Activation and apoptosis of murine peritoneal macrophages by acute cold stress

Effects of acute cold stress (5 degreesC for 24 h) on the functions of peri toneal macrophages and the mechanisms for controlling host homeostasis were investigated in mice. Phagocytic activity and expression of the cell surfa ce adhesion molecule CD11b/CD18 were markedly increased in peritoneal exuda te cells by acute cold stress. These alterations were attributable to an in creased number and phenotypical changes of adherent cells from acute cold-s tressed mice. On the other hand, a lipopolysaccharide-induced activity of s rc-family tyrosine kinase Fgr, an expression of interleukin-1 beta (IL-1 be ta) mRNA, and a bioactivity of IL-1 in the culture supernatants of adherent cells from acute cold-stressed mice were markedly lower than those from co ntrol mice. A time course study revealed that the number of adherent cells in peritoneal exudate cells was markedly increased in mice exposed to cold for 24 h but returned to normal numbers when mice were exposed to cold for 72 h, DNA fragmentation and Annexin-V+ cells were observed in peritoneal ex udate cells from acute-cold stressed mice. Thus, cold stress activated macr ophages but these macrophages were destined to be eliminated by apoptosis. (C) 2001 Academic Press.