curzoniae. These data indicated HIF-1 in O. curzoniae was not sensitive to CoCl2 vs. in mice,
suggesting O. curzoniae has potential enduring to environment hypoxia. IGF-1 protein of the liver
in M.oeconomus was much increased vs. in O.curzoniae and mice by CoCl2 challenging. In
contrast, the liver IGFBP-1 protein in O.curzoniae was significantly increase and lasted for 6-12h
with injection of CoCl2, compared with M.oeconomus, suggesting hypoxia-increased IGFBP-1 in
O.curzoniae may be one of the mechanisms by which to restrict IGF-mediated inhibitory role in
growth and development through a limited availability of plasma IGF. O.curzoniae is a well-
acclimatized species at the Tibetan plateau, as we proposed before, and is good model for
studying hypoxia. * This work is supported by the grant from NSFC (Major Project No.
30393134 and Project No. 30070289; 30270232).
234.
THE PROLIFERATION AND DIFFERENTIATION OF PC12 UNDER HYPOXIA. Ting
Wang
1
, Lingling Zhu
2
, Zhicheng Xiao
1
, Ming Fan
2
. Department of Anatomy, Singapore General
Hospital, Singapore
1
, Department of Brain Protection and Plasticity, Institute of Basic Medical
Sciences, Beijing, China
2
.
Objective: to understand the effects of intermittent and continuous hypoxia on the
proliferation and differentiation of PC12, a cell line originating from rat pheochromocytoma.
Methods: The cells were exposed to 3%, 10% and 20% O2 in culture by 10 minutes every 24 h
for four days or continuous in these environments up to 24h. Results: the proliferation of PC12
with intermittent hypoxia have no significant difference. However, with continuous hypoxia, the
cell growth was suppressed under 10% O2, but promoted under 3% O2, compared with 20%.
PC12 cells differentiate and grow out neurites when exposure to nerve growth factor (NGF) at
50ng/ml for three to four hours. The intermittent hypoxia did not change the morphological
appearance of PC12 cells as determined by phase contrast microscopy. But after about four hours
exposure to continuous hypoxia, there are more cells grow out neurites with 3% O2 than that of
20% O2. What's more, parts of the cells grow out much more short projections than neuron cells,
which made them more like neuroglia cells. Conclusions: continuous hypoxia effects the
proliferation and differentiation of PC12. RT-PCR and Western will be used to evaluate the level
of hypoxic induced factor (HIF). The work was supported by key grant of Natural Sciences
Foundation of China (30393130).
235.
THE CHANGES OF PULMONARY ARTERIAL PRESSURE AND THE SERUM LEVELS OF
NITRIC OXIDE IN PLATEAU PIKA. Xiaoqin Wang
1
, Zangong Wang
1
, Qiuhong Chen
1
, Zigong
Wang
1
, Jialing Wen
1
, Akio Sakai
2
. High Alt. Med. Res. Inst. Qinghai, PRC
1
, Shinshu University,
Medical School, Matsumoto, Japan
2
.
To investigate the pulmonary circulation in plateau pika ( Ochotona curzoniae ) at high
altitude and the relationship between the degree of pulmonary arterial pressure (Ppa) and the
serum levels of nitric oxide (NO) and nitric oxide synthase ( eNOS ), 15 pikas were captured and
experimented at 3780 m, 14 Wistar rats were living at 2260 m and transported to 3780 m for one
month before experiment, and as a control animals. Animals were anesthetized, a polyvinyl
catheter filled with heparinised saline was introduced into the right jugular vein and then guided
into the main pulmonary artery as ascertained by pressure monitor. The results showed that a
higher Ppa in rats ( 26.6±1.2 mmHg ) than those of the pikas (11.9±0.6 mmHg ) (P <0.01 ).
Meanwhile, the serum NO (55.40±3.76_mol/L ) and eNOS(1.33±0.12u/ml ) were lower in rats
than those in the pikas (87.49±5.74_mol/L, and 1.99±0.13u/ml, respectively, P<0.01). Also, there
was a negative correlation between the serum levels of NO and the Ppa (r=-0.84, P <0.01). It was
concluded that a higher NO levels and a lower Ppa in pikas may be an adaptive mechanism to
high altitude.
