EI: 34±9% vs. SEDnoTG: 78±14%, p=0,021), cardiac frequency (noTG+EI: 27±6% y SEDnoTG: 73±7%, p=0,001) and t63 (noTG+EI: -6±4% vs. SEDnoTG: -29,2±6%, p=0,001). In contrast, TG showed no difference in response to ISO in any parameter previously signed. Histologically, if well there was a tendency to increasing, interstitial collagen showed no significant increase in any group, as well as in capillary density. On the other hand, both noTG (SEDnoTG: 254±14 vs. noTG+EI: 471±20μm2, p=0,001) and TG (SEDTG: 354±19 vs. TG+EI: 527±23μm2, p=0,001) showed a significant increment on myocytes area. This work exposes the IE effects in baseline animals normal and with Gsα protein overexpression, generating a specific cardiac sympathetic hyperactivity response, which shows higher baseline values in the contractility. However, both noTG and TG didn´t show an effect due to the IE at rest. In response to ISO, all parameters were observed reduced in noTG mice, while the TG preserved their values. Histologically, both behaved similarly. In conclusion, transgenicity in this model involves a fundamental tool to understand the effects of exercise intensity in animals and its role on the presence of sympathetic hyperactivity.