[Mechanism of losartan suppressing vascular calcification in rat aortic artery]

Area of Science:

• Cardiovascular Research
• Pharmacology
• Biochemistry

Background:

• Vascular calcification is a significant risk factor for cardiovascular disease.
• The role of angiotensin II receptor 1 (AT1R) in vascular calcification requires further elucidation.

Purpose of the Study:

• To investigate the inhibitory effect of the AT1R blocker losartan on vascular calcification in a rat aortic artery model.
• To explore the underlying molecular mechanisms, including smooth muscle cell apoptosis and the expression of key regulatory proteins.

Main Methods:

• Vascular calcification was induced in Sprague-Dawley rats using warfarin and vitamin K1.
• Rats received subcutaneous injections of losartan (10 mg/kg).
• Morphological changes, calcium deposition, gene and protein expression (BMP2, RUNX2, AT1R), and smooth muscle cell apoptosis were assessed using HE staining, Alizarin red staining, RT-PCR, Western blotting, TUNEL assay, and fluorescent immunohistochemistry.

Main Results:

• Warfarin and vitamin K1 successfully induced aortic vascular calcification.
• Losartan treatment significantly downregulated the mRNA and protein expressions of bone morphogenetic protein 2 (BMP2) and Runt-related transcription factor 2 (RUNX2) compared to the model group.
• Losartan treatment also significantly decreased smooth muscle cell apoptosis and AT1R expression.

Conclusions:

• The AT1R blocker losartan demonstrates an inhibitory effect on vascular calcification in the rat aortic artery model.
• Losartan mitigates vascular calcification by inhibiting smooth muscle cell apoptosis and reducing AT1R expression.
• Downregulation of BMP2 and RUNX2 expressions is a key mechanism through which losartan exerts its protective effects in vascular calcification.