Background: Strenuous exercise increases apoptosis of intestinal lymphocytes (IL). Bovine lactoferrin (bLf), a protein found in milk products, affects lymphocyte apoptosis and the expression of TH1 and TH2 cytokines.
Objective: The purpose was to determine whether bLf affects apoptosis and TH1 (tumor necrosis factor α) and TH2 (interleukin-10) cytokine expression in IL of mice given strenuous exercise.
Methods: Female C57BL/6 mice (n = 89), given three bouts of treadmill exercise, were killed either immediately, 24 h after the last bout, or before initiation of exercise; within exercise conditions, mice were fed control (0% bLf) or bLf-supplemented (2% bLf) diet for 12 d until sacrifice. IL were enumerated, and apoptosis and cytokine expression were determined by Western blot analysis; markers of stress (corticosterone and iso-prostanes) were measured in the plasma by radioimmunoassay and direct immunoassay.
Results: Exercise increased IL loss (P < 0.05) and the expression of caspase 3 (P < 0.001), heat shock protein 70 (P < 0.01), and interleukin-10 (P < 0.05) in mouse IL; bLf did not alter these responses. However, bLf reduced tumor necrosis factor α expression in mouse IL (P < 0.05), possibly through decreased nuclear factor κB expression (P < 0.05) in the supplemented group.
Conclusions: Dietary bLf does not affect IL apoptosis after exercise but may confer intestinal protection through changes in cytokine expression, independent of exercise.