Abstract 17: Preconditioning With Whole Body Periodic Acceleration (pGz) is Neuroprotective in Model of Asphyxial Cardiac Arrest in Rats.
Whole body periodic acceleration (pGz) is a method which moves the body in a repetitive head to foot motion adding pulses to the circulation increasing pulsatile shear stress. pGz is cardioprotective when performed as a preconditioning strategy. The present study was designed to evaluate the effect of pGz on regulatory proteins involved in initiation (Bax) or inhibition of apoptosis (pAkt, Bcl-2, high Bcl-2/Bax ratio) in brains of rats following asphyxial cardiac arrest (ACA). We hypothesized that pretreatment with one hour of pGz in rats undergoing ACA can diminish brain injury by activation of intracellular signaling cascades that increase ratio of Bcl-2/Bax and increase expression of pAkt. These proteins were chosen because they play important role in apoptotic activity in brain. Male rats (320±25 g weight) were anesthetized, tracheally intubated and ventilated with room air, instrumented to measure hemodynamics and randomized to receive 60 min of pGz (pre-pGz) or no treatment (no-pGz) prior to ACA. Asphyxia was induced by paralysis and airway occlusion for 5 min, followed by resuscitation until return of circulation and recovery for 4 hrs. Expression of the above proteins was measured in frontal cortex by immunoblotting. ROC occurred in 60% of no-pGz and in 100% of pre-pGz group. Pre-pGz preconditioning increased the ratio of Bcl-2/Bax compared to no-pGz from 0.62±0.4 to 1.92±0.47, respectively (p=0.001). The latter increase suggests decreased susceptibility to apoptosis. Similarly, pre-pGz increased expression of pAkt compared to no-pGz from 34±21 to 124±43, respectively (p=0.001). Akt is an important anti-apoptotic protein with higher levels associated with increased cell survival. In conclusion, pGz preconditioning in a rat model of ACA, may provide significant protection from apoptotic neuronal injury and therefore be a valuable neuroprotective strategy prior to procedures likely to involve hypoxia/ischemia.
- © 2010 by American Heart Association, Inc.