Effects of Stress Response to Surgical Procedures upon Secretion of Salivary Immunoglobulin A in Mice

Secretory immunoglobulin A (sIgA) plays an important role in mucosal immunity, and salivary levels change in response to social, psychological and physical stress. However, little is understood about how surgical stress affects salivary sIgA. The results of the present study showed that mouse salivary IgA concentration was significantly elevated immediately after surgery and returned to pre-surgical levels after 24 h. Thus, the surgery did not suppress IgA secretion under our experimental conditions, suggesting that mucosal immunity was not perturbed. Since the role of α-adrenergic receptors involved in IgA secretion has remained unclear under surgical stress, we further examined the effects of either α1-adrenergic (prazosin) or α2-adrenergic antagonist (yohimbine) on the salivary sIgA. Yohimbine, but not prazosin, antagonized the surgically induced salivary IgA enhancement, indicating mediation by α2-receptor stimulation. The mRNA for IgA was not altered in the salivary gland after surgery, suggesting that surgical stress did not stimulate IgA synthesis in the salivary gland cells. In conclusion, it is suggested that the surgical stress does not perturb mucosal immunity in our experimental model, although a transient increase of concentration of salivary IgA was observed immediately after surgical insult.