Traditional Chinese medicine may prevent vision loss in diabetes patients

The researchers showed that SDE, a traditional Chinese medicine, exhibited an anti-inflammatory and anti-oxidative ability in protecting retinal cells from high-glucose (HG) treatment.

In diabetic patients, diabetic retinopathy is a significant cause of vision loss. Hyperglycemia-induced oxidative stress and accumulation of inflammatory factors lead to blood-retinal barrier dysfunction and DR pathogenesis.

In recent years, human retinal epithelial cells (ARPE-19) have been widely used as in vitro models for DR research. The retinal pigment epithelium (RPE) is a single layer of epithelial cells between the vascular choroids and the neurosensory retina. The different functions of RPE ensure that the normal structure and function of the retina are maintained. RPE dysfunction is reported to be one of the early events that occur before vision loss in DR. Hyperglycemia-induced oxidative stress in RPE plays a critical role in diabetic retinopathy.

Scoparia dulcis L. extract has recently been recognized for its pharmacological effects, including anti-inflammatory, anti-hyperlipidemia, anti-diabetic, and anti-oxidative activities. Due to its low price and fewer side effects, it has been a hot topic in clinical applications and experimental studies for DR treatment. However, the protective effect of SDE in diabetic retinopathy has not been thoroughly studied.

In the study, Heng-Dao Lin, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan, and colleagues treated high glucose (50 mM) in human retinal epithelial cells with different SDE concentrations. They analyzed cell viability, apoptosis, and ROS production. Also, they analyzed the expression of Nrf2, Akt, HO-1, and catalase, which showed that SDE dose-dependently reduced ROS production and attenuated ARPE-19 cell apoptosis in a high-glucose environment.

"We demonstrated that SDE exhibited an anti-inflammatory and anti-oxidative ability in protecting retinal cells from high-glucose (HG) treatment.," the authors wrote. "Moreover, we also investigated the involvement of the Akt/Nrf2/HO-1 pathway in SDE-mediated protective effects."

The study showed that SDE protects ARPE-19 cells from apoptosis and senescence by inhibiting high glucose-induced inflammation and oxidative stress. Protective effects of SDE were revealed to be mediated by the activation of AKT and Nrf2, which increase the expression of downstream phase II enzymes or anti-oxidative enzymes.

"Thus, SDE should be considered as a nutritional supplement that could benefit patients with diabetes, especially in preventing visual loss in DR," the authors concluded.

Reference:

Lin, H., Lee, Y., Chiang, C., Lin, Y., Shih, C. Y., Tsai, R., Lin, P., Lin, S., Ho, T., & Huang, C. (2023). Protective effects of Scoparia dulcis L. extract on high glucose-induced injury in human retinal pigment epithelial cells. Frontiers in Nutrition, 10. https://doi.org/10.3389/fnut.2023.1085248