中強度運動負荷中の唾液中分泌型免疫グロブリンAの変化 <原著論文>

唾液中分泌型免疫グロブリンA(secretory immunoglobulin A : SIgA)は上気道局所免疫機能の指標の1つとして知られている.SIgAは運動後に変動することが報告されているが,運動中の経時的変化については不明である.そこで,本研究は健常者を対象とし,中強度で60分間の自転車運動を行い,運動中および運動後の唾液分泌量,唾液中SIgA濃度,唾液中SIgA分泌量の経時的変化を検討した.その結果,運動開始15分後以降で唾液分泌量と唾液中SIgA分泌量は運動開始前と比較して有意に低下し,運動終了後15分で運動開始前のレベルに回復した.一方,唾液中SIgA濃度は運動中及び運動後に有意な変化を認めなかった.中強度運動中の唾液中SIgA分泌量の低下は,唾液中SIgA濃度ではなく,唾液分泌量の低下に起因することが明らかとなった.

Salivary secretory immunoglobulin A (SIgA) is well known as a marker reflecting immune function in the upper respiratory tract. Several reports demonstrated that salivary SIgA levels varied after exercise. However, serial changes in salivary SIgA levels during moderate exercise were still unknown. We measured salivary secretion rate, salivary SIgA concentration and secretion rate during and after moderate cycling exercise in healthy subjects. Salivary secretion rate and SIgA secretion rate were significantly decreased throughout exercise and returned the baseline levels at 15 min after exercise. On the other hand, no significant change in SIgA concentration was observed during and after exercise. These results suggest that the decrease in salivary secretion rate, but not salivary SIgA concentration, leads to decrease in salivary SIgA secretion rate during moderate exercise.