Growth hormone increases BDNF and mTOR expression in specific brain regions after photothrombotic stroke in mice

Aims. We have shown that growth hormone (GH) treatment poststroke increases neuroplasticity in peri-infarct areas and the hippocampus, improving motor and cognitive outcomes. We aimed to explore the mechanisms of GH treatment by investigating how GH modulates pathways known to induce neuroplasticity, focusing on association between brain-derived neurotrophic factor (BDNF) and mammalian target of rapamycin (mTOR) in the peri-infarct area, hippocampus, and thalamus. Methods. Recombinant human growth hormone (r-hGH) or saline was delivered (0.25 μl/hr, 0.04 mg/day) to mice for 28 days, commencing 48 hours after photothrombotic stroke. Protein levels of pro-BDNF, total-mTOR, phosphorylated-mTOR, total-p70S6K, and phosporylated-p70S6K within the peri-infarct area, hippocampus, and thalamus were evaluated by western blotting at 30 days poststroke. Results. r-hGH treatment significantly increased pro-BDNF in peri-infarct area, hippocampus, and thalamus (p<0.01). r-hGH treatment significantly increased expression levels of total-mTOR in the peri-infarct area and thalamus (p<0.05). r-hGH treatment significantly increased expression of total-p70S6K in the hippocampus (p