Introduction: In male mice, exhaustive exercise increases susceptibility to respiratory infection following intranasal inoculation with herpes simplex virus-1 (HSV-1), whereas moderate exercise decreases the risk of infection. These responses have been linked with altered macrophage antiviral resistance, among other immune mechanisms. Female mice appear to be better protected from death than male mice following HSV-1 infection, although their response to exercise stress is similar. The possible immune mechanisms, however, have not been explored.
Purpose: This study was conducted to examine gender differences in macrophage antiviral resistance following repeated moderate and exhaustive treadmill exercise.
Methods: Male (M, N = 36) and female (F, N = 36) CD-1 mice were randomly assigned to moderate exercise (Mod), exhaustive exercise (Exh), or control (C) groups. Exercise was done daily for 3 d; moderate exercise consisted of treadmill running for 90 min, whereas exhaustive exercise consisted of running to volitional fatigue (~50 min).
Results: Females had greater macrophage antiviral resistance to HSV-1 than males in C and Mod (P < 0.05), but not Exh; Mod increased resistance, whereas Exh decreased resistance similarly in both genders (P < 0.001).
Conclusions: These data suggest that altered macrophage antiviral resistance to HSV-1 may contribute to gender differences in in vivo resistance to HSV-1 respiratory infection at rest, as well as following moderate and exhaustive exercise.
1Division of Applied Physiology, Arnold School of Public Health; and 2Department of Pathology and Microbiology, School of Medicine, University of South Carolina, Columbia, SC
Address for correspondence: J. Mark Davis, Department of Exercise Science, 1300 Wheat St., Columbia, SC 29208; E-mail: firstname.lastname@example.org.
Submitted for publication August 2005.
Accepted for publication November 2005.