Preconditioning with +Gz acceleration (head-to-foot inertial load) produces neuroprotection against transient focal cerebral ischemia in rats

Ischemic preconditioning is considered to be the most robust endogenous neuroprotectant. However, the conventional ischemic preconditioning protocol is both invasive and impractical to apply. The aim of the present study was to evaluate whether preconditioning with +Gz centrifuge acceleration (head-to-foot inertial load) which could induce brief episodes of sublethal ischemia in brain had neuroprotection against focal cerebral ischemic injury. A total of 85 male Sprague–Dawley rats were randomly assigned to five groups (n = 17 in each). The 2 Gz, 4 Gz, 6 Gz and 8 Gz groups were subjected to 3 min exposures at +2 Gz, +4 Gz, +6 Gz and +8 Gz, respectively for consecutive three times in animal centrifuge, with a 30-min rest period between each centrifuge run. The control group had no exposure to +Gz acceleration. Twenty-four hours after the last pretreatment, 12 rats in each groups were subjected to focal cerebral ischemia for 120 min and the other five rats in each group were sacrificed to measure the expression of heat shock protein 70(HSP70) in hippocampus by Western blot analysis. The results indicated that the 6 Gz and 8 Gz groups showed smaller infarct volume and lower neurologic deficit scores than the control group. The expression of HSP70 was significantly increased in 6 Gz and 8 Gz groups than those in the control group. Therefore, preconditioning with +Gz acceleration produced delayed neuroprotection against focal cerebral ischemia and that the neuroprotection may be related to the induction of HSP70.