Effects of Strenuous Exercise and Moderate Exercise on Platelet Interaction with Nasopharyngeal Carcinoma Cell under Shear Flow in Men

Abstract

Nasopharyngeal carcinoma cell (NPC) is a common cancer in South China. Tumor cell-induced platelet aggregation (TCIPA) confers a number of advantages to the survival of the tumor cell and in its successful metastasis. Although shear–induced platelet activation is affected by acute exercise in an intensity-dependent manner, the effect of exercise on TCIPA remains to be determined. This study investigated how different intensities of exercise affect TCIPA in presence of various plasma proteins under shear flow by closely examining 18 sedentary healthy men who exercised strenuously (up to VO2max) and moderately (60%VO2max) on a bicycle ergometer. Before and immediately after exercise, TCIPA in the presence of albumin, fibrinogen, and fibronectin were measured by flow cytometer. The experimental results indicated the following: (1) following 5 dyne/cm2 of shear stress for 4 min, the mixtures of platelet and NPC in the presence of albumin, fibrinogen, and fibronectin were associated with higher percentages of TCIPA than those in the absence of plasma proteins; (2) fibrinogen-promoted TCIPA was increased by strenuous exercise and depressed by moderate exercise; and (3) there were no significant changes in albumin- and fibronectin- mediated TCPIA after this two exercise. We conclude that TCIPA induced by fibrinogen may be sensitized by strenuous exercise. In contrast, this cell-cell interaction can be suppressed by moderate exercise.