Yanbian University

Florfenicol (FLO) is widely used to treat bacterial respiratory diseases and hoof rot in cattle at various physiological stages. However, residues of FLO that accumulate in cattle may have adverse effects on animal health. Although FLO has been reported to exhibit embryotoxic and cytotoxic properties, the mechanism underlying its effects on bovine granulosa cells (GCs) remains poorly understood. In this study, we treated GCs with FLO at concentrations of 0, 10, and 100 μg/mL for 48 h to evaluate the effects of FLO on cell viability, mitochondrial function, and steroid hormone synthesis. The results showed that FLO treatment was associated with increased apoptosis, reduced GC proliferation, and impaired mitochondrial function. In addition, FLO treatment was accompanied by decreased ATP levels and increased intracellular reactive oxygen species (ROS). Furthermore, FLO exposure was associated with changes in PROG and E2 production, decreased protein expression of StAR and CYP11A1, and reduced levels of adenylate cyclase (AC), cyclic adenosine monophosphate (cAMP), and protein kinase A (PKA). The antioxidant N-acetyl-L-cysteine (NAC) partially attenuated these changes. In conclusion, our findings suggest that FLO exposure is associated with GC dysfunction and impaired steroidogenesis. These effects may be related to oxidative stress, mitochondrial dysfunction, and alterations in the cAMP/PKA/StAR signaling pathway, although direct causal relationships remain to be further elucidated.

Simple and effective monitoring of intracellular reactive oxygen species (ROS) variations caused by external oxidative stresses is very important in the biomedical field. However, there are many challenges in monitoring the ROS variations. It should consider both the entire cell population and individual cell, and whether it has the ability to monitor dynamically for a long time. In addition, a very important consideration is the generation of additional ROS caused by the monitoring process. Around these perspectives, in this study, an alloy-type probe displaying both circular dichroism (CD) and Raman signals is precisely designed and prepared. When cells are subjected to oxidative stress, the silver-element helical stripes on the surface of the intracellular alloy-type probe are etched by the generated ROS, resulting in a simultaneous decrease in the CD and Raman signals from the probe. The variation of ROS in macroscopic cell populations and individual cell can be monitored by CD and Raman, respectively. It is noteworthy that the monitoring process based on the present probe completely avoids the generation of additional ROS, which may be caused by the excitation light. The strategy proposed in this research improves the methods for monitoring intracellular ROS variation and provides a guiding framework for the design of probe materials in the future.

Perfluorinated compounds (PFCs) are emerging pollutants with strong bioaccumulation and stability, and potential risks to human health. Biological samples are usually limited in volume and content trace levels of target analytes, thus requiring in-situ and minimally invasive detection techniques (such as solid-phase microextraction (SPME), microfluidic chip analysis, and in vivo sampling). However, conventional detection methods are difficult to achieve accurate qualitative and quantitative analysis of trace PFCs. In this study, a rapid, in-situ and green analytical method was developed by combining nanoconfined liquid phase nanoextraction (NLPNE) with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of 9 PFCs in cerebrospinal fluid. The interlaced carbon nanofibers (CNFs) form multi-dimensional network nanopores, which provide favorable structural basis for the construction of NLPNE systems. The carbon nanofibers/carbon fibers (CNFs/CFs) was used to confined methanol, which was packed into the needle tip to fabricate a portable needle-tip extraction device. The confined methanol enhanced the extraction efficiency of 9 PFCs. Key parameters affecting extraction performance were optimized (including confined fluid type and volume, extraction time, desorption solvent type and desorption time). Under optimal conditions, the method exhibited excellent linearity (r ≥ 0.9955) in the range of 0.1-500 μg L^-1, with method limits of detection (MDLs) and limits of quantification (MQLs) ranging from 0.15 to 7.5 μg L^-1 and 0.50 to 24.98 μg L^-1, respectively. The intra-day and inter-day relative standard deviations (RSDs) were ≤12.99%, and the recovery of PFCs in cerebrospinal fluid samples was 70.56%-119.12% with RSD ≤11.63%. Compared with traditional methods, this method has the advantages of short time, small organic solvent, and simple operation ability, providing a novel and reliable approach for the real-time rapid analysis of trace PFCs in small-volume complex biological samples.