Whole body hyperthermia accelerates atherogenesis in low-density lipoprotein receptor deficient mice

THERMAL PRECONDITIONING PROTECTS THE HUMAN INTERNAL MAMMARY ARTERY FROM HYPOXIA/RE-OXYGENATION-INDUCED DAMAGE

1. Preconditioning has been demonstrated to ameliorate ischaemia/reperfusion injury in several cells and tissues. Therefore, in the present study we investigated whether preconditioning of human bypass grafts, internal mammary artery (IMA) and saphenous vein (SV) induces heat shock protein (Hsp) expression and reduces apoptosis in response to subsequent hypoxia/re-oxygenation damage in both vessels. 2. Internal mammary artery and SV rings, obtained from 30 patients (median age 66.5 years) undergoing coronary artery bypass grafting, were either incubated for 30 min at 42 degrees C (preconditioned) or kept in a standard incubator at 37 degrees C (not preconditioned). Six hours later, graft segments were exposed to 90 min hypoxia followed by a 30 min re-oxygenation period. Western blot, real-time quantative polymerase chain reaction analysis and apoptosis detection by the Terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling method were performed. 3. Heat-preconditioned IMA showed significantly increased protein expression of Hsp72 after hypoxia/re-oxygenation treatment compared with controls (median 9.1 vs 5.0 microg/mg total protein; P = 0.048). Expression of Hsp73 was weak and Hsp60 was not detectable in the IMA. 4. In the SV, neither protein nor mRNA expression of Hsp were significantly different between preconditioned and not preconditioned veins. 5. There were significantly fewer apoptotic cells in the intima of the preconditioned compared with not preconditioned IMA (P = 0.041) after hypoxia/re-oxygenation injury, whereas in the SV apoptosis was not significantly prevented by preconditioning. 6. Mild heat preconditioning before hypoxia/re-oxygenation injury is a stimulus for Hsp72 protein expression and a reduction in apoptosis in the human IMA.

Effect of environmental hyperthermia on gastrin, somatostatin and motilin in rat ulcerated antral mucosa

AIM: To study the effect of environmental hyperthermia on gastrin, somatostatin and motilin in rat ulcerated antral mucosa.

METHODS: Forty-two Wistar rats were equally divided into six groups, according to the room temperature (high and normal) and the treatment (acetic acid, normal saline and no treatment). Levels of gastrin, somatostatin and motilin in rat ulcerated antral mucosa were measured with a radioimmunoassay method.

RESULTS: The average temperature and humidity were 32.5 °C and 66.7% for the high temperature group, and 21.1 °C and 49.3% for the normal temperature group, respectively. Gastric ulcer model was successfully induced in rat injected with 0.05 mL acetic acid into the antrum. In rats with gastric ulcers, the levels of gastrin and motilin increased, whereas the somatostatin level declined in antral mucosa, compared with those in rats treated with normal saline and the controls. However, the change extent in the levels of gastrin, motilin and somatostatin in antral mucosa was less in the high temperature group than in the normal temperature group.

CONCLUSION: The levels of gastrin, somatostatin and motilin in rat ulcerated antral mucosal tissue remain relatively stable in a high temperature environment, which may relate to the equilibration of the dynamic system.