Changes in the rat heart proteome induced by exercise training: Increased abundance of heat shock protein hsp20.

Chronic exercise training elicits adaptations in the heart that improve pump function and confer cardioprotection. To identify molecular mechanisms by which exercise training stimulates this favorable phenotype, a proteomic approach was employed to detect rat cardiac proteins that were differentially expressed or modified after exercise training. Exercise-trained rats underwent six weeks of progressive treadmill training five days/week, 0% grade, using an interval training protocol.

The mTOR/p70S6K signal transduction pathway plays a role in cardiac hypertrophy and influences expression of myosin heavy chain genes in vivo.

Objective: Rapamycin inhibits p70 S6 kinase (p70(S6K)) activity and hypertrophy of cultured neonatal rat cardiac myocytes. The purpose of the present study was to determine whether rapamycin inhibits left ventricular (LV) hypertrophy in intact rats and whether it alters cardiac gene expression.

Methods: 300 g rats were subjected to aortic constriction (AC) or sham-operation (SH) and studied 2 and 3 days after surgery.