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Ruiyi Ren, YI ZHOU, Thuy Duong Le, Enzhi Yang, Yiqin Du, Haiyan Gong; Morphologic Changes in Trabecular Meshwork Associated with Thapsigargin Induced Mouse Glaucoma Model. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3473.
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© ARVO (1962-2015); The Authors (2016-present)
Trabecular meshwork (TM) regeneration by cell-based therapy is a promising new approach for glaucoma treatment. An endoplasmic reticulum (ER) stressor, Thapsigargin (Thap), was previously reported to induce apoptosis and necrosis in cultured TM cells and elevation of intraocular pressure (IOP) in mouse eyes (Yang et al, ARVO 2016). This mouse glaucoma model can be used for further investigation of cell-based therapy for glaucoma. However, the effects of Thap treatment on TM morphology in this mouse model has not been investigated. This study aimed to investigate the morphologic changes in TM of Thap induced mouse glaucoma model.
C57BL/6 mice (7-8 weeks old) were injected with Thap (0.5µg/ml) intracamerally, subconjunctivally, or without any treatment as control (N=3 for each group). After measurements of IOP for 9 weeks, eyes were enucleated and fixed. Each eye was dissected to obtain anterior segment and then further dissected into eight wedges. Four wedges from each eye (one from each quadrant) were randomly selected to generate four radial and four frontal sections. All sections were then dehydrated, embedded, semi-thin (1µm) sectioned and imaged with light microscopy. One radial and one frontal sections from each eye were randomly selected and sectioned (80nm) for transmission electron microscopy (TEM). All sample processing and morphological analyses were performed in a masked fashion.
No significant difference in general morphology was found at light microscopic level between Thap injected groups and the control group. At TEM level, dilated rough ER, dissolution of internal structure of mitochondria, and necrosis-like disruption or rupture of cell and organelle membranes were observed in the inner wall of Schlemm's canal, juxtacanalicular tissue and the trabecular beams in both Thap injected groups, but not in control group. There seems no significant difference between two Thap treated groups with different injection methods.
Thap can induce cellular abnormalities including structural changes in ER, mitochondria, and cell membrane in all three types of cells in the TM. Intracameral and subconjunctival injections of Thap induce similar morphologic changes in the TM. Further study on Thap’s effects on TM matrix may elucidate the mechanisms by which Thap increases IOP.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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