[Effects of Tongxinluo on repeated hypoxic tolerance in mice].

OBJECTIVE: To observe the effects of Tongxinluo (TXL) on repeated hypoxic tolerance in mice and explore the underlying mechanisms. METHODS: Mice were randomly divided into groups of repeated hypoxia (control) and TXL according to body weights. The mice in each group were exposed to acute repeated hypoxia for 0 run (H0), 1 run (H1), 3 runs (H3) and 5 runs (H5). The animal's tolerance time of each hypoxic exposure was recorded. Western blot was used to measure the protein levels of hypoxia inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in cortex tissue. RESULTS: The hypoxic tolerance time in control and TXL groups significantly increased run by run. Both HIF-1alpha and VEGF proteins in two groups increased gradually. Compared with control group, the tolerance time in H1 of TXL group [(18.0 +/- 2.4) minvs (15.6 +/- 2.0) min], H3 [(68.3 +/- 13.2) min vs (41.7 +/- 9.0) min) and H5 (85.9 +/- 7.0) min vs (51.4 +/- 14.4) min] increased (P < 0.05 or P < 0.01); the HIF-1alpha protein expression in H1 of TXL group (0.95 +/- 0.04 vs 0.79 +/- 0.02), H3 (1.01 +/- 0.03 vs 0.85 +/- 0.02), H5 (1.16 +/- 0.02 vs 0.92 +/- 0.03) increased (P < 0.05 or P < 0.01); the VEGF protein expression in H3 of TXL group (1.14 +/- 0.02 vs 0.89 +/- 0.03), H5 (1.34 +/- 0.05 vs 0.99 +/- 0.07) increased (P < 0.05 or P < 0.01). CONCLUSIONS: Under repeated hypoxia, an organism has a strong adaptive ability. The rises of HIF-1alpha and VEGF may be an adaptive mechanism. TXL can increase obviously the adaptive ability of mice to hypoxia.

[Remote postconditioning by brief renal ischemia and reperfusion reduces acute myocardial ischemia and reperfusion induced myocardial apoptosis in rabbits].

OBJECTIVES: To observe the effects of renal ischemic postconditioning (RI-Post) on myocardial apoptosis in rabbits with acute myocardial ischemia and reperfusion. METHODS: All rabbits were subjected to 60 minutes ischemia by left anterior descending coronary artery occlusion (LADO) and 6 hours reperfusion. The rabbits are randomly divided into 3 groups (n = 8 in each group): (1) Ischemia-reperfusion (IR): LADO and reperfusion without additional intervention; (2) RI-Post: after 60 minutes of LADO, the left renal artery was occluded for 30 seconds and reperfused for 30 seconds and repeated 3 times, then the coronary artery was reperfused for 6 hours; (3) Medication intervention (MI): 10 minutes before coronary reperfusion, rabbits were treated with PKC antagonist GF109203X (0.05 mg/kg, IV), followed by RI-Post treatment and 6 hours coronary reperfusion. Myocardial apoptosis was measured by TUNEL and the myocardial Bcl-2 and Bax protein expressions were assessed by immunohistochemistry. RESULTS: Compared with the IR group and the MI group, myocardial apoptosis was significantly reduced (P < 0.05) and the Bcl-2 protein expression increased (P < 0.01) while the Bax protein expression decreased (P < 0.05) in the RI-Post group. CONCLUSIONS: Remote renal postconditioning applied right before the onset of coronary artery reperfusion can reduce the myocardial apoptosis induced by myocardial ischemia and reperfusion and up-regulate Bcl-2 while down-regulate Bax expression possibly by activation of protein kinase C.