Effects Of Exogenous Testosterone On Small Coronary Arteries In Castrated Cholesterol-Fed Rabbits

Objective: Study on the effect of intravenous testosterone on the small coronary arteries in castrated cholesterol-fed rabbits.Methods: 35 male New Zealand white rabbits were randomly allocated to 5 groups: control group A, castrated group B, intravenous testosterone small dosage(3mg/kg) and castrated group C, intravenous testosterone physiological dosage (6mg/kg) and castrated group D, intravenous testosterone large dosage (12mg/kg) and castrated group E. ALL were fed with high cholesterol diet. At the end of the 12th week, the serum levels of testosterone (TT), estrogen (E2), estrogen/ testosterone (E2/TT) were measured , and microcirculation of the living bulbar conjunctiva were observed ,and all rabbits were killed by air embolism . Hearts were removed and kept in 10% formal in for a week . The ventricles were obtained for determination of the degree of arteriolosclerosis by computer image analysis system. The incidences of atherogenesis and intimal thickening and the ratio of the intimal area to total area (intimal area plus intraluminal area) and intimal/midtimal were determinated.Results:1, TT, E2and E2 /TT were same before the rabbits were castrated(P>0. 05). TT decreased significantly after castration ( P<0.05 ) , intravenous testosterone small dosage(3mg/kg) and castrated group C have a low plasma levels of testosterone, intravenous testosterone physiological dosage(6mg/kg) and castrated group D have a physiological plasma levels of testosterone, intravenous testosterone large dosage (12mg/kg) and castrated group E have a high plasma levels of testosterone (P<0. 05 ) . TheE2 in group D have no significantly after castration and intravenous testosterone (P>0. 05). E2/TT increased significantly after castration and decreased significantly after intravenous testosterone (P<0. 05).But group C and group E had a higher rate ( P<0. 05 ) and group D were not changed (P>. 05).2, The obstruction in living bulbar conjunctiva were markedly more serious in group B, C, E than those in-group A and D (P<0. 01).3, The incidences of atherogenesis and intimal thickening and the ratio of the intimal area to total area (intimal area plus intraluminal area) and intimal/midtimal were markedly more serious in group B, C, E than those in group A and D (P<0. 05).Conclusion:Intravenous testosterone physiological dosage (6mg/kg) has beneficial effect on lipids vascular endothelium and can release the obstruction microcirculation in castrated rabbits and decreased the incidences of atherogenesis and intimal thickening and the ratio of the intimal area to total area (intimal area plus intraluminal area) and intimal/midtimal, which are beneficial to against coronary artherosclerosis.