Lonicerae japonicae flos ameliorates radiotherapy-induced mesenteric artery endothelial dysfunction through GTPCH1/BH4/eNOS pathway.

BACKGROUND: As a traditional Chinese medicine, Lonicerae japonicae flos (LJF) and its main component chlorogenic acid (CGA) have anti-oxidant, anti-bacterial and anti-tumor effects. However, there is no research on the potential of LJF for vascular protection in radiotherapy. PURPOSE: To elucidate the potential and possible mechanisms of the LJF extract and CGA in alleviating endothelial dysfunction caused by abdominal radiotherapy. METHODS: LJF was extracted with water and the CGA content was analyzed by HPLC. Male Sprague-Dawley rats received abdominal radiotherapy for 21 days. Seven days after irradiation, Laser Doppler and ex vivo vascular tension experiments were performed. Nitric oxide (NO), superoxide anion levels and tetrahydrobiopterin (BH4) content were detected. Western blot, flow cytometry and molecular docking were used. RESULTS: In the radiotherapy group, the mesenteric arterial blood perfusion, NO, and superoxide anion levels were significantly reduced; rats treated with the LJF extract or CGA showed a certain extent of recovery of these indicators. Vascular tension experiments showed that CGA and the LJF extract improved the vasodilation of mesenteric arteries. Cell experiments demonstrated that CGA increased the NO content and reduce superoxide anion production and cell apoptosis. The expression levels of GTPCH1/BH4/eNOS signaling pathway were significantly increased due to the use of the LJF extract or CGA in vivo and in vitro. CONCLUSIONS: Our study demonstrated for the first time that LJF and its main component, CGA could prevent abdominal radiotherapy-induced vascular endothelial dysfunction via GTPCH1/BH4/eNOS pathway. LJF could be a potential therapeutic herbal agent.

[Diurnal variations of grassland evapotranspiration over different periods in the Pailugou basin in the upper reach of the Heihe River, Northwest China.] / 黑河上游排露沟流域不同时期草地蒸散发的日变化.

Evapotranspiration (ET) is an important component of water cycle, but its measurement in high altitude mountainous region is quite difficult, resulting in the poor understanding of the temporal and spatial variations of actual ET in high altitude mountainous region. In this paper, a weighing lysimeter was used to measure the hourly ET in a grassland in the Pailugou basin in the upper reach of the Heihe River, Northwest China. Based on the measured data, diurnal variations of grassland ET over different periods were analyzed. Results indicated that snow and ice sublimation appeared during the freezing period, with a very different diurnal variation pattern compared with other three periods. During the period without sunshine, the amount of snow and ice sublimation was nearly constant. When the highest global radiation and lowest relative humidity appeared in the same period, the amount of snow and ice sublimation increased a little. The early growth period was a period when snow and ice started to melt, during which snowmelt evaporation and soil evaporation occurred at the same time. The growth period had the highest ET rate. Due to continuous rainfall events, maximum and minimum ET values appeared at the same hour. ET in the late growth period mainly came from soil evaporation, producing 3 peaks in diurnal variation, which was different from only one peak in both the early growth period and the growth period.