Mechanisms of the First and Second Window of Protection of Preischaemic Vagal Stimulation on Myocardial Infarction in Mice

TIMOTEO MARCHINI; VERÓNICA CASANOVA; RICARDO J. GELPI; NAHUEL MÉNDEZ DIODATI; EDUARDO A. BERNATENÉ; BRUNO BUCHHOLZ; JAZMÍN KELLY; VERENA B FRANCO-RIVEROS; PABLO EVELSON

Mar del Plata.

Congreso; LXIV Reunión Anual de la Sociedad Argentina de Investigación Clínica.; 2019

Sociedad Argentina de Investigación Clínica.

We recently proved that pVS mimics ischaemic preconditioning in having two Windows of protection. Our current objective was to further study the mechanisms of the protective effect of VS during this so-called first and second window. Mice were randomly assigned to different protocols (n=5-7 per group). The control group had 30 min of regional myocardial ischaemia and 2 h of reperfusion (I/R). The other groups underwent 10 min of pVS and either 5 min, 3-6-12-24-48-72 or 96 h of recovery between VS and I/R. The 5 min, 3 and 72 h groups were redone to receive a muscarinic receptor inhibitor (atropine). The 5 min and 72 h groups were performed yet again to administer a mitochondrial K+ ATP channel blocker (5-HD) and a nitric oxide synthase inhibitor (L-NAME). All groups were catheterised to assess ventricular function. Septum (S) and area at risk (AR) samples from the I/R, 5 min and 72 h groups were taken to assess mitochondrial active respiration (MAR), passive respiration (MPR), and the respiratory control ratio (RCR). Hearts were dyed with Evans Blue and incubated in TTC to measure IS. pVS-5min had smaller IS when compared to I/R (44±3% and 57±2%, respectively; p