MMP9 and hypertensive disorder: However, after NAC intervention, there was no effect on hypertension, but the plasma TNF-α concentration reached normal levels, increased LVFS% and restricted the left ventricular posterior wall hypertrophy, and inhibited the activation of matrix metalloproteinase 2 and matrix metalloproteinase 9, which reduces the collagen deposition in the left ventricle, suggesting that NAC can slow down the process of CR in hypertensive rats and effectively protect cardiac function [19].