Objective To prepare porcine acellular dermal matrix(PADM) without cytotoxicity,to evaluate its biological safety,and investigate its end result in vivo.Methods A piece of porcine split-thickness skin of 0.3-0.4mm was obtained,the epidermis was removed by hypertonic saline immersion,and then the skin was immersed in sodium hydroxide solution,and dermal cells were removed by shaking water bath at normal temperature to harvest PADM.After cross-linking and sterilization,bacteria and porcine virus were examined in the PADM.The PADM were embedded beneath the Sprague-Dawley(SD) rat's skin,and then the general and histological changes were observed after transplantation.Result The obtained PADM was soft and elastic,easy to be moulded,and convenient for operation.No cellular component was found in PADM,the collagen was regularly arranged and elastic fibers were abