Catalytical feature of optical nanoprobes of boron nitride quantum dots in the presence of Cu2+ for the determination of dopamine.

Monitoring the concentration of dopamine (DA) is vital for preventing and diagnosing DA related diseases. In contrast to the traditional sensing methods for DA, in which direct or indirect effects on the optical probes are often recorded, a novel sensing concept is disclosed based on as a result of the in situ formation of polydopamine (PDA) originating from the synergetic effect between boron nitride quantum dots (BNQDs) and Cu2+. In the co-presence of BNQDs and Cu2+, DA was catalytically oxidized to PDA, accompanied by an obvious color change from colorless to brown. In contrast to previous reports, in which BNQDs have been employed as an optical probe, herein, the BNQDs not only acted as the optical energy donor, but also as the catalysts for the formation of PDA. The quenching efficiency resulting from the inner filter effect and the electron transfer between the BNQDs and PDA was directly proportional to the concentration of DA, ranging linearly from 2 to 80 µM with a limit of detection of 0.49 µM. The present system exhibited an outstanding selectivity for DA among other interfering coexisting biomolecules. Furthermore, the practical application of the proposed platform was verified by assaying DA in human plasma samples, and satisfactory recoveries ranging from 101.24% to 111.98% were obtained. With the satisfactory reliability, repeatability and stability, the proposed simple sensor showed significant potential for use in DA detection in other biomedical applications.

Glutathione Regulated Inner Filter Effect of MnO2 Nanosheets on Boron Nitride Quantum Dots for Sensitive Assay.

Glutathione (GSH) can help the body maintain the function of the normal immune system and its level change is associated with a variety of diseases. To achieve the ultrasensitive assay of GSH, a "switch on" nanosensor is designed on the basis of GSH regulating the inner filter effect (IFE) of MnO2 nanosheets (MnO2 NS) on boron nitride quantum dots (BNQDs). Here, the fluorescence of BNQDs is quenched efficiently in the presence of redoxable MnO2 NS because of the superior light absorption capability; however, the introduction of GSH can trigger the decomposition of MnO2 to Mn2+ and weaken the IFE, causing the partial fluorescence recovery. The recovered fluorescence is dependent on the concentration of GSH. Under the optimal conditions, this sensing platform shows the response to GSH in the range of 0.5-250 µM with the detection limit of 160 nM. On the basis of the GSH activated reduction of MnO2 NS, the MnO2 NS/BNQDs nanoprobes exhibit good selectivity to GSH. The practical application of the proposed system is demonstrated by detecting the GSH in human plasma samples with satisfying results.

Increase of SOX9 promotes hepatic ischemia/reperfusion (IR) injury by activating TGF-ß1.

Ischemia/reperfusion (IR) injury causes damage in aerobically metabolizing organs or tissues, which is an essential injury mechanism in various clinical settings. SRY-related high mobility group-Box gene 9 (SOX9) is a transcription factor of the SRY family, modulating various cellular processes, including fibrosis formation and tumor growth. However, the effects of SOX9 on hepatic IR injury have not been explored. In the present study, a hepatic IR injury model was established, supported by a significant histological alteration with high Suzuki scores, and a remarkable up-regulation of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Importantly, we found that SOX9 was over-expressed in liver of mice after IR operation. Suppressing SOX9 markedly reduced inflammatory response, as evidenced by the reduced mRNA expressions of tumor necrosis factor α (TNF-α), interleukin (IL)-6 and IL-1ß and inactivation of inhibitor of κBα (IκBα)/nuclear factor (NF)-κB pathway. In addition, SOX9 suppression alleviated apoptosis in liver of mice after IR injury, as supported by the reduced number of terminal deoxyribonucleotidyl transferse (TdT)-mediated biotin-16-dUTP nick-end labelling (TUNEL)-staining cells and decreased expression of Caspase-3 in liver tissue sections. The role of SOX9 in accelerating hepatic IR injury was further confirmed in primary hepatocytes under hypoxiaand reoxygenation (HR) treatment by enhancing inflammatory response and apoptosis. Of note, we found that transforming growth factor (TGF)-ß1 was highly induced in liver of mice after IR injury. HR treatment also stimulated TGF-ß1 expressions in vitro. Significantly, SOX9 over-expression-induced inflammation and apoptosis were obviously reduced by pirfenidone (Pirf), TGF-ß1 inhibitor. In contrast, TGF-ß1 exposure to cells further enhanced inflammation and apoptosis in HR-operated cells either with SOX9 knockdown or over-expression. Therefore, we identified a novel SOX9-dependent pathway that contributed to hepatic IR injury through enhancing inflammation and apoptosis by activating TGF-ß1.

