Toll-like receptor signaling in small intestinal epithelium promotes B-cell recruitment and IgA production in lamina propria.
Secretory immunoglobulin A (s-IgA) plays an important role in both gut and systemic immunity. This study aimed to investigate the production of s-IgA resulting from a CO2 pneumoperitoneum compared with a laparotomy. Using enzyme-linked immunosorbent assays, s-IgA in stool, malondialdehyde (MDA), and Toll-like receptor 4 (TLR4) in the ileal tissue were evaluated as markers for gut and systemic immune responses in an animal model. The rats were randomly divided into (i) anesthesia-only as the control group; (ii) laparotomy-only as the open group; and (iii) CO2 pneumoperitoneum-only as the pneumoperitoneum group. To evaluate the gut immune system in a time-dependent manner, each group was further divided into short- and long-time subgroups. s-IgA levels did not increase in the open group but significantly increased in the pneumoperitoneum group compared with the control group (p < 0.05). In addition, s-IgA levels in the long-time subgroup significantly increased compared with the short-time subgroup of the pneumoperitoneum group (p < 0.05). TLR4 levels steeply and gradually increased in the open and pneumoperitoneum groups, respectively. MDA levels in the pneumoperitoneum group increased during the early phase and were significantly higher than those in the open group at 24 h (p < 0.05). This study demonstrated that s-IgA levels in stool increased in the pneumoperitoneum group compared with the open group, suggesting that CO2 pneumoperitoneum may cause transitory damage to the intestinal mucosa.