Plasma fibronectin levels after splenectomy and splenic autoimplantation in rats with and without dietary ascorbic acid supplementation

Abstract

The critical role of the spleen in protecting subjects from systemic bacterial infection is well known. Plasma fibronectin (PF), cold-insoluble globulin, and opsonic alpha2 surface binding glycoprotein, has regulatory influence on reticuloendothelial system clearance activity and it is important for maximal phagocytosis. Ascorbic acid (AA) also appears to play an important role in phagocytic cell function. The purposes of this study were to determine the effects of splenectomy and splenectomy with autoimplantation, with and without dietary AA supplementation, on PF levels. Six-week-old male Sprague-Dawley rats were divided into four experimental groups of 20 animals each: Nonoperated controls, sham-operated controls, totally splenectomized animals, and splenectomized animals with intraperitoneal autoimplantation. Each group was further randomly divided into two subgroups of 10 animals, those receiving dietary AA supplementation and those not receiving AA. PF levels were measured with a colorimetric assay immediately prior to and at 4 and 8 weeks after operation. Plasma AA determinations documented the effectiveness of dietary AA supplementation. PF levels in nonoperated and sham-operated controls increased significantly during the 8 weeks of experimentation. In contrast, PF levels decreased significantly following total splenectomy from 328 +/- 46 mcg/mL (mean +/- S.D.) to 285 +/- 46 at 4 weeks and rose to 303 +/- 77 at 8 weeks postoperatively in non-AA supplemented animals. Splenic autoimplantation eliminated this decrease in PF levels at 4 weeks. AA supplementation also protected against the decrease in PF levels in the splenectomized group. In the intragroup comparisons, AA supplementation did not produce a significant elevation of PF.(ABSTRACT TRUNCATED AT 250 WORDS)