经典名方泽泻汤的HPLC指纹图谱及多指标含量测定研究

目的建立经典名方泽泻汤的HPLC指纹图谱,结合化学模式识别技术对其进行分析,并测定泽泻汤中3种成分23-乙酰泽泻醇B、23-乙酰泽泻醇C和白术内酯Ⅲ的含量,为泽泻汤质量控制提供科学依据。方法采用Waters WAT054275C18色谱柱(250 mm×4.6 mm,5μm),以乙腈-水为流动相进行梯度洗脱,建立15批泽泻汤的HPLC指纹图谱,并采用"中药色谱指纹图谱相似度评价系统"、SPSS22.0及SIMCA14.1软件对15批泽泻汤的HPLC指纹图谱进行相似度评价及聚类分析(CA)、偏最小二乘判别分析(PLS-DA)等化学模式识别。同时测定23-乙酰泽泻醇B、23-乙酰泽泻醇C和白术内酯Ⅲ的含量。结果建立了15批泽泻汤的HPLC指纹图谱,相似度均0.94,标定了18个共有峰,指认出3个色谱峰,分别为11号峰白术内酯Ⅲ、15号峰23-乙酰泽泻醇C、16号峰23-乙酰泽泻醇B,CA和PLS-DA将15批泽泻汤样品分为2类,同时15批泽泻汤中23-乙酰泽泻醇B、23-乙酰泽泻醇C和白术内酯Ⅲ的质量分数分别为0.321～0.569、0.075～0.139、0.106～0.142 mg/g。结论 HPLC指纹图谱结合多成分同时测定的方法,快速、简便、重复性好,为泽泻汤及其制剂的质量评价提供参考。     

Deficiency of anti-inflammatory cytokine IL-4 leads to neural hyperexcitability and aggravates cerebral ischemia–reperfusion injury

Systematic administration of anti-inflammatory cytokine interleukin 4 (IL-4) has been shown to improve recovery after cerebral ischemic stroke. However, whether IL-4 affects neuronal excitability and how IL-4 improves ischemic injury remain largely unknown. Here we report the neuroprotective role of endogenous IL-4 in focal cerebral ischemia–reperfusion (I/R) injury. In multi-electrode array (MEA) recordings, IL-4 reduces spontaneous firings and network activities of mouse primary cortical neurons. IL-4 mRNA and protein expressions are upregulated after I/R injury. Genetic deletion of Il-4 gene aggravates I/R injury in vivo and exacerbates oxygen-glucose deprivation (OGD) injury in cortical neurons. Conversely, supplemental IL-4 protects Il-4^−/− cortical neurons against OGD injury. Mechanistically, cortical pyramidal and stellate neurons common for ischemic penumbra after I/R injury exhibit intrinsic hyperexcitability and enhanced excitatory synaptic transmissions in Il-4^−/− mice. Furthermore, upregulation of Nav1.1 channel, and downregulations of KCa3.1 channel and α6 subunit of GABA_A receptors are detected in the cortical tissues and primary cortical neurons from Il-4^−/− mice. Taken together, our findings demonstrate that IL-4 deficiency results in neural hyperexcitability and aggravates I/R injury, thus activation of IL-4 signaling may protect the brain against the development of permanent damage and help recover from ischemic injury after stroke.     

Melatonin induces apoptosis of colorectal cancer cells through HDAC4 nuclear import mediated by CaMKII inactivation

Melatonin induces apoptosis in many different cancer cell lines, including colorectal cancer. However, the precise mechanisms involved remain largely unresolved. In this study, we provide evidence to reveal a new mechanism by which melatonin induces apoptosis of colorectal cancer LoVo cells. Melatonin at pharmacological concentrations significantly suppressed cell proliferation and induced apoptosis in a dose‐dependent manner. The observed apoptosis was accompanied by the melatonin‐induced dephosphorylation and nuclear import of histone deacetylase 4 (HDAC4). Pretreatment with a HDAC4‐specific siRNA effectively attenuated the melatonin‐induced apoptosis, indicating that nuclear localization of HDAC4 is required for melatonin‐induced apoptosis. Moreover, constitutively active Ca²⁺/calmodulin‐dependent protein kinase II alpha (CaMKIIα) abrogated the melatonin‐induced HDAC4 nuclear import and apoptosis of LoVo cells. Furthermore, melatonin decreased H3 acetylation on bcl‐2 promoter, leading to a reduction of bcl‐2 expression, whereas constitutively active CaMKIIα(T286D) or HDAC4‐specific siRNA abrogated the effect of melatonin. In conclusion, the present study provides evidence that melatonin‐induced apoptosis in colorectal cancer LoVo cells largely depends on the nuclear import of HDAC4 and subsequent H3 deacetylation via the inactivation of CaMKIIα.     

