Retinal degenerative diseases are a group of blinding ocular disorders characterized by progressive and irreversible loss of retinal neural cells. They mainly include age-related macular degeneration and retinitis pigmentosa. At present, there are no curative clinical therapies capable of reversing the disease course. Patients have poor long-term visual prognosis, imposing a heavy public-health burden on families and society. Mesenchymal stem cell(MSC)-derived exosomes, as a novel cell-free therapeutic vector, have emerged as a research hotspot due to their low immunogenicity, no tumorigenic risk, and excellent tissue barrier penetration ability. This review systematically summarizes the core mechanisms of MSC-derived exosomes in regulating immune inflammation, inhibiting apoptosis, and promoting retinal neuroprotection and structural/functional recovery via miRNA and tsRNA, compares the efficacy differences and existing controversies among exosomes from different sources, and outlines the advances in intraocular delivery technologies and engineering modification strategies. Combined with preclinical and clinical data, the current bottlenecks and safety evidence for clinical translation were objectively described. Meanwhile, in view of the heterogeneity among existing studies, this review proposes future directions including standardized preparation and the establishment of efficacy evaluation systems, so as to provide theoretical references for the development of novel therapeutic strategies for retinal degenerative diseases.

Objective: To reveal the molecular mechanism underlying the compatibility of Salvia miltiorrhiza Bge (S. miltiorrhiza, Dan Shen) and C. tinctorius L. (C. tinctorius, Hong Hua) as an herb pair through network pharmacology and subsequent experimental validation. Methods: Network pharmacology was applied to construct an active ingredient-efficacy target-disease protein network to reveal the unique regulation pattern of S. miltiorrhiza and C. tinctorius as herb pair. Molecular docking was used to verify the binding of the components of these herbs and their potential targets. An H9c2 glucose hypoxia model was used to evaluate the efficacy of the components and their synergistic effects, which were evaluated using the combination index. Western blot was performed to detect the protein expression of these targets. Results: Network pharmacology analysis revealed 5 pathways and 8 core targets of S. miltiorrhiza and C. tinctorius in myocardial protection. Five of the core targets were enriched in the hypoxia-inducible factor-1 (HIF-1) signaling pathway. S. miltiorrhiza-C. tinctorius achieved vascular tone mainly by regulating the target genes of the HIF-1 pathway. As an upstream gene of the HIF-1 pathway, STAT3 can be activated by the active ingredients cryptotanshinone (Ctan), salvianolic acid B (Sal. B), and myricetin (Myric). Cell experiments revealed that Myric, Sal. B, and Ctan also exhibited synergistic myocardial protective activity. Molecular docking verified the strong binding of Myric, Sal. B, and Ctan to STAT3. Western blot further showed that the active ingredients synergistically upregulated the protein expression of STAT3. Conclusion The pharmacodynamic transmission analysis revealed that the active ingredients of S. miltiorrhiza and C. tinctorius can synergistically resist ischemia through various targets and pathways. This study provides a methodological reference for interpreting traditional Chinese medicine compatibility.

Objective: To determine the in vitro and in vivo absorption properties of active ingredients of the Chinese medicine, baicalein, to enrich mechanistic understanding of oral drug absorption. Methods: The Biopharmaceutic Classification System (BCS) category was determined using equilibrium solubility, intrinsic dissolution rate, and intestinal permeability to evaluate intestinal absorption mech-anisms of baicalein in rats in vitro. Physiologically based pharmacokinetic (PBPK) model commercial software GastroPlus?was used to predict oral absorption of baicalein in vivo. Results: Based on equilibrium solubility, intrinsic dissolution rate, and permeability values of main absorptive segments in the duodenum, jejunum, and ileum, baicalein was classified as a drug with low solubility and high permeability. Intestinal perfusion with venous sampling (IPVS) revealed that baicalein was extensively metabolized in the body, which corresponded to the low bioavailability predicted by the PBPK model. Further, the PBPK model predicted the key indicators of BCS, leading to reclassification as BCS-II. Predicted values of peak plasma concentration of the drug (Cmax) and area under the curve (AUC) fell within two times of the error of the measured results, highlighting the superior prediction of ab-sorption of baicalein in rats, beagles, and humans. The PBPK model supported in vitro and in vivo evi-dence and provided excellent prediction for this BCS class Ⅱ drug. Conclusion: BCS and PBPK are complementary methods that enable comprehensive research of BCS parameters, intestinal absorption rate, metabolism, prediction of human absorption fraction and bioavailability, simulation of PK, and drug absorption in various intestinal segments across species. This combined approach may facilitate a more comprehensive and accurate analysis of the absorption characteristics of active ingredients of Chinese medicine from in vitro and in vivo perspectives.

Objective To observe the ultrastructure of blood-brain barrier in the nude mouse model of brain me-tastases from lung cancer by transmission electron microscopy using lanthanum nitrate tracing.Methods PC-9 cells (1 × 106/0.1 mL) in logarithmic phase were respectively injected into six nude mice ( model group) selected from eight nude mice randomly via the left ventricle, the other two mice without any treatment as the control group.The general status of the mice was observed after implantation.In the fourth week all the mice were sacrificed and brain tissue samples were taken and prepared for transmission electron microscopic observation using lanthanum nitrate tracing.besides, the lung and brain were removed and stained with HE to detect the presence of tumor metastasis.Results Mice in the model group began to lose weight almost simultaneously in the third week and became moribund slowly, and were all sacrificed at the fourth week when showing clear signs of cachexia.At autopsy, the thoraxes were clear, with normal lungs.Histology showed evidence of brain metastasis in all the six mice.The electron microscopy showed that lathanum nitrate tracer was escaped from the capillaries and diffusely or sparsely distributed in the brain tissues of the model group mice, however lathanum nitrate tracer was still confined in the capillary lumen in the mice of control group.Conclusions The diffuse lathanum nitrate tracer in the brain parenchymal tissue indicates the impairment of blood-brain barrier in the nude mouse model of lung cancer brain metastasis and the formation of these metastases is accompanied with the destruction of blood brain barrier.

Laboratory of electron microscopy is representative of large instruments laboratories in medical research.And the operation and management in this kind of laboratory are different.Case of forty years of operation and management in the medical laboratory of electron microscopy,this paper analyzed and summarized its successful experiences in the research management system,personnel system and the aspect of equipment maintenance management.Provide a management reference for medical research institutions with the laboratory of similar large-scale instruments.

OBJECTIVE: We used the SD rat's bone marrow stromal cells (BMSCs) cultured in vitro to observe the effects of Bugu Mixture on the apoptosis and to explore the molecular biologic mechanism of the treatment of osteoporosis with Bugu Mixture. METHODS: BMSCs were separated from the bones of the extremities of SD rats in vitro. The morphologic changes, the apoptosis cell cycles, the mitochondrion membrane potential changes, and the Bcl-2 and Bax gene expression were observed, and the effects of Bugu Mixture on the course of cell apoptosis were evaluated. RESULTS: The earlier use of Bugu Mixture could decrease the cells blocked in G0/G1 phase, and promote their synthesis of DNA in S phase. The expression of Bcl-2 was higher in the Bugu Mixture group than that in the all-trans retinoic acid (ATRA) induced group, and the expression of Bax was lower in the Bugu Mixture group than that in the ATRA induced group. The mitochondrion membrane potential descended significantly in the Bugu Mixture group than that in the ATRA induced group. CONCLUSION: The mechanism of the treatment of osteoporosis with Bugu Mixture is that the earlier use of Bugu Mixture can decrease the amount of apoptostic cells induced by ATRA, thus promoting the cell mitosis and restraining the apoptosis. It can also act as a protector to Bcl-2 located on the mitochondrion membrane. By preventing the transferring of the Bax protein from cell-plasma to mitochondrion membrane, it takes the advantage of Bcl-2 in forming Bcl-2/Bax homodimer so as to prevent the opening of the permeability transition pore to avoid the changing of mitochondrion membrane potential and the destruction of biosynthesis caused by the mitochondrion release of apoptosis inducing factors and to reach the objective of restraining apoptosis.