Maniero G D, Carey C
Department of EPO Biology, University of Colorado, Boulder 80309, USA.
J Comp Physiol B. 1997 May;167(4):256-63. doi: 10.1007/s003600050072.
The effect of exposure to low temperatures (5 degrees C) on lymphocyte proliferation, leukocyte populations, and serum complement levels was examined in the northern leopard frog, Rana pipiens. Proliferation of T lymphocytes in response to phytohemagglutinin stimulation was significantly decreased in frogs kept for 2, 3, and 5 months at 5 degrees C compared to that of animals kept at 22 degrees C. A significant increase in the average percentage of neutrophils and a decrease in the mean percentage of eosinophils was observed in the blood of frogs held for 5 months in the cold compared to animals held at 22 degrees C for the same length of time. Mean serum complement activity after 1 month at 5 degrees C was significantly reduced in comparison to animals held at 22 degrees C and was not detectable after 5 months in the cold. Recovery of complement levels at room temperature (22 degrees C) was also examined after cold exposure. Complement levels were significantly higher than controls (at 22 degrees C) in frogs returned to 22 degrees C for 7 and 14 days after 5 months in the cold. After frogs were held at 5 degrees C for 1 month, serum complement levels increased significantly within 2 days after returning to 22 degrees C and continued to rise 5 and 9 days after warming. Injections with Aeromonas hydrophila following a 5-week exposure to 5 degrees C failed to cause death or observable symptoms of disease in frogs that were returned to 22 degrees C.
研究了低温（5摄氏度）暴露对北美豹蛙（Rana pipiens）淋巴细胞增殖、白细胞群体和血清补体水平的影响。与饲养在22摄氏度的动物相比，在5摄氏度下饲养2、3和5个月的青蛙，其T淋巴细胞对植物血凝素刺激的增殖显著降低。与在22摄氏度下饲养相同时间的动物相比，在寒冷环境中饲养5个月的青蛙血液中嗜中性粒细胞的平均百分比显著增加，而嗜酸性粒细胞的平均百分比则下降。与饲养在22摄氏度的动物相比，在5摄氏度下饲养1个月后，平均血清补体活性显著降低，在寒冷环境中饲养5个月后则无法检测到。还研究了冷暴露后在室温（22摄氏度）下补体水平的恢复情况。在寒冷环境中饲养5个月后，回到22摄氏度7天和14天的青蛙，其补体水平显著高于对照组（22摄氏度）。青蛙在5摄氏度下饲养1个月后，回到22摄氏度后2天内血清补体水平显著升高，并在升温后5天和9天继续上升。在暴露于5摄氏度5周后注射嗜水气单胞菌，并未导致回到22摄氏度的青蛙死亡或出现明显的疾病症状。
