Testosterone enhances estradiol's cardioprotection in ovariectomized rats

Area of Science:

• Cardiovascular Science
• Endocrinology
• Cell Biology

Background:

• Postmenopausal cardiovascular disease (CVD) risk increases due to declining estrogen and androgen levels.
• Hormone replacement therapy is a potential strategy for mitigating CVD risk in postmenopausal women.

Purpose of the Study:

• To investigate the individual and combined effects of estradiol (E(2)) and testosterone replacement on cardiac protection in ovariectomized (Ovx) rats.
• To determine the role of the β(2)-adrenoceptor (β(2)-AR) in mediating these protective effects.

Main Methods:

• Ovariectomized rats were treated with E(2) alone, testosterone alone, or a combination of E(2) and testosterone.
• Cardiac function and myocyte damage were assessed after ischemia/reperfusion (I/R) injury.
• The involvement of β(2)-AR was evaluated using a selective antagonist (ICI 118,551) and by measuring β(2)-AR expression.

Main Results:

• Both E(2) and testosterone replacement, alone or in combination, reduced myocyte damage (LDH release, apoptosis) and improved cell morphology after I/R.
• Combination therapy demonstrated superior cardioprotective effects compared to individual hormone treatments.
• The protective effects were abolished by the β(2)-AR antagonist, indicating its crucial role.
• Combination therapy also increased β(2)-AR expression.

Conclusions:

• Testosterone enhances the cardioprotective effects of estradiol in ovariectomized rats.
• Combined E(2) and testosterone replacement offers significant cardioprotection, potentially mediated through the β(2)-AR pathway.
• This study suggests a potential therapeutic application for combined hormone therapy in preventing CVD in postmenopausal women.