Fujita Yoshihito, Yamamoto Naoki, Sobue Kazuya, Inagaki Masaaki, Ito Hiroaki, Arima Hajime, Morishima Tetsuro, Takeuchi Akinori, Tsuda Takako, Katsuya Hirotada, Asai Kiyofumi
Department of Anesthesiology and Medical Crisis Management, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya 467-8901, Japan.
Neurosci Res. 2003 Dec;47(4):437-44. doi: 10.1016/j.neures.2003.08.006.
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.
水通道蛋白（AQPs）是一类与晶状体主要内在蛋白（MIP）具有同源性的水选择性转运蛋白，可增加分泌细胞和吸收细胞的质膜水通透性。在本研究中，我们调查了轻度低温对缺氧条件下培养的大鼠星形胶质细胞中AQP4、AQP5和AQP9表达的影响。在37℃时，观察到AQP4、AQP5和AQP9 mRNA的表达显著降低。然而，在32℃（轻度低温）时，AQP5 mRNA的表达恢复到基础水平。有趣的是，在轻度低温下，AQP4 mRNA表达短暂降低，然后增加约两倍；而AQP9 mRNA表达与37℃时一样降低。通过蛋白质印迹分析证实了AQP4和AQP9蛋白表达的变化。32℃时AQP4和AQP5表达从37℃时缺氧诱导的降低中恢复，这可能在低温条件下减轻脑水肿中起重要作用。
