Differential expression of serum proteins in rats subchronically exposed to arsenic identified by iTRAQ-based proteomic technology-14-3-3 ζ protein to serve as a potential biomarker.

Arsenic is a multi-system toxicant. However, the mechanism of arsenic toxicity is not fully clarified and few effective protein biomarkers could be used for arsenic poisoning. This study was to investigate the differentially expressed proteins in the serum of rats subchronically exposed to arsenic. Sixty male rats were randomly divided into four groups, and the dose of sodium arsenite in drinking water for each group was 0, 2, 10, and 50 mg L-1, respectively. The exposure lasted for 12 weeks. An Isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic approach was used to identify the differentially expressed proteins in serum between control and 50 mg L-1 groups. A total of 201 serum proteins were identified by iTRAQ, of which 12 were significantly changed by arsenic exposure with two up-regulated and ten down-regulated proteins. One down-regulated protein 14-3-3 ζ, an abundant protein expressed in the brain, was verified by ELISA using serum samples and by immunohistochemical, real time PCR, and western blot methods using brain tissues in four groups. Our work provided valuable insight into the serum protein changes in rats exposed to arsenic, and indicated that 14-3-3 ζ may serve as a useful biomarker for nervous damage caused by arsenic poisoning.

[Technical optimization for extracting hypotensive active peptides from Agrocybe aegerita].

OBJECTIVE: To optimize the techniques for extracting hypotensive active peptides from Agrocybe aegerita. METHODS: The effects of the liquid/solid ratio, extraction time and temperature, pH value of the initial liquid on the extraction percentage (EP) of the hypotensive active peptides were investigated, and inhibition percentage (IP) of the extracts on angiotensin I-converting enzyme was determined. RESULTS: Optimal extraction of the hypotensive active peptides from Agrocybe aegerita was achieved with the liquid/solid ratio of 40:1, extraction time of 3 h, extraction temperature at 30 degrees Celsius;, and pH=8 of the initial liquid. The EP of the hypotensive active peptides from Agrocybe aegerita could reach 87.7% with IP of the extracts on angiotensin I-converting enzyme of 54.0%. CONCLUSION: This method is simple and efficient for extracting hypotensive active peptides from Agrocybe aegerita.