HM-61, a Korean native plant extract, inhibits high glucose-induced ocular vessel alteration in zebrafish and prevents the development of diabetic ocular complications in diabetic db/db mouse

Diabetes alters the structure and function of most cell types in the eye. The injury of ocular cell and retinal vasodilation are the hallmark of diabetic ocular changes. HM-61 is an 80% ethanolic extract of Litsea japonica (Thunb.) Jussieu, Korean native medicinal plant, with beneficial effects on diabetes. In this study, we investigated the preventive effects of HM-61 on diabetic ocular complications in zebrafish and diabetic db/db mouse. Tg(flk-1:EGFP) zebrafish larvae which specifically express EGFP in all blood vessels were immersed in high glucose medium with or without HM-61 for 5 days post fertilization (dpf). HM-61 (100 and 250mg/kg body weight) was also treated once a day orally for 12 weeks in db/db mouse. In zebrafish model of diabetes, HM-61 effectively inhibited high glucose-induced ocular vasodilation (p<0.01 vs. control). In diabetic db/db mouse, the treatment of HM-61 prevented the breakage of retinal-blood barrier and the injury of retinal vascular cells. In addition, diabetes-induced microvascular and neuronal cell apoptosis was significantly reduced in HM-61-treated db/db mouse (p<0.01 vs. vehicle). Similarly, the administration of HM-61 also inhibited the development of diabetic cataract through the inhibition of sorbitol accumulation in lens fibers. These results indicate that HM-61 could provide a valuable therapeutic approach against diabetic ocular complications.

Acknowledgement: This research was supported by a grant [ K10040] from the Korea Institute of Oriental Medicine (KIOM).