MMP9 and diabetic retinopathy: It attenuates diabetic retinopathy by alleviating retinal inflammation through upregulation of SOCS3 expression, suppression of toll-like receptor 4 (TLR4) signaling, and reduction of MMP-9 production, and of inflammatory factors including TLR4/p38/NF-κB signaling pathways in BV2 cells [88].