Potential role of microRNA-503 in Icariin-mediated prevention of high glucose-induced endoplasmic reticulum stress.

BACKGROUND: Dysregulated microRNA (miRNA) is crucial in the progression of diabetic nephropathy (DN). AIM: To investigate the potential molecular mechanism of Icariin (ICA) in regulating endoplasmic reticulum (ER) stress-mediated apoptosis in high glucose (HG)-induced primary rat kidney cells (PRKs), with emphasis on the role of miR-503 and sirtuin 4 (SIRT4) in this process. METHODS: Single intraperitoneal injection of streptozotocin (65 mg/kg) in Sprague-Dawley rats induce DN in the in vivo hyperglycemic model. Glucose-treated PRKs were used as an in vitro HG model. An immunofluorescence assay identified isolated PRKs. Cell Counting Kit-8 and flow cytometry analyzed the effect of ICA treatment on cell viability and apoptosis, respectively. Real-time quantitative polymerase chain reaction and western blot analyzed the levels of ER stress-related proteins. Dual luciferase analysis of miR-503 binding to downstream SIRT4 was performed. RESULTS: ICA treatment alleviated the upregulated miR-503 expression in vivo (DN) and in vitro (HG). Mechanistically, ICA reduced HG-induced miR-503 overexpression, thereby counteracting its function in downregulating SIRT4 levels. ICA regulated the miR-503/SIRT4 axis and subsequent ER stress to alleviate HG-induced PRKs injury. CONCLUSION: ICA reduced HG-mediated inhibition of cell viability, promotion of apoptosis, and ER stress in PRKs. These effects involved regulation of the miR-503/SIRT4 axis. These findings indicate the potential of ICA to treat DN, and implicate miR-503 as a viable target for therapeutic interventions in DN.

Case report: Corticosteroids-induced acute diabetic peripheral neuropathy.

A 62-year-old man was diagnosed as IgA nephropathy. He had a pancreatic tumor operation 19 years ago and had a normal plasma glucose test every year. One month after the medication of prednisolone acetate was administered his fasting plasma glucose elevated to 7.1mmol/L while he manifested symptoms of thirst, frequent urination, and weight loss. Approximately 3 months after the steroids, he started complaining of numbness, weakness, and muscle cramp in his lower extremities, blood tests showed elevated plasma glucose and electromyography (EMG) revealed impairment of the peripheral nerves in the lower extremity, diabetic peripheral neuropathy was diagnosed. Mecobalamin and Acupuncture were employed and steroids were discontinued, 8 months later he recovered part of his strength and sensation. This case presents a specific adverse drug reaction of corticosteroids that causes diabetes mellitus and subsequently leads to peripheral neuropathy in an acute onset.

[Runoff Pollution Experiments of Paddy Fields Under Different Irrigation Patterns].

To study runoff and non-point source pollution of paddy fields and to provide a scientific basis for agricultural water management of paddy fields, paddy plots in the Jintan City and the Liyang City were chosen for experiments on non-point source pollution, and flood irrigation and intermittent irrigation patterns were adopted in this research. The surface water level and rainfall were observed during the growing season of paddies, and the runoff amount from paddy plots and loads of total nitrogen (TN) and total phosphorus (TP) were calculated by different methods. The results showed that only five rain events of totally 27 rainfalls and one artificially drainage formed non-point source pollution from flood irrigated paddy plot, which resulted in a TN export coefficient of 49.4 kg · hm⁻² and a TP export coefficient of 1.0 kg · hm⁻². No any runoff event occurred from the paddy plot with intermittent irrigation even in the case of maximum rainfall of 95.1 mm. Runoff from paddy fields was affected by water demands of paddies and irrigation or drainage management, which was directly correlated to surface water level, rainfall amount and the lowest ridge height of outlets. Compared with the flood irrigation, intermittent irrigation could significantly reduce non-point source pollution caused by rainfall or artificial drainage.

[Scenario analysis of integrated model of nutrients in the Miyun Reservoir and its watershed].

Supported by the integrated model of nutrients for the Miyun Reservoir in part I, effects of different control measures were studied on the water quality of the reservoir. Four scenarios were assumed and analyzed. Results of the base case scenario showed that TN concentration of the Miyun Reservoir had highly exceeded the environmental quality standard for surface water, and TP was relatively better. Furthermore, there were many regions that chlorophyll-a concentration exceeded 10 microg/L in the reservoir, and centralized in the reservoir area of Chaohe River. Scenario 1, 2 and 3 investigated effects of different pollution control measures on the water quality of the reservoir. Results showed that the control of nutrient input loads could improve the water quality greatly, especially control of TP loadings would limit algae growth effectively, and regions that chlorophyll-a concentration exceeded 10 microg/L even disappeared. The results indicated that some control measures, such as changing farming style, part treatment on stockbreeding pollution and reducing point source pollutant loadings were very effective and essential to decrease the eutrophic level of the reservoir.

[Integrated model of nutrients for the Miyun Reservoir and its watershed].

In recent years, the Miyun Reservoir faces severe problems of water quality and quantity due to continuous drought. In order to simulate and predict the eutrophic status of the Miyun Reservoir and its watershed, an integrated model was developed based on GIS and RS technology, which was composed of non-point source (NPS) simulation model, aquatic ecological-hydrodynamic model, and river water quality model. Ecological-hydrodynamic model was developed through coupling water quality analysis simulation program (WASP) with environmental fluid dynamics Code (EFDC). SWAT was selected as NPS simulation model, which could also perform water quality simulation in the river. Then the integrated model was calibrated using Markov Chain Monte Carlo method and verified using observed data. Results indicated that observed water quality data laid around the mode curves of simulation distribution, and which also dropped into the confidence interval on 80 percent credibility of water quality simulation distribution. In conclusion, the results show that the integrated model can meet the need of application.