Repetitive progressive thermal preconditioning hinders thrombosis by reinforcing phosphatidylinositol 3-kinase/Akt-dependent heat-shock protein/endothelial nitric oxide synthase signaling

ObjectiveWe compared the effects of modified progressive thermal preconditioning (PTP) and whole-body thermal preconditioning (TP) on stress responses, oxidative stress biomarkers, and arterial thrombosis formation, and explored their possible actions through phosphatidylinositol 3-kinase (PI3K)/Akt-dependent heat-shock protein (Hsp)/endothelial nitric oxide synthase (eNOS) pathways.MethodsWe divided four groups of 249 male Wistar rats into nonimmersed controls, TP, and one (1-PTP) and three consecutive cycles (3-PTP) of PTP in a 42°C water bath. We evaluated the stress responses, including hemodynamics, total energy transfer, endoplasmic reticulum (ER) stress marker glucose-regulated protein (GRP78), and blood reactive oxygen species level during TP or PTP treatment. We compared 1-PTP, 3-PTP, or TP effects on oxidative stress, intercellular adhesion molecule 1 (ICAM-1), Hsp70, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) activity, and vascular phosphorylated Akt (p-Akt) and eNOS (p-eNOS) expressions in a model of topical ferric chloride (FeCl3)-induced carotid artery thrombosis.ResultsPTP significantly (P < .05) induced less hemodynamic fluctuations, total energy transfer, ER, and oxidative stress than TP did. After 24 or 72 hours of treatment, 1-PTP, 3-PTP, and TP significantly (P < .05) elevated carotid arterial Hsp70, p-Akt, and p-eNOS expression, significantly (P < .05) depressed FeCl3-enhanced vascular 2′,7′-dichlorodihydrofluorescein diacetate, chemokine (C-X3-C motif) ligand 1 (CX3CL1), 3-nitrotyrosine, 4-hydroxynonenal, and ICAM-1 stain, PAI-1, and t-PA activity, leukocyte infiltration and thrombus size, and significantly (P < .05) delayed thrombus formation compared with controls. 3-PTP and TP had a higher (P < .05) protection than 1-PTP. PI3K/Akt, Hsp70, or N(G)-nitro-l-arginine methyl ester hydrochloride (L-NAME) inhibitors significantly (P < .05) depressed 3-PTP and TP-induced vascular protection.ConclusionsRepetitive PTP is better than single PTP to hinder thrombosis formation via reinforcing PI3K/Akt-dependent Hsp70/eNOS signaling.

Clinical RelevanceThis study implicates that a modified progressive thermal preconditioning (PTP) evokes less endoplasmic reticulum and oxidative stress in blood vessels than whole-body thermal preconditioning (TP). TP and PTP confer vascular protection via phosphatidylinositol 3-kinase (PI3K)/Akt-dependent heat-shock protein (Hsp)/endothelial nitric oxide synthase (eNOS) signaling. However, the vascular protection of three consecutive cycles of PTP (3-PTP) treatment is similar to TP but is more efficient than one PTP (1-PTP) cycle to hinder oxidative stress-induced thrombosis. 3-PTP provides more vascular protection than 1-PTP by inhibiting oxidative stress, chemokine, and adhesion molecule production in blood vessels through the reinforcement of PI3K/Akt-dependent Hsp/eNOS signaling. This study demonstrates that repetitive PTP is a safe, effective, and available strategy to protect against oxidative stress-induced thrombosis by reinforcing PI3K/Akt-dependent Hsp70/e-NOS signaling. We suggest that these preclinical data are sufficient to conduct a small, phase I proof-of-concept study and we may validate the outcome variables, including plasma and urinary nitrite and nitrate, or evaluate other physiologic parameters before and after surgery. PTP may be used as prophylaxis against vascular disease.