Mechanisms of the first and second window of protection of preischaemic vagal stimulation on myocardial infarction in mice

KELLY, JAZMIN; DIODATI MENDEZ, NAHUEL; MARCHINI, TIMOTEO; FRANCO RIVEROS, VERENA; BERNATENE, EDUARDO; CASANOVA, VERONICA; EVELSON, PABLO; BUCHHOLZ, BRUNO; GELPI, RICARDO

Mar del Plata

Congreso; LXIV Reunión Científica Anual; 2019

Sociedad Argentina de Investigación Clínica

We recently proved that pVS mimicsischaemic preconditioning in having two windows of protection.Our current objective was to further study the mechanisms of theprotective effect of VS during this so-called first and secondwindow. Mice were randomly assigned to different protocols (n=5 - 7 per group). The control group had 30 min of regionalmyocardial ischaemia and 2 h of reperfusion (I/R). The othergroups underwent 10 min of pVS and either 5 min, 3 ? 6 ? 12 ?2 4 ? 48 - 72 or 96 h of recovery between VS and I/R. The 5min, 3 and 72 h groups were redone to receive a muscarinicreceptor inhibitor (atropine). The 5 min and 72 h groups wereperformed yet again to administer a mitochondrial K+ ATPchannel blocker (5-HD) and a nitric oxide synthase inhibitor (LNAME).All groups were catheterised to assess ventricularfunction. Septum (S) and area at risk (AR) samples from the I/R,5 min and 72 h groups were taken to assess mitochondrial activerespiration (MAR), passive respiration (MPR), and the respiratorycontrol ratio (RCR). Hearts were dyed with Evans Blue andincubated in TTC to measure IS. pVS - 5 min had smaller ISwhen compared to I/R (44 ± 3 % and 57 ± 2 %, respectively;p