Protective effect of Acer palmatum Thunb. leaf extract on mice with steroid-induced ocular hypertension

Background Ocular hypertension is a major risk factor for glaucoma, which is characterized by the presence of ganglion cells, ganglion disease, and an irreversible reduction in the number of ganglion cells and axons. Although the anti-inflammatory and detoxifying effects of the maple tree ( Acer palmatum Thunb.) leave extract are well known, it is unclear whether the extract can protect the eyes from ocular hypertension. Objective This study was conducted to investigate whether the alcohol extract from A . palmatum Thunb. leaves (KIOM-2015E) had a protective effect on eyes in an animal model of steroid-induced ocular hypertension. We investigated whether KIOM-2015E had a therapeutic effect on ocular diseases induced by elevated intraocular pressure (IOP) by reducing IOP. Results Ocular hypertension was induced in 9-week-old female C57BL/6 mice weighing 23–27 g with 4 weeks of steroid injection. After 4 weeks, 1 or 2 mg/mL of KIOM-2015E was instilled in the mice three times a day for 5 weeks. IOP was measured weekly, and the eyes were lysed after drug administration to investigate the changes in the histological parameters and the levels of anti-apoptotic proteins. IOP was elevated, OPN1SW levels were decreased in the retinal tissue, and GFAP levels were increased in the mice with induced ocular hypertension. IOP was lowered in a concentration-dependent manner in the mice treated with KIOM-2015E. KIOM-2015E was confirmed to have an inhibitory effect on the histological changes on the retina, activity of glial and astrocytic cells, and cell death. Conclusions Treatment with KIOM-2015E improved steroid-induced ocular hypertension. KIOM-2015E prevented retinal degeneration caused by increased ocular pressure by regulating protein levels and histological parameter expression in retina.