Abstract:

Objective To study the effects of broad-spectrum mechanosensitive ion channels inhibitor ruthenium red on the regulation of intraocular pressure. Design Experimental research. Participants Human primary trabecular meshwork (TM) cells and 10 C57BL/6J mice. Methods Human primary TM cells were isolated and characterized based on cell morphology and “biomarkers” expression. Mechanosensitive currents in TM cells were detected by patch-clamp recording. A broad-spectrum mechanosensitive ion channel inhibitor, ruthenium red (RR) was applied to inhibit mechanosensitive currents in TM cells. 10 C57BL/6J mice were randomly divided into 2 groups. Saline (control group, n=5) or RR (RR group, n=5) was injected into the anterior chambers of mice, respectively. Intraocular pressure (IOP) was measured daily and outflow facility was measured at 12 days after injection. Main Outcome Measures mechanosensitive currents (pA), IOP (mmHg) and aqueous humor outflow facility (μl/min/mmHg). Results Mechanosensitive currents of RR group （-67.6±30.2 pA） was significantly lower than the mechanosensitive currents before administration（-309.7±65.9 pA）（P=0.003）. At the 10th day after the injection, IOP was decreased in RR group （14.67±2.11 mmHg） compared to vehicle control (17.85±3.66 mmHg) (P=0.0604). At 12 days after the injection, outflow facility in RR group mice (0.01058 ± 0.00236 μl/min/mmHg) was decreased significantly compared to that in controls (0.00324 ± 0.001352 μl/min/mmHg) (P=0.0273). The pumping rate in RR group mice（0.37±0.15 μl/min）was higher than that in controls (0.28±0.05 μl/min) (P=0.6278）to maintain certain level of pressure (15 mmHg). Conclusion Mechanosensitive currents in human primary TM cells can be inhibited effectively by RR. Outflow facility can be significantly reduced by RR. Meanwhile, aqueous humor production rate can be regulated by RR, which result in a reduction of IOP in mice. These results provide a novel therapeutic approach to lower IOP in glaucoma.

Key words: intraocular pressure, mechanosensitive ion channels, ruthenium red, aqueous humor outflow, aqueous humor production