Submitted to: Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 4/17/1999
Publication Date: N/A
Technical Abstract: A study was conducted in rats to confirm part of the working hypothesis that physiologic amounts of dietary boron are important for synthesis and maintenance of connective tissue and prevention of inflammatory disease. Weanling Sprague-Dawley male rats (35 +/- 5 g) were fed a low boron basal diet (~0.1 mg B/kg) supplemented with boron (as orthoboric acid) at 0 (BB) ) or 2 (BS) mg/kg. On d 42, blood (for assessment of cytotoxic/suppressor lymphocyte [+CD8a/-CD4-labelled] [CD8a], natural killer [+NKR-P1A/- CD11b/c-labelled] [NK], and neutrophil [NEU] count) was drawn from the tail artery immediately prior to 0.15 mg injection of M. butyricum in the subplantar region of the right hindpaw of all rats. Progression of the AIA was monitored by repeated measurement (d 55 and 69) of CD8a, NK, and NEU cells and by measurement (d 47, 49, 52, 54, 60, 62, 66, 68) of metatarsal region thickness of the left hindpaw. On d 55, boron increased d ( P < 0.015) CD8a (BB, 1.35 +/- 0.47; BS, 2.02 +/- 0.45 x 10**6 cells/mL and increased (P < 0.01) NK (BB, 0.22 +/- 0.10; BS, 0.42 +/- 0.13 x 10**6 cells/mL blood) concentrations. On d 69, boron decreased (P < 0.03) NEU concentrations (BB, 2.06 +/- 1.13; BS, 0.89 +/- 0.20 x 106 cells/mL blood). Four of 8, but only 1 of 7, rats fed the BB and BS diets respectively exhibited severe joint swelling at any time post injections. Also, paw swelling decreased (P < 0.01) at a faster rate in rats fed boron. The findings indicate that physiologic amounts of boron modulate the response of key immune cells to antigens and help control the normal inflammatory process.