Effect of spleen surgeries on Escherichia coli distribution on the mononuclear phagocytic system

To avoid asplenic state, many approaches preserving the spleen have been proposed in the literature: splenorraphy, partial splenectomy with or without preservation of hilar vessels and splenic tissue auto-implants. Subtotal splenectomy, preserving the upper spleen pole nourished only by splenogastric vessels is an alternative when the splenic pedicle must be ligated. The purpose of this study was to evaluate the influence of partial, subtotal and total splenectomies on the distribution of Escherichia coli in the mononuclear phagocytic system.

Thirty-two rats divided into four groups were studied: sham operation (total spleen preservation), partial splenectomy, subtotal splenectomy and total splenectomy. Five weeks after surgeries, an aliquot of E. coli marked with tecnetium-99m was injected intravenously. The animals were killed 20min later and the spleen, lungs and liver were removed in order to determine the distribution of labeled bacteria.

The amount of E. coli in the splenic tissue was greater in the intact spleen group than in the partial or subtotal splenectomy groups. Phagocytosis through the spleen did not differ between the partial and subtotal splenectomy groups. The amount of bacteria in the lungs was greater in the partial than in the subtotal splenectomy group. The distribution of labeled bacteria was greater in the liver of animals submitted to subtotal splenectomy than in the other groups.

The upper splenic pole, supplied only by splenogastric vessels, has the ability to remove live bacteria from the blood stream, showing that effective blood clearance occurs even without vascularization through the splenic pedicle. Thus, the distribution of E. coli through the mononuclear phagocytic system shows different behavior depending on the type of splenectomy to which the animals are submitted.