Lymphatic Vessels as an Entry Route of Enteric Bacterial Endotoxin into the Circulation -Experimental Study by Dog Intestinal Loop Method-

Mitsuru Kikuchi, Masatoshi Watanabe

The First Department of Surgery, School of Medicine, Iwate Medical University

The route of entry of endogenous endotoxin (Et) from the gut was studied experimentally. Endospecy, the most specific Et-assay and a New PCA for pretreatment were used for quantitative assessment of Et. Ileus models, consisting of an obstructed chamber 10 cm in length, were made in both the small and large bowel in dogs. Experiments were divided into three groups: (A) controls without an obstructed chamber (n=5); (B) 7 dogs with two chambers in the large bowel; (C) 17 dogs with chambers in both the jejunum and the ileum. To collect blood and lymph in series, catheters were inserted into the peripheral vein, portal vein and regional lymph vessels of the obstructed bowels. Each chamber was maintained at an intraluminal pressure of 40 mmHg. Only in group C, Et of Escherichia coli (EC) or Salmonella abortus equi (SA) was perfused in the chambers. In the controls, there was no significant difference in the plasma Et levels between the peripheral (13.3 pg/ml) and portal (13.6 pg/ml) veins 120 min after the operation and the lymphatic Et of the large bowel presented a sustained low level. In group B, the levels of lymphatic Et in the large bowel after obstruction (274.3 pg/ml) was significantly higher than that of group A (35.7 pg/ml), although the plasma Et levels of the peripheral and portal veins showed no change. In group C, the lymphatic Et levels in the jejunum and the ileum were 155.3 pg/ml and 96.7 pg/ml respectively after EC perfusion, significantly higher than each value (35.8 and 31.1 pg/ml) before perfusion. This tendency was also seen in the case of SA perfusion. Et concentration in the ileal lymph was lower than that in the jujunal lymph. It is worth noticing that the peripheral and portal Et did not change in either group B or C. It is concluded that the lymphatic vessels are the pathway of endogenous Et which is absorbed from the mucosa of the bowel. If colon bacteria reflux in the small bowel, there is a possibility that Et is also absorbed through the lymphatic system.

Reprint requests
Mitsuru Kikuchi The First Department of Surgery, School of Medicine, Iwate Medical University
19-1 Uchimaru, Morioka, 020 JAPAN

Accepted
September 9, 1992

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