Exercise Preconditioning Plays a Protective Role in Exhaustive Rats by Activating the PI3K-Akt Signaling Pathway

Figure 1

EP provides protective effects on myocardial structure of exhausted rats. Con: sedentary control group; EE: exhaustive exercise group; EP: exercise preconditioning group; EP + EE: exercise preconditioning + exhaustive exercise group; LY + EP + EE : LY294002 (PI3K inhibitor) + exercise preconditioning + exhaustive exercise group; LY: LY294002 group. (a) Light microscopy showed changes in myocardial microstructure among the six groups. Original magnification was ×400. Images showed disorganization and breakage of myocardial fiber, cardiomyocytes degeneration and necrosis, and interstitial substance with edema in the EE group. The LY + EP + EE group and the EP + EE group showed EE-like microstructure damages, but the EP + EE group was slighter. The EP group showed that myocardial fibers were organized, thickened, and slightly swollen. Con and LY groups showed normal myocardial microstructure. (b) Transmission electron microscopy showed changes in myocardial ultrastructure. Magnification was ×15 K; bar = 1.0 μm. Con and LY groups showed normal myocardial ultrastructure. The EP group showed that mitochondria were slightly swollen morphologically. The EE group myocardial fibers fractured, the mitochondria were swollen morphologically, the mitochondrial membrane structure partially disappeared, and the mitochondrial cristae fused and even disappeared. In the EP + EE group, myocardial fiber rupture was less, the mitochondria were swollen, and partial mitochondrial membrane and mitochondrial cristae become blurred. EE-like ultrastructural damages were observed in the LY + EP + EE group.

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