Glycyrrhizin is a bioactive triterpenoid saponin extracted from a traditional Chinese medicinal herb, glycyrrhiza, and has been reported to protect the organs such as liver and heart from injuries. However, there is no report about the effects of glycyrrhizin on atrophic age‐related macular degeneration (AMD). This study investigated the effects of glycyrrhizin on retinal pigment epithelium (RPE) in vitro and retina of mice in vivo treated with sodium iodate (SI). Glycyrrhizin significantly inhibited SI‐induced reactive oxygen species (ROS), and decreased apoptosis of RPE in vitro. The underlying mechanisms included increased phosphorylation of Akt, and increased expression of nuclear factor erythroid 2‐related factor2 (Nrf‐2) and HO‐1, thereby protecting RPE from SI‐induced ROS and apoptosis. Furthermore, glycyrrhizin significantly decreased the apoptosis of retinal cells in vivo, resulting in the inhibition of thinning of retina, decreasing the number of drusen and improving the function of retina. These findings suggested that glycyrrhizin may be a potential candidate for the treatment of atrophic AMD in clinical practice.

Background: Age-related macular degeneration (AMD) is one of the major causes of blindness in the elderly over the age of 60. AMD is divided into dry AMD and wet AMD. Although there are certain treatment methods for wet age-related macular degeneration (AMD), there are no effective treatments for dry AMD yet, and finding new drugs or treatment methods for dry AMD has become a priority. For this purpose, this study explored Glabridin (Glab), an isoflavane found in the root extract of licorice, which has never been investigated in relation to eye diseases. Purpose: To investigate the effect of Glab on the sodium iodate (NaIO 3) induced retinal degeneration in vitro and in vivo. Methods: In vitro, cell viability and cytotoxicity were tested with methylthiazolyldiphenyltetrazolium bromide (MTT) assay among the groups of ARPE-19 cells. The cell apoptosis was tested with Hoechst 33342 staining and flow cytometry. The level of Reactive oxygen species (ROS) was measured to check the effect on oxidative stress. The protein expressions of phosphorylation of ERK1/2 and p38 were detected by Western blotting. In vivo, C57BL/6J mice were pretreated with Glab intraperitoneally for one week and continued for 4 weeks. NaIO 3 was given to mice through tail vein intravenous injection after 1 week of Glab administration. The retinas of mice were monitored by Optical coherence tomography (OCT) and electroretinography (ERG) at 1w, 2w, 3w, and 4w, respectively, followed by H&E staining. Results: In vitro, the Glab protected the retinal pigment epithelial (RPE) cells against oxidative stress and apoptosis by inhibiting phosphorylation of ERK1/2 and the p38 MAPK pathway. In vivo, Glab significantly prevented retinal damage by stopping the progression of retinal degeneration and reducing the formation of deposits on the RPE layer induced by NaIO 3. According to the findings of electroretinogram (ERG), Glab helped to maintain the normal function of the retina. Conclusion: Glabridin has a protective effect against retinal degeneration. It is suggested that Glab be further investigated for the treatment of retinal degeneration diseases.

Background: To investigate the safety and effectiveness of a modified transscleral suture through ex vivo tests.Methods: Ex vivo tests were performed in full-thickness porcine scleral pieces using modified knotless transscleral zigzag-shaped suture (Z-suture) fixation technology. The minimum traction force required to loosen or rupture the suture was assessed. The effects of different polypropylene sutures (10-0, 8-0), different suture spans (2.0, 3.0, 4.0 mm), different passes (3, 4, 5 passes), and scleral grooves were investigated. Results:The average minimum traction forces required to loosen 10-0 polypropylene sutured for 3.0 mm with a suture span of 3, 4, and 5 passes, were 0.18 (0.15-0.18), 0.22 (0.21-0.22), and 0.37 (0.37-0.37) N, respectively. The maximum traction force to prevent the suture from rupturing for the 10-0 polypropylene suture was 0.37-0.41 N in the sclera. The average of the minimum traction forces required to loosen the 8-0 polypropylene sutured with 5 passes and spanning 2.0, 3.0, and 4.0 mm were 0.37 (0.3 -0.39), 0.42 (0.42-0.45), and 0.50 (0.50-0.51) N, respectively, which were 14-28% higher than that of the 10-0 polypropylene suture under same conditions (all P values <0.01). In addition, there was no statistical difference (P=0.3258) for the 8-0 polypropylene suture used with a 3.0-mm suture span and 5 passes between conditions with or without scleral grooves. Conclusions:The minimum traction force required to loosen or rupture the suture in the sclera was associated with suture specification, suture span, and the number of passes, but was uncorrelated with double scleral grooves. The 8-0 polypropylene suture with double scleral grooves may be a more favorable choice for knotless transscleral fixation.