Effects of atorvastatin on porcine aqueous humour outflow and trabecular meshwork cells

Primary open-angle glaucoma (POAG) with complex pathogenesis is one of the many major causes of blindness. It is widely accepted that the major cause of POAG is the dysregulation of the trabecular meshwork (TM), which regulates the resistance to aqueous humour outflow. Intraocular pressure is elevated with increasing outflow resistance in the conventional pathway, which consists of the TM and Schlemm's canal. The TM is a filter made up of extracellular matrix (e.g., collagens), most of which is organized into a network of beams covered by endothelial-like trabecular cells. Currently, lack of effective anti-glaucoma drugs acting on TM to normalize trabecular outflow represents a bottleneck for POAG therapy. Atorvastatin, a lipid-lowering drug, has been proven to be of benefit for POAG. The present study aimed to investigate the possible mechanisms of action of atorvastatin on the TM by using a porcine aqueous humour outflow model in vivo and TM cells in vitro. Perfusion of enucleated porcine eyes with atorvastatin (50-200 µM) for 2 h increased aqueous humour outflow (P<0.05, n=6), possibly via regulating the morphology of TM cells and the distribution of the cytoskeleton. Atorvastatin decreased adhesion molecules at the mRNA and protein level. No cytotoxicity of atorvastatin on TM cells was observed at concentrations of <100 µM. The atorvastatin-induced effects mentioned above were reversible after removal of the compound only if the atorvastatin concentration was <100 µM. The present study demonstrated that atorvastatin efficaciously elevated aqueous humour outflow, possibly due to affecting TM-cell morphology, cytoskeleton and cell junctions. Statins may be potential therapeutic agents for lowering intraocular pressure in POAG.