K. Narayan et al., EFFECTS OF 5-FLUOROURACIL OR TOTAL-BODY IRRADIATION ON MURINE BONE-MARROW MICROVASCULATURE, Experimental hematology, 22(2), 1994, pp. 142-148
This study was designed to investigate the changes in the murine bone
marrow microvasculature following treatment with 5-fluorouracil (5-FU)
or total-body irradiation (TBI). Seventy 8- to 12-week-old C3H male m
ice received either 5-FU at a dose of 150 mg/kg intravenously (IV) or
TBI at a dose of 8 Gy in two fractions 4 hours apart. Femurs from the
treated mice were studied by vascular casting, using mercer, and by ro
utine histology at days 5, 21, and 90. On day 5, the sinusoids were ma
rkedly swollen, and many were fused with one another. This was accompa
nied by significant reduction in the bone marrow cellularity. The cent
ral sinus was grossly dilated in both TBI- and 5-FU-treated groups. Th
e pronounced sinusoidal dilatation on day 5 appears to be a mechanical
effect due to hematopoietic cell loss resulting in relative negative
pressure outside the sinusoids. On day 21, the sinusoidal swelling had
subsided, and the overall vascular volume appeared to be restored to
normal. However, there was a large variation in the shape and size of
the sinusoids, and those present were not uniformly distributed. This
may to be due to the result of mechanical pressure from the reconstitu
ted hematopoietic cells. Whether these changes in the shape and distri
bution of sinusoids have functional significance-for instance, release
of the hematopoietic cells into the circulation-remains to be establi
shed.