Effects of acute cold exposure on the expression of AQP-1 and AQP-5 in rat lung tissues

Abstract

To study the effect of acute cold exposure on the expression of aquaporin-1 (AQP-1) and AQP-5 in lung tissues and the changes of ultrastructural pathological changes after cold exposure in rats. Twelve male Wistar rats were randomly divided into control group (23±2)℃ and cold (-25℃) exposure group, the exposure time was 2 h. Rectal temperatures of the rats were measured immediately after cold exposure. The ultrastructural pathological changes of pulmonary tissue were observed by transmission electronic microscope. The mRNA expression of AQP-1 and AQP-5 was measured by RT-PCR. The protein expression of AQP-1 and AQP-5 was measured by Western blot. The body core temperatures(28.07±4.15)℃ of the cold exposure group were decreased significantly compared with the control group(37.33±0.25)℃ (P<0.05). In acute cold exposure group, the main pathological changes of pulmonary ulstructure included pulmoary epithelial basement membrane thickening, and karyopyknosis of AT-I cells, and vacuolization on the cytoplasm of (AT-Ⅱ) cells. After acute cold exposure, the levels of both mRNA and potein expressions of AQP-5 were decreased significantly (P<0.05) compared with those in the control group. while AQP-1 expression level showed no statistical significance between control group and cold exposure group. There might be some cause and effect relationship between lung tissue damage by cold exposure and the levels of mRNA and potein expressions of AQP-5 decreased after acute cold exposure.