Nj. Willmott et Aa. Hussain, NON-RETINAL ABNORMALITIES ASSOCIATED WITH PROGRESSIVE RETINAL ATROPHY(PRA) IN THE MINIATURE-POODLE, Experimental Eye Research, 63(5), 1996, pp. 527-533
Osmotic fragility was examined in red blood cells taken from miniature
poodles with progressive retinal atrophy (PRA). In this study, the me
dian osmotic fragility for erythrocytes (concentration of NaCl require
d for 50% haemolysis) was found to be significantly lower for clinical
ly affected, compared to unaffected animals. These differences were ma
intained regardless of changes in erythrocyte incubation pH (7.0, 7.5)
. There was no difference in the slope parameter of erythrocyte osmoti
c fragility profiles for both sets of animals, indicating a similar va
riability of erythrocyte age. In groups of animals maintained with the
same diet and fasted for 12 hr, and in groups of animals with no diet
ary constraints, total plasma cholesterol was significantly lower for
affected, compared to unaffected animals. Red blood cell indices were
also assessed; mean corpuscular volume (MCV), mean corpuscular haemogl
obin (MCH), red blood cell count (RBC) and blood haemoglobin concentra
tion (Hb) were normal, while erythrocyte packed cell volume (PCV) was
significantly reduced for affected, compared to unaffected. Data from
this study suggest that the abnormal erythrocyte osmotic fragility of
affected animals is unlikely to be a consequence of a higher erythrocy
te surface area/volume ratio, higher plasma cholesterol concentration,
or greater proportion of new to old erythrocytes, and that a general
membrane defect might be associated with prcd in the miniature poodle.
(C) 1996 Academic Press Limited