Different effects of strenuous eccentric exercise on the accumulation of neutrophils in muscle in women and men

Abstract

The purpose of this study was to evaluate the sex differences in delayed onset muscle soreness (DOMS), torque, and accumulation of technetium-99m (Tc-99m) neutrophils in eccentric-exercised muscle. A group of 10 female and 12 male subjects took part in this study. The subjects completed a pre-test using the descriptor differential scale (DDS) to describe DOMS, and tests of concentric and eccentric torque of the right quadriceps. A volume of 100 ml of blood was taken by venipuncture for neutrophil labelling in the early morning of the exercise day. The Tc-99m neutrophils were re-infused intravenously before the eccentric exercise. The exercise stimulus consisted of 300 eccentric repetitions of the right quadriceps muscles. Radionuclide images of both quadriceps muscles (lateral views) were taken at 2 and 4 h. The DDS, and concentric and eccentric torques of the quadriceps were subsequently evaluated at 0 h, 2, 4, 20 and 24 h post-exercise. The presence of Tc-99m neutrophils was greater in the exercised leg than the non-exercised leg at 2 and 4 h post-exercise (P </= 0.013) and greater in the exercised leg of the women compared to the men at 2 h (P = 0.03). The DOMS had increased post-exercise (P < 0.001) and torque had decreased post-exercise (P </= 0.002) but the patterns were different between the sexes. We concluded that the sex influences the presence of Tc-99m neutrophils in the exercised muscle following eccentric exercise. In addition, different patterns of DOMS and torque were observed between the sexes after eccentric exercise, and require further investigation.

Lengthening contraction-induced inflammation is linked to secondary damage but devoid of neutrophil invasion

“…Our first finding is that repression of EIMD-triggered inflammation leads to a decreased appearance of secondary muscle damage. A second major finding is that the neutrophilic phase of inflammation is abrogated in this model of muscle trauma, which is contrary to the general belief that sterile traumatic insult in skeletal muscle triggers an inflammatory process that first goes through a neutrophilic invasion (15,17,27,28,40,51,52). It has also been assumed that the presence of neutrophils in a damaged tissue was necessary to attract circulating macrophages and to modulate their activity (42).…”

“…In one study, muscle biopsies were obtained preand post-EIMD and leukocytes were classified as neutrophils by use of histological staining (15). In another study performed with human subjects, neutrophils were localized after lengthening contractions by use of radionuclide imaging, and a small but significant increase in neutrophil signal density was seen 2 and 4 h postexercise (27). However, this type of imaging does not clearly tell whether neutrophils are still in blood vessels, in the interstitial space, or invading muscle cells.…”

Ameliorative Effects of Caffeic Acid Phenethyl Ester on an Eccentric Exercise-Induced Skeletal Muscle Injury by Down-Regulating NF-kB Mediated Inflammation

“…Specifically neutrophils and macrophages are recruited to damaged tissue where inflammatory mediators are generated by these immune cells [14,15,16,37]. It is known that COX-2 plays a crucial role in damaging tissue induced by the acute eccentric exercise [23].…”

“…The eccentric exercise induces skeletal muscle damage by inducing neutrophil and macrophage infiltration [14,15] to the site of injury within several hours, and this may last for up to 24 or even 48 h after exercise [16]. After being recruited to skeletal muscles, neutrophils release reactive oxygen species (e.g.…”

17β-estradiol attenuates exercise-induced neutrophil infiltration in men

“…Although serum activity levels of the muscle protein creatine kinase (CK) are generally lower in women at rest (6), after exercise they can either remain lower (56,63) or increase to levels similar to those found in men (26,59). With responses that can be attenuated (62), equal (63), or greater (44) in women, a consistent sex difference in exercise-induced inflammation has also not been determined. Factors beyond the influence of E2 alone that are better controlled in animals, such as sex organ removal and high-dose hormone replacement, may explain why there is more consistency in murine research yet there continues to be inconsistencies in human research.…”