[Effects of acute cold exposure on pulmonary proinflammatory cytokine of rat]

To study the effects of acute cold exposure on the inflammation and pathologic injuries in pulmonary of rats, and explore the mechanism induced by cold stress.

Forty male Wistar rats were randomly divided into five groups(n = 8): control group (23 ± 2) °C 2.5 h, -25°C 0.5 h group, -25°C 1 h group, -25°C 2 h group and -25°C 2.5 h group. Rats were exposed to cold at -25°C and no wind by keeping them in a low temperature chamber except control group. Rectal temperatures of the rats were measured before and after cold exposure. The morphological changes of pulmonary were observed by the optics microscope. The levels of tumer necrosis factor-α(TNF- α), interleukin-6 (IL-6) and interleukin-β (IL-1β) in lung tissue homogenate were measured by ELISA.

Compared to the control group, body core temperatures of the -25°C 1 h group, -25°C2 h group and -25°C 2.5 h group were decreased significantly, and the D-values of rectal temperature were increased before and after cold exposure (P < 0.05). The infiltration of inflammatory cells and alveolar edema fluid appeared in the lung tissue of the -25°C 2.5 h group. The concentrations of tumor necrosis factor-α (TNF α), interleukin-6 (IL-6) and inter- leukin-1β (IL-1β) in lung tissue homogenate were increased significantly in -25°C l h group, -25°C 2 h group and -25C° 2.5 h group (P < 0. 05).

The infiltration of inflammatory cells and the increase in proinflammatory cytokine from pulmonary may lead to the lung tissue injury after acute cold exposure.