OBJECTIVETo observe the effects of (-)doxazosin(DOX), (+)DOX and (+/-)DOX on serum lipid levels and the mortality rates of the rabbits fed by an atherogenic diet.

METHODSMale white New Zealand rabbits were fed by an atherogenic diet for 4 weeks. 8 rabbits whose serum TC <10 mmol/L were confirmed as normal diet group and were fed normally. 40 rabbits whose serum TC >10 mmol/L were randomly divided into 4 groups (n=10): atherogenic diet group, atherogenic diet with (-)DOX group, atherogenic diet with (+)DOX group and atherogenic diet with (+/-)DOX group, which were intraperitoneally injected with (-)DOX, (+)DOX and (+/-)DOX for 9 weeks respectively. Normal and atherogenic diet group were intraperitoneally injected with double distilled water. After 9 weeks administration of (+/-)doxazosin and its enantiomers, effects of the three agents on serum levels of total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) were observed.

RESULTSThe mortality rate of the rabbits fed by an atherogenic diet for 13 weeks was 40%, and it was much higher than that of the rabbits fed by a normal diet (10%). The mortality rates in the rabbits treated with (-)DOX and (+/-)DOX were lower than that in the rabbits fed by a normal diet (10%). Serum LDL-C level of the rabbits was increased markedly after 4 weeks of atherogenic diet, and it was further increased significantly (P < 0.05 and P < 0.01) during the continued 9 weeks of atherogenic diet. However, serum LDL-C levels were not further increased significantly (P > 0.05) during the continued 9 weeks of atherogenic diet in the rabbits treated with (-)DOX, (+)DOX and (+/-)DOX, respectively.

CONCLUSION(-)DOX and (+/-)DOX increase the survival rate and improve LDL-C disorder mildly in the rabbits fed by an atherogenic diet. The improvements in LDL-C induced by (-)DOX and (+/-)DOX, however, might not be the reason for exploration about the increased survival rate in the rabbits fed by an atherogenic diet.