Necroptotic TNFα-Syndecan 4-TNFα Vicious Cycle as a Therapeutic Target for Preventing Temporomandibular Joint Osteoarthritis

Temporomandibular joint osteoarthritis (TMJOA) is a chronic degenerative disease for which the underlying mechanism still remains unclear. Compared with apoptosis and autophagy, necroptosis causes greater harm to tissue homeostasis by releasing damage-associated molecular patterns (DAMPs). However, the role of necroptosis and downstream key DAMPs in TMJOA is unknown. Here, rodent models of TMJOA were established by the unilateral anterior crossbite (UAC). Transmission electron microscopy (TEM) and immunohistochemistry of receptor interacting protein kinase 3 (RIPK3)/phosphorylation of mixed lineage kinase domain-like protein (pMLKL) were conducted to evaluate the occurrence of necroptosis in vivo. The therapeutic effects of blocking necroptosis were achieved by intra-articularly injecting RIPK3 or MLKL inhibitors and using RIPK3 or MLKL knockout mice. In vitro necroptosis of condylar chondrocyte was induced by combination of tumor necrosis factor alpha (TNFα), second mitochondria-derived activator of caspases (SMAC) mimetics and carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]- fluoromethylketone (z-VAD-fmk). The possible DAMPs released by necroptotic chondrocytes were screened by quantitative proteomics and blocked by specific antibody. Translucent cytosol, swollen organelles, and ruptured cell membranes, features of necroptosis, were frequently manifested in chondrocytes at the early stage of condylar cartilage degeneration in TMJOA, which was accompanied by upregulation of RIPK3/pMLKL. Inhibiting or knocking out RIPK3/MLKL significantly prevented cartilage degeneration. DAMPs released by necroptotic condylar chondrocytes, such as syndecan 4 (SDC4) and heat shock protein 90 (HSP90), were verified. Furthermore, blocking the function of SDC4 significantly attenuated the expression of TNFα in cartilage and synovium, and accordingly increased cartilage thickness and reduced synovial inflammation. Thus, the necroptotic vicious cycle of TNFα-SDC4-TNFα contributes to cartilage degeneration and synovitis, and can serve as a potential therapeutic target for treating TMJOA. © 2022 American Society for Bone and Mineral Research (ASBMR).     

Suppression of PRDX4 inhibits cell proliferation and invasion of ectopic endometrial stromal cells in endometriosis

Abstract

Oxidative stress (OS) has been proposed to play a role in the development of EMs. Peroxiredoxins are a family of antioxidant proteins that exhibit peroxidase activity in a thioredoxin-dependent manner, protecting cells against OS. The Western blotting results showed that the relative expression of PRDX4 was significantly increased in ectopic endometria compared with the normal endometria of EMs-free (p?<?.05). The H₂O₂ concentration was also significantly higher in the ectopic endometrium. PRDX4 siRNA was transfected into primary ectopic endometrial stromal cells (EESCs). The viability of the transfected EESCs was measured by CCK-8 assay, and the results showed significantly decreased cell viability. Furthermore, the apoptosis rate and ROS generation in flow cytometry assays were significantly increased after the knockdown of PRDX4 expression (p?<?.05). Scratch assays and transwell assays revealed that decreased expression of PRDX4 mediated by siRNA inhibited EESC migration and invasion. In conclusion, these findings indicate the potential role of PRDX4 in the development of EMs and PRDX4 as a possible therapeutic target for EMs treatment.     

An Environmental Scan of the National and Provincial Diagnostic Reference Levels in Canada for Common Adult Computed Tomography Scans

Several regulatory bodies have agreed that low-dose radiation used in medical imaging is a weak carcinogen that follows a linear, non-threshold model of cancer risk. While avoiding radiation is the best course of action to mitigate risk, computed tomography (CT) scans are often critical for diagnosis. In addition to the as low as reasonably achievable principle, a more concrete method of dose reduction for common CT imaging exams is the use of a diagnostic reference level (DRL). This paper examines Canada's national DRL values from the recent CT survey and compares it to published provincial DRLs as well as the DRLs in the United Kingdom and the United States of America for the 3 most common CT exams: head, chest, and abdomen/pelvis. Canada compares well on the international scale, but it should consider using more electronic dose monitoring solutions to create a culture of dose optimization.