Development and validation of an UPLC-Q/TOF-MS assay for the quantitation of neopanaxadiol in beagle dog plasma: Application to a pharmacokinetic study.

Neopanaxadiol (NPD), the main panaxadiol constituent of Panax ginseng C. A. Meyer (Araliaceae), has been regarded as the active component for the treatment of Alzheimer's disease. However, few references are available about pharmacokinetic evaluation for NPD. Accordingly, a rapid and sensitive method for quantitative analysis of NPD in beagle dog plasma based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry was developed and validated. Analytes were extracted from plasma by liquid-liquid extraction and chromatographic separation was achieved on an Agilent Zorbax Stable Bond C18 column. Detection was performed in the positive ion mode using multiple reaction monitoring of the transitions both at m/z 461.4 → 425.4 for NPD and internal standard of panaxadiol. All validation parameters, such as lower limit of quantitation, linearity, specificity, precision, accuracy, extraction recovery, matrix effect and stability, were within acceptable ranges and the method was appropriate for multitude sample determination. After oral intake, NPD was slowly absorbed and eliminated from circulatory blood system and corresponding plasma exposure was low. Application of this quantitative method will yield the first pharmacokinetic profile after oral administration of NPD to beagle dog. The information obtained here will be useful to understand the pharmacological effects of NPD.

Up-regulation of miR-26a promotes neurite outgrowth and ameliorates apoptosis by inhibiting PTEN in bupivacaine injured mouse dorsal root ganglia.

Local anesthetic of bupivacaine may inhibit neurite outgrowth and induce apoptosis in mouse dorsal root ganglia (DRG) neurons. In this work, we intended to investigate the functional role of microRNA 26a (miR-26a) in regulating bupivacaine-induced nerve injury in DRG neurons. DRG neurons were extracted from C57BL/6 mice and cultured in vitro. Bupivacaine was applied in vitro and it induced apoptosis, inhibited neurite growth, and significantly down-regulated miR-26a gene in DRG neurons. MiR-26a mimic was then used to up-regulate miR-26a expression in DRG neurons. We found that miR-26a up-regulation promoted neurite outgrowth and reduced apoptosis in bupivacaine-injured DRG neurons. Luciferase assay and Western blot confirmed that Phosphatase and tensin homolog (PTEN) was down-stream target of miR-26a in DRG neurons. Ectopic PTEN up-regulation was then able to reverse the protective effect of miR-26a overexpression on bupivacaine-induced nerve injury in DRG neurons. Overall, this work demonstrated that miR-26a had a functional role in regulating bupivacaine-induced nerve injury in DRG neurons. Up-regulating miR-26a to suppress PTEN signaling pathway may be an effective method to protect local anesthetic-induced nerve injury in spinal cord.

Effects of PYRIN-containing Apaf1-like protein 1 on isoflurane-induced postoperative cognitive dysfunction in aged rats.

Postoperative cognitive dysfunction (POCD) is a prevalent neurocognitive disorder following surgery and anesthesia, particularly in elderly patients. Isoflurane is a widely used anesthetic agent, which is associated with the development of POCD; however, the precise mechanisms remain unclear. In the present study, aged rats were exposed to 2% isoflurane to establish a POCD model. The expression of PYRIN­containing Apaf1­like protein 1 (PYPAF1) was knocked down using a lentivirus containing specific short hairpin RNA. Subsequently, the spatial learning ability of rats was assessed using the Morris water maze. In addition, mRNA and protein expression levels were detected using reverse transcription­quantitative PCR and western blot analysis, respectively. Immunofluorescence double staining was also used to determine the expression of PYPAF1 and Iba­1 in the hippocampus. Neural apoptosis was observed using TUNEL­NeuN double staining. The results revealed that isoflurane exposure impaired the spatial learning ability of rats, while PYPAF1 knockdown alleviated cognitive impairment. In addition, isoflurane exposure induced activation of the PYPAF1 inflammasome, as evidenced by elevated expression of PYPAF1 and apoptosis­associated speck­like protein containing a caspase recruitment domain, while silencing of PYPAF1 partially reversed this effect. Furthermore, isoflurane exposure promoted the activation of microglia and caspase­1, and the secretion of interleukin (IL)­1ß and IL­18, all of which were alleviated following PYPAF1 silencing. Moreover, isoflurane exposure induced neuronal apoptosis, elevated the levels of Bax and cleaved caspase­3, and inhibited the expression of Bcl­2; all of these effects were partially abrogated following PYPAF1 silencing. In conclusion, the results of the present study indicated that PYPAF1 silencing partially abolished isoflurane­induced cognitive impairment, neuroinflammation and neuronal apoptosis. Therefore, PYPAF1 may be a potential therapeutic target for treatment of POCD.