Abstract
Purpose :
To develop a mouse glaucoma model with intraocular pressure (IOP) elevation and trabecular meshwork (TM) structural changes which is suitable for investigating stem cell-based therapy for TM regeneration.
Methods :
Human TM cells were treated with endoplastic reticulum (ER) stress inducers tunicamycin, brefeldin A and thapsigargin. Apoptotic and necrotic cells were detected by flow cytometry and TUNEL staining. ER stress markers were detected by immunofluorescent staining and Western Blotting. Thapsigargin was selected for in vivo study and was injected intracamerally or subconjunctivally into 7-8-week old C57BL/6 mice. Intraocular pressure (IOP) was measured regularly up to 9 weeks. Corneal endothelium was detected by ConfoScan and endothelial cell number was counted using MetaMorph software. Outflow facility was detected on an ex vivo perfusion system. ER stress marker expression on the TM tissue was confirmed by immunofluorescent staining and qPCR.
Results :
Human TM cells were induced to go apoptosis and necrosis after treatment with the ER stress inducers. The treated cells expressed ER stress markers GRP78, pPERK as well as myocilin by staining and western blotting. Mouse IOP was elevated starting from day 7 after thapsigargin injection and lasting up to 9 weeks. The average IOP elevation was between 4 and 8 mmHg comparing to the controls. Corneal endothelial cell number was reduced in both intracameral and subconjunctival injections mice for 49 percent and 33 percent, respectively. Outflow facility was reduced in both groups. Expression of ER stress markers and percentage of apoptotic cells were increased in the TM cells with thapsigargin injection.
Conclusions :
Thapsigargin, a Ca2+ pump inhibitor, induces TM cell ER stress and apoptosis in vitro and in vivo. Both intracameral and subconjunctival injection causes IOP elevation and TM cell apoptosis. This mouse model is ideal for studying stem cell-based therapy for TM regeneration and preventing glaucomatous vision loss.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.