PLG and brain ischemia: Cerebral ischemia in rats led to the upregulation of the BDNF precursor protein (proBDNF), mature BDNF (mBDNF), and their processing enzymes, such as furin and prohormone convertases, in the intracellular milieu, and matrix metalloproteinases (MMPs) or plasmin in the extracellular milieu [27,50].