[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.
Department of Integrative Chinese & Western Medicine, Hebei Medical University, Shijiazhuang 050017, China. wxc2222@163.com
Xiang-Chun
XC
Wu
Xiang-Feng
XF
Wu
Zhen-Hua
ZH
Jia
Yi-Ling
YL
Wu
D000818:Animals; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D002534:Hypoxia, Brain / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
D004365:Drugs, Chinese Herbal; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D042461:Vascular Endothelial Growth Factor A; C513941:tongxinluo; C467480:vascular endothelial growth factor A, mouse