Furthermore, it was also found that MMP-3 is also expressed in the perivascular cells, basement membrane, and ventricular choroid plexus in the infarction area, which may be involved in the degradation of the vascular basement membrane after cerebral ischaemia, destroying the BBB, and leading to leakage of plasma protein into the brain parenchyma or to brain oedema. The gene discussed is MMP3; the disease is infarction.