Effect of mild hypothermia on the expression of aquaporin family in cultured rat astrocytes under hypoxic condition.
Aquaporins (AQPs) are a family of water-selective transporting proteins with homology to the major intrinsic protein (MIP) of lens, that increase plasma membrane water permeability in secretory and absorptive cells. In this study, we investigated the effect of mild hypothermia on the expression of AQP4, AQP5 and AQP9 in rat astrocytes cultured under hypoxic conditions. At 37 degrees C, a marked decrease in the expression of AQP4, AQP5 and AQP9 mRNAs was observed. However, at 32 degrees C (mild hypothermia), the expression of AQP5 mRNA was restored to its basal level. Interestingly, under mild hypothermia AQP4 mRNA expression transiently decreased and then increased about two-fold; while AQP9 mRNA expression decreased the same as at 37 degrees C. The changes in the expression of AQP4 and AQP9 proteins were confirmed by Western blot analysis. The restoration of the AQP4 and AQP5 expression at 32 degrees C from the hypoxia-induced decrease at 37 degrees C may play an important role in the reduction of brain edema under hypothermic conditions.
Fujita
Yoshihito
Y
Department of Anesthesiology and Medical Crisis Management, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya 467-8901, Japan.
Yamamoto
Naoki
N
Sobue
Kazuya
K
Inagaki
Masaaki
M
Ito
Hiroaki
H
Arima
Hajime
H
Morishima
Tetsuro
T
Takeuchi
Akinori
A
Tsuda
Takako
T
Katsuya
Hirotada
H
Asai
Kiyofumi
K
D000818:Animals; D020346:Aquaporins / Q000096:biosynthesis*; D001253:Astrocytes / Q000502:physiology*; D015153:Blotting, Western; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D007036:Hypothermia, Induced; D000860:Hypoxia / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D020346:Aquaporins; D012333:RNA, Messenger