Green tea extract enhances retinal ganglion cell survival and axonal regeneration in rats with optic nerve injury.

Current clinical treatments have not yet effectively cured progressive retinal ganglion cell (RGC) death and axonal degeneration after optic nerve (ON) injury. We previously demonstrated green tea extract (GTE) can reduce RGC death in rats after ischemic injury. Here, we aim to determine the prophylactic and therapeutic effects and mechanisms of GTE on RGC survival and axonal regeneration in rats with ON injury. GTE (275 or 550 mg/kg) was administered intragastrically for 7 d before or 14 d post-ON crush surgery in adult Fischer 344 rats. Rats with pre- or post-operative treatment of 275 mg/kg GTE showed significantly higher numbers of RGCs and regenerated axons post-ON injury with improved pupillary light reflex as compared to saline-treated rats. Akt and Erk p42/44 activation was higher in the retina of rats given 275 mg/kg GTE pre-surgery, whereas Stat3 activation was higher in those with 275 mg/kg GTE post-operation. Less activated microglia were observed in rats with pre-treatment of 275 or 550 mg/kg GTE. RNA sequencing analysis identified the downregulation of inflammation, apoptosis, and microglia activation genes in the retina of rats with pre- or post-treatment with 275 mg/kg GTE as compared to the saline-treated rats. In summary, this study revealed the prophylactic and therapeutic treatment effects of GTE on RGC survival and axonal regeneration in rats with ON injury, indicating a potential alternative treatment for traumatic optic neuropathy.

Varietal differences among the phenolic profiles and antioxidant properties of four cultivars of spine grape (Vitis davidii Foex) in Chongyi County (China).

Spine grape (Vitis davidii Foex) is an important wild plant species in South China. To provide sufficient experimental evidence for the strong antioxidant activity of spine grapes, four cultivars from Chongyi County, China, including three red varieties (Junzi #1, Junzi #2, and Liantang) and one white variety (Baiyu) were evaluated. The Junzi #1 had the highest phenolic content (total phenolic, flavonoids, flavanols, and anthocyanins) and the strongest antioxidant capacity (DPPH radical-scavenging capacity, cupric-reducing capacity and hydroxyl radical-scavenging activity) among the four varieties. HPLC analysis of spine grapes revealed that the (+)-catechin was the most abundant phenolics and the hydroxycinnamic acids were the major phenolic acids in the four varieties. Hierarchical cluster analysis showed that the Junzi #1 belongs to the group with high phenolic content and strong antioxidant power. The results suggest the Junzi #1 has the best health promoting properties, and the higher utilization value and potential for development.