Indomethacin does not influence natural cell-mediated cytotoxic response to endurance exercise

Natural cell-mediated cytotoxicity (NCMC) has been shown to be attenuated d uring recovery from high-intensity or prolonged exercise. Two theories have been proposed to explain the transient suppression of NCMC: prostaglandin- induced inhibition of natural killer (NK) cell activity or a numerical redi stribution of NK cells. This study was designed to examine the effects of o ral indomethacin (a prostaglandin inhibitor) on NCMC before and after 1 h o f high-intensity running (85% maximal oxygen uptake). A secondary purpose w as to compare whole blood and isolated peripheral blood mononuclear cell as say procedures for assessing NCMC. Ten male distance runners completed two trials that were preceded by either 48 h of indomethacin (Indo; 150 mg/day) or no treatment (control). NK (CD3(-)/CD16(+)/CD56(+)) cell concentrations were significantly elevated postexercise but were not affected by Indo. NC MC was significantly suppressed at 1.5 h of recovery relative to preexercis e only with the whole blood assay procedure. Indo was not found to influenc e NCMC, leukocyte, or lymphocyte subset concentrations. Mean cytotoxic resp onse was significantly greater with the whole blood method.