Mp. Reilly et al., RED-BLOOD-CELL MEMBRANE AND DENSITY CHANGES UNDER AMBIENT AND HYPOXICCONDITIONS IN TRANSGENIC MICE PRODUCING HUMAN SICKLE HEMOGLOBIN, Experimental hematology, 22(6), 1994, pp. 501-509
Red blood cells (RBC) from patients with sickle cell disease (SCD) are
characterized by membrane lesions caused by cell sickling and oxidati
ve damage due to denatured hemichromes. We have developed three lines
of transgenic human sickle hemoglobin (Hb S) mice, which produce 30, 5
0, and 80% human beta(sickel) globin (h beta(s)), by crossing transgen
ic progeny with nonthalassemic, heterozygous, or homozygous beta-thala
ssemic mice, respectively. Transgenic mice that produce Hb A, develope
d in a similar fashion, were used as controls. RBC from each transgeni
c line were examined for pathologic changes. RBC from 50 and 80% h bet
a(s) mice sickle upon deoxygenation in vitro while RBC from 30% h beta
(5) mice and all Hb A mice do not. Density gradients of RBC from each
Hb S line, including those from 30% h beta(s) that do not sickle, show
broad distributions with increased dense fractions, similar to those
of patients with SCD. RBC from Hb S lines exhibit elevated membrane-as
sociated denatured hemoglobin (MADH) levels (0.250 +/- 0.080%) when co
mpared to RBC from nontransgenic (0.073 +/- 0.021%) and transgenic Hb,
A (0.062 +/- 0.033%) mice. Elevated MADH levels in RBC from the 30% h
beta(s) line suggest that membrane changes occur even though these ce
lls do not sickle. These Hb S-dependent pathologic changes suggest tha
t transgenic Hb S lines may be useful for the study of not only RBC si
ckling in vivo but also membrane oxidative damage and other chronic ch
anges attributed to abnormal properties of both oxygenated and deoxyge
nated Hb S.