热应激时下丘脑视上核和室旁核Fos蛋白的表达

为了探讨不同温度下,大鼠的行为表现及大鼠下丘脑视上核和室旁核内神经元Fos蛋白的表达情况,本研究将成年SD大鼠置于不同温度(24℃、34℃、38.5℃、42℃),相对湿度为60%的实验仓内60min,观察大鼠的行为表现;同时应用免疫组化染色技术,观察大鼠下丘脑视上核和室旁核内Fos阳性神经元的形态、分布和数量的变化。行为学结果显示:24℃时,大鼠无异常表现,直肠温度为36℃左右;34℃仅引起大鼠直肠温度升高至38℃左右,动物行为无明显变化;38.5℃和42℃时,大鼠直肠温度升高至39℃以上,最初大鼠精神萎靡,活动减少,但随后转为兴奋状态,出现惊跳、逃窜行为。免疫组化染色结果显示:24℃时,下丘脑视上核、室旁核内Fos阳性细胞较少;34℃时,Fos阳性细胞的表达量增加;38.5℃时,Fos阳性细胞数达到峰值;42℃时又降低,并出现三种Fos阳性细胞:即胞核为Fos阳性、胞浆为Fos阳性以及胞浆、胞核均为Fos阳性。以上结果表明下丘脑视上核、室旁核内Fos蛋白的表达随温度的升高而发生明显的变化,提示这两个核团参与了热应激过程。

HEAT STRESS INDUCED CHANGES OF FOS PROTEIN EXPRESSION IN HYPOTHALAMIC SUPRAOPTIC NUCLEUS AND PARAVENTRICULAR NUCLEUS OF RAT

To investigate the expression of Fos protein in the hypothalamic supraoptic nucleus(SON) and paraventricular nucleus (PVN) of rats treated with various temperature, the adult rats were located within the experimental incubator, the temperature within the incubator was regulated to 24℃、34℃、38.5℃ or 42℃ and the relatively humidity was 60%, for 60 minutes,and observe the rats’performance in the present study. Immunohistochemical method was used to observe the changes of expression, shape and number of Fos-positive neurons in SON and PVN. The behaviors results showed that At 24℃, the rats’performance was normal and the rectal temperature was about 36℃;At 34℃,the rats’behavior had no changes, and the rectal temperature raised to 38℃; At 38.5℃ and 42℃, the rats depressed at first and then came into emotional state. The immunohistochemical staining result show that At 24℃, Fos-positive neurons were rare in the hypothalamic SON and PVN;Fos-positive neurons increased at 34℃;Fos-positive neurons peaked at 38.5℃;Fos-positive neurons decreased at 42℃. Three different types of Fos-positive cells were found at 42℃: Fos protein only expressed in the nucleus, Fos protein only expressed in the cytoplasms, Fos protein can be found both in the nucleus and the cytoplasms. The results suggest that expression of Fos protein in the hypothalamic SON and PVN changes markedly when ambient temperature rises, and these two nuclei participate in regulating heat stress.