39.
SCREENING AND IDENTIFICATION OF DIFFERENTIALLY EXPRESSED GENES FROM
HYPOBARIC HYPOXIC DELAYED PRECONDITIONING OF HIPPOCAMPUS IN MICE.
Youming Fan
1
, Yuqi Gao
1
, Jiang Huang
1
, Weigong Liao
1
, Mingchun Cai
1
. Department of
Pathophysiology and High Altitude Physiology, Third Military Medical University, Chong
1
.
Objective: To explore the differentially expressed genes wtih delayed preconditioning and in
normal mice hippocampus. Methods: Hypobaric hypoxic delayed preconditioning was produced
in a hypobaric chamber by maintaining 7000 m altitude for 2.5 h/d_3d. After 36h, total RNA was
isolated from hippocampus. cDNA was synthesized by SMART PCR. cDNA library of
differentially expressed genes from the hippocampus in hypobaric hypoxic preconditioning
(HHP) (forward) and control (backward) was constructed. 452 clones from forward and 74 clones
from backward were screened by reverse Northern hybridization. Results: The optical density
(OD) of 85 clones was increased by more than 2 times in the control than the preconditioning
group, while that of 217 clones was increased by that times in preconditioning than control, when
we used subtractive probes. With unsubtractive probes, OD of 44 clones was increased by above
2 times in the control than the preconditioning, while that of 135 clones was increased by that
times in the preconditioning group than the control. Some of these clones have been sequenced.
Analysis and comparison from the data of GenBank were performed. The similarity of all cDNA
was above 95% except one was 93%. All of these represented known genes. Mice cytochrome C
oxidase subunit 1, NADH dehydrogenase subunit 1 and 6, DELETED IN SPLIT-HAND/SPLIT-
FOOT 1 REGION(DSS1) and cDNA correspond to clone IMAGE: 5251089 of mice cDNA
library was increased in hippocampus of HHP mice and that cDNA corresponded to clone
IMAGE: 3593193, Mus musculus adult male olfactory brain cDNA and Mus musculus bladder
RCB-0544 MBT-2 cDNA were decreased. Conclusion: Genes have been differentially expressed
in hypobaric hypoxic delayed preconditioning hippocampus of mice. This may be one of the
important molecular mechanisms of delayed preconditioning. (By grant of NSFC 39730190 and
30393131).
40.
EFFECTS OF HYPOXIA ON EXPRESSION OF P450 MRNA IN CULTURED RAT
ASTROCYTES. Youming Fan
1
, Yuqi Gao
1
, Fuyu Liu
1
, Weigong Liao
1
. Department of
Pathophysiology and High Altitude Physiology, Third Military Medical University, Chong
1
.
Although it is well known that hypoxia induces cerebral blood vessels dilatation, the
mechanisms are still not well understood. Studies have shown that P450 2C11 in the astrocytes
catalyzes arachidonic acid (AA) into epoxyeicosatrienoic acids (EETs). EETs can cause
hyperpolarization of the cerebral arterial smooth muscle and induce vasodilation. As glutamate
levels rise up dramatically during hypoxia in vivo, this study investigated the effects of hypoxia
and glutamate on expression of P450 2C11 mRAN in cultured rat astrocytes. Cultured astrocytes
were randomly divided into 4 groups: glutamae group(G), hypoxic group(H), hypoxia +
glutamate group (H+G) and control (C). Cells of control group were exposed to nomorxic
condition, that of G and (H+G) were incubated with 100umol/L L-glutamate, then cells of H and
(H+G) were exposed to hypoxic condition (5%CO2, 95%N2) at 37. Each group had five
timepoints which included 0 h, 3 h, 6 h, 12 h, 24 h, respectively. Expression of P450 2C11
mRNA was detected with RT-PCR. The results showed that expression of P450 2C11 mRNA did
not change in H and C at all the above mentioned timepoints. While it was marked and
continuous increased from 6h to 24h in G and from 3 h to 24 h in G + H. P450 2C11 mRNA
expression was signifivcantly higher in G than both in H and C, and it was the highest of all
groups in G+H. Results suggested that glutamate and hypoxia + glutamate upregulate P450 2C11
expression. Hypoxia alone does not increase the expression of P450 2C11 mRNA but enhance the
upregulative effects of glutamate, which may be an important mechanism fo hypoxic cerebral
vascular dilation. (By grant of NSFC 39730190 and 30393131)
