Objective: To explore the mechanism of native Tibetan fetuses adaptation to hypoxia

we tried to find the different expression genes about mitochondrial function in the native Tibetan placents. Methods: In this study

the placents of native Tibetan and the high-altitude Han （ha-Han） were collected. After the total RNA extraction

the finally synthesized cDNAs were hybridized to mitochondrial array to find the altered expression genes between them. Then

the cytochrome c oxidase 17 （Cox17）

dynactin 2 （DCTN2

also known as p50）

and vascular endothelial growth factor receptor （VEGFR

also known as KDR） were chosen from the altered expression genes to further verify the array results using the SYBR Green real-time PCR. Because the altered expression genes （such as Cybb and Cox17） in the array results related to the activities of COXI and COXIV

the placental mitochondria activities of COXI and COXIV were measured to find their changes in the hypoxia. Results: By a standard of ≥1.5 or ≤0.67

there were 24 different expressed genes between the native Tibetan and the ha-Han placents

including 3 up-regulated genes and 21 down-regulated genes. These genes were related to energy metabolism

signal transduction

cell proliferation

electron transport

cell adhesion

nucleotide-excision repair. The array results of Cox17

DCTN2 and KDR were further verified by the real-time RT-PCR. Through the mitochondria respiration measurements

the activity of COXI in the native Tibetan placents were higher than that of ha-Han

there was no difference in COXIV activity between them. Conclusion: The altered mitochondrial related genes in the native Tibetan placents may have a role in the high altitude adaptation for fetuses through changing the activity of mitochondrial COX.