ObjectiveTo explore the mechanisms through which Si Junzitang （SJZD） ameliorates Alzheimer's disease （AD） induced by scopolamine （SCOP） in mice and the PC12 cell model induced by H₂O₂ based on the Kelch-like ECH-associated protein 1 （Keap1）/nuclear factor erythroid 2-related factor 2 （Nrf2）/heme oxygenase-1 （HO-1） signaling pathway. MethodsIn the animal experiments， an AD model was established in mice by intraperitoneal injection of SCOP （3 mg·kg^-1）. Morris water maze and open field tests （OFT） were conducted to assess learning and memory abilities. Hematoxylin-eosin （HE） staining and Nissl staining were performed to observe pathological changes in neurons. Immunofluorescence was used to detect amyloid β-protein_1-42 （Aβ_1-42） expression， and immunohistochemistry was employed to detect phosphorylated （p）-Tau expression. Transmission electron microscopy （TEM） was employed to observe ultrastructural changes in hippocampal neurons and synapses. Biochemical methods were used to measure the levels of acetylcholine （ACh）， acetylcholinesterase （AChE）， superoxide dismutase （SOD）， malondialdehyde （MDA）， catalase （CAT）， and lactate dehydrogenase （LDH）. Real-time PCR and Western blot were employed to measure the mRNA and protein levels of molecules in the Keap1/Nrf2/HO-1 pathway in the hippocampus. In the cell experiments， a PC12 cell model of oxidative damage model was established with H₂O₂. Cell count kit-8 （CCK-8） assays and flow cytometry were adopted to measure cell viability and apoptosis rates， and Western blot was employed to quantify the expression levels of proteins in the Keap1/Nrf2/HO-1 pathway. ResultsThe animal experiments showed that compared with the model group， the SJZD and donepezil groups showed shortened escape latency （P<0.01）， increased time in the target quadrant and platform crossings， and increased movement distance and duration in the central area of the open field （P<0.05， P<0.01）. HE and Nissl staining showed more organized neurons and increased Nissl bodies in the drug intervention groups （P<0.05， P<0.01）， and the Aβ_1-42 and p-Tau expression levels were downregulated （P<0.05， P<0.01）. TEM revealed reduced ultrastructural damage in hippocampal neurons and synapses in the drug intervention groups. In addition， the drug intervention groups showed declined levels of MDA， LDH， and AChE （P<0.05， P<0.01）， elevated levels of SOD， CAT， and ACh （P<0.05， P<0.01）， reduced Keap1 expression and increased Nrf2， HO-1， and NQO1 expression in the hippocampus （P<0.05， P<0.01）. The cell experiments showed that compared with the model group， the SJZD-containing serum increased the cell viability （P<0.05， P<0.01）， and decreased total apoptosis rates （P<0.05， P<0.01）. The drug intervention groups showed upregulated protein levels of Nrf2 and HO-1 and downregulated protein level of Keap1 （P<0.05， P<0.01）. ConclusionSJZD demonstrates protective effects against SCOP-induced AD in mice and H₂O₂-induced damage in PC12 cells through antioxidant mechanisms mediated by the Keap1/Nrf2/HO-1 pathway.

This article discusses ethical issues related to corneal donation and transplantation, including the boundaries of living donor donation, the fairness of allocation, the limits of incentives and the risks of xenotransplantation. Based on ethical principles, a dialectical analysis is conducted in conjunction with laws, regulations and clinical practice. Living corneal donation should distinguish between therapeutic eye removal (acceptable) and corneal normal but retinal and optic nerve blindness donation (strictly limited); the current decentralized distribution system has regional unfairness and a unified national mechanism needs to be established; in the incentive policies, spiritual incentives should be advocated, economic incentives should adhere to the bottom line of no compensation but can be supplemented with humanitarian assistance, and rights incentives require national regulations; xenotransplantation faces animal ethics, religious taboos and public health risks, and a national regulatory framework for xenotransplantation needs to be established. On the basis of adhering to ethical principles, a special situation living donor review mechanism, a unified national distribution system, incentive policy implementation details and a national regulatory framework for xenotransplantation should be constructed to promote the sustainable development of corneal donation.

The incomplete degradation of tumour cells by macrophages (Mϕ) is a contributing factor to tumour progression and metastasis, and the degradation function of Mϕ is mediated through phagosomes and lysosomes. In our preliminary experiments, we found that overactivation of NADPH oxidase 2 (NOX2) reduced the ability of Mϕ to degrade engulfed tumour cells. Above this, we screened out liquiritin from Glycyrrhiza uralensis Fisch, which can significantly inhibit NOX2 activity and inhibit tumours, to elucidate that suppressing NOX2 can enhance the ability of Mϕ to degrade tumour cells. We found that the tumour environment could activate the NOX2 activity in Mϕ phagosomes, causing Mϕ to produce excessive reactive oxygen species (ROS), thus prohibiting the formation of phagolysosomes before degradation. Conversely, inhibiting NOX2 in Mϕ by liquiritin can reduce ROS and promote phagosome-lysosome fusion, therefore improving the enzymatic degradation of tumour cells after phagocytosis, and subsequently promote T cell activity by presenting antigens. We further confirmed that liquiritin down-regulated the expression of the NOX2 specific membrane component protein gp91 phox, blocking its binding to the NOX2 cytoplasmic component proteins p67 phox and p47 phox, thereby inhibiting the activity of NOX2. This study elucidates the specific mechanism by which Mϕ cannot degrade tumour cells after phagocytosis, and indicates that liquiritin can promote the ability of Mϕ to degrade tumour cells by suppressing NOX2.

The incomplete degradation of tumour cells by macrophages(Mφ)is a contributing factor to tumour progression and metastasis,and the degradation function of Mφ is mediated through phagosomes and lysosomes.In our preliminary experiments,we found that overactivation of NADPH oxidase 2(NOX2)reduced the ability of Mφ to degrade engulfed tumour cells.Above this,we screened out liquiritin from Glycyrrhiza uralensis Fisch,which can significantly inhibit NOX2 activity and inhibit tumours,to elucidate that suppressing NOX2 can enhance the ability of Mφ to degrade tumour cells.We found that the tumour environment could activate the NOX2 activity in Mφ phagosomes,causing Mφ to produce excessive reactive oxygen species(ROS),thus prohibiting the formation of phagolysosomes before degradation.Conversely,inhibiting NOX2 in Mφ by liquiritin can reduce ROS and promote phagosome-lysosome fusion,therefore improving the enzymatic degradation of tumour cells after phagocytosis,and subse-quently promote T cell activity by presenting antigens.We further confirmed that liquiritin down-regulated the expression of the NOX2 specific membrane component protein gp91 phox,blocking its binding to the NOX2 cytoplasmic component proteins p67 phox and p47 phox,thereby inhibiting the activity of NOX2.This study elucidates the specific mechanism by which Mφ cannot degrade tumour cells after phagocytosis,and indicates that liquiritin can promote the ability of Mφ to degrade tumour cells by suppressing NOX2.