The effect of percutaneous oestradiol on atheroma formation in ovariectomized cholesterol-fed rabbits.
OBJECTIVE
The aim of this study was to examine the effect of percutaneous oestradiol on the lipid profile and on atheroma formation using an animal model.


METHODS
The study was of 12 weeks duration. Fifty sexually mature female New Zealand White rabbits were divided into five groups of equal size. Two groups acted as controls and received normal rabbit chow. Rabbits in one of these groups were ovariectomized. The remaining three groups were ovariectomized but received 1% cholesterol enriched rabbit chow. One of these cholesterol-fed groups received 0.3 mg/kg percutaneous oestradiol daily whilst another received 0.1 mg/kg oral oestradiol daily. Measurements of concentrations of total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and triglycerides (TG) were made at the beginning and end of the study. Aortic atheroma formation was measured using computerized image analysis of uptake of Sudan III staining.


RESULTS
After 12 weeks there were significant increases in the mean concentrations of TC in the three cholesterol-fed groups compared with controls (P < 0.001). Changes in HDL-C and TG concentrations were less consistent. The mean area of aortic atheroma formation was significantly less in both the percutaneous oestradiol group (4.9%) and the oral oestradiol group (8.6%) compared with the non-oestrogen-treated cholesterol-fed group (19.5%) (P < 0.001, < 0.01 respectively).


CONCLUSIONS
These results suggest that percutaneous oestradiol has a direct protective effect on atheroma formation independent of serum concentrations of total cholesterol.
Haines
C J
CJ
Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong and The Prince of Wales Hospital, Shatin, New Territories. cjohnhaines@cuhk.edu.hk
James
A E
AE
Panesar
N S
NS
Ngai
T J
TJ
Sahota
D S
DS
Jones
R L
RL
Chang
A M
AM
D000284:Administration, Oral; D000818:Animals; D001161:Arteriosclerosis / Q000473:pathology / Q000517:prevention & control*; D002791:Cholesterol, Dietary / Q000008:administration & dosage; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000008:administration & dosage* / Q000097:blood; D005260:Female; D006937:Hypercholesterolemia / Q000473:pathology / Q000517:prevention & control*; D007279:Injections, Subcutaneous; D010052:Ovariectomy; D011817:Rabbits; D012016:Reference Values; D018709:Statistics, Nonparametric
D002791:Cholesterol, Dietary; D004958:Estradiol