  Background and Purpose: This study was designed to compare the effects of
high-intensity interval training (HIT) and moderate-intensity continuous
training (MOD) on functional recovery and cerebral plasticity during the first
2 weeks following cerebral ischemia. Methods: Rats were randomized as follows:
Control (n=15), SHAM (n=9), MCAO (n=13), MCAO-D1 (n=7), MOD (n=13) and HIT
(n=13). Incremental tests were performed at day 1 (D1) and 14 (D14) to identify
the running speed associated with the lactate threshold (SLT) and the maximal
speed (Smax). Functional tests were performed at D1, D7 and D14. Microglia
form, cytokines, p75NTR, KCC2 and NKCC1 expression were made at D15.
Results-HIT was more effective to improve the endurance performance than MOD
and induced a fast recovery of the impaired forelimb grip force. The Iba-1
positive cells with amoeboid form and the pro- and anti-inflammatory cytokine
expression were lower in HIT group, mainly in the ipsilesional hemisphere. A
p75NTR overexpression is observed on the ipsilesional side together with a
restored NKCC1/KCC2 ratio on the contralesional side. Conclusions-Low-volume
HIT based on lactate threshold appears to be more effective after cerebral
ischemia than work-matched MOD to improve aerobic fitness, grip strength and
might promote cerebral plasticity.
