Iron is sequestered as ferritin in macrophages in skeletal muscle of vitamin E-deficient rabbits.

Abstract

Weanling rabbits were fed a purified diet with or without vitamin E supplementation to evaluate the abnormal sequestration of iron in skeletal muscle associated with vitamin E deficiency. A severe myopathy developed in unsupplemented rabbits within 3 to 4 weeks. At this time, the concentration of soluble nonheme iron in biceps femoris muscles had increased from 2.1 +/- 0.4 microgram/g wet weight (mean +/- SD) for six control rabbits to 4.3 +/- 1.4 for 10 vitamin E-deficient rabbits, and total nonheme iron had increased from 5.0 +/- 1.2 to 8.4 +/- 3.3. Soleus muscles had even greater increases in total and soluble nonheme iron concentrations. Intramuscular injection of iron-dextran caused large increases in total and soluble nonheme iron in noninjected muscle of vitamin E-deficient rabbits, which further exaggerated the difference between the two groups. By radioimmunoassay using an antibody to rabbit liver ferritin, the concentration of ferritin in biceps femoris muscles increased from 0.47 +/- 0.18 microgram/g wet weight for seven control rabbits to 6.34 +/- 1.70 for 14 vitamin E-deficient rabbits. Uptake of intravenously injected transferrin-bound iron into muscle of vitamin E-deficient rabbits was not increased in a short term experiment (6 h), but radioiron did accumulate in muscle in a long term experiment (6 days). There was no trapping of heat-damaged erythrocytes, no phagocytosis of intravenously injected carbon particles, and no erythrophagocytosis in muscle. An immunohistological staining method designed to detect ferritin in tissue sections stained muscle from normal rabbits very scantily but intensely stained macrophages in the muscle of vitamin E-deficient rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)