Effects of High- Versus Moderate-Intensity Training on Neuroplasticity and Functional Recovery After Focal Ischemia

This study was designed to compare the effects of high-intensity interval training (HIT) and moderate-intensity aerobic training (MOD) on functional recovery and cerebral plasticity during the first 2 weeks after cerebral ischemia.

Rats were randomized as follows: control (n=15), SHAM (n=9), middle cerebral artery occlusion (n=13), middle cerebral artery occlusion at day 1 (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 (S_LT) and the maximal speed (S_max). Functional tests were performed at D1, D7, and D14. Microglia form, cytokines, p75^NTR (pan-neurotrophin receptor p75), potassium-chloride cotransporter type 2, and sodium-potassium-chloride cotransporter type 1 expression were made at D15.

HIT was more effective to improve the endurance performance than MOD and induced a fast recovery of the impaired forelimb grip force. The ionized calcium binding adaptor molecule 1 (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 p75^NTR overexpression is observed on the ipsilesional side together with a restored sodium-potassium-chloride cotransporter type 1/potassium-chloride cotransporter type 2 ratio on the contralesional side.

Low-volume HIT based on lactate threshold seems to be more effective after cerebral ischemia than work-matched MOD to improve aerobic fitness and grip strength and might promote cerebral plasticity.