Gender differences in rat aortic smooth muscle cell matrix metalloproteinase-9

Area of Science:

• Cardiovascular Biology
• Vascular Cell Biology
• Atherosclerosis Research

Background:

• Abdominal aortic aneurysms (AAAs) disproportionately affect men, but the underlying reasons remain unclear.
• Matrix metalloproteinase-9 (MMP-9) is implicated in AAA development.
• This study investigated potential gender-based differences in MMP-9 production by rat aortic smooth muscle cells (RASMCs).

Purpose of the Study:

• To test the hypothesis that gender influences MMP-9 production in RASMCs.
• To explore the role of estradiol in modulating MMP-9 activity in male aortic tissue.

Main Methods:

• Quantitative real-time PCR was used to measure MMP-9 and TIMP-1 gene expression in male and female RASMCs stimulated with IL-1beta.
• Western blotting and gelatin zymography assessed MMP-9 protein levels and activity.
• The effect of 17-beta-estradiol on MMP-9 activity was evaluated in cultured male RASMCs and in aortic explants from male rats.

Main Results:

• MMP-9 gene expression, protein levels, and activity were significantly higher in male RASMCs compared to female RASMCs.
• Tissue inhibitor of metalloproteinase-1 (TIMP-1) expression was also elevated in male RASMCs.
• While estradiol did not affect MMP-9 activity in cultured male RASMCs, it significantly reduced MMP-9 activity in aortic explants from male rats.

Conclusions:

• Male RASMCs exhibit greater production of MMP-9 and TIMP-1 compared to female RASMCs.
• These gender-related differences in MMP-9 may contribute to the higher incidence of AAAs in men.
• Estradiol shows a potential inhibitory effect on MMP-9 activity in the aortic tissue of male rats.