Effects of stress on mRNA transcripts of perforin and granzymes in splenic NK cells of mice

To explain the mechanism of decreasing the killing activities of NK cells by physical stress and psychological stress and to explore the difference between the two kinds of stress. The mice were received a consecutively physical stress or psychological stress respectively by using the communication box system. Then the levels of plasma corticosterone were determined by radioimmunoassay;A ~(51)Cr-release assay was used to measure the killing activities of NK cells;The number of splenic NK cells in mice was assessed by flow cytometry：And using RT-PCR analysis to detect the mRNA transcripts of perforin and granzymes A and B in murine splenocytes. After the physical stress or psychological stress, the levels of plasma corticosterone also increased and showed the highest level on 3th and 5th day respectively ,then went down gradually. Both physical stress and psychological stress decreased the number of splenic NK cells in mice, and inhibited their killing activities （P<0.05, P<0.01）. The two kinds of stress both reduced the mRNA transcripts of perforin. However physical stress decreased the mRNA transcripts of granzymes A ,but increased the mRNA transcripts of granzymes B. Psychological stress reduced the mRNA transcripts of granzymes B;It also decreased the mRNA transcripts of granzymes A,but the decreases were not significant. The physical stress and psychological stress can decrease the number of splenic NK ceils and inhibit their killing activities;But show different effecting on the mRNA transcript of perforin and granzymes A and B, that suggested there are different mechanism between physical stress and psychological stress in effecting on NK cells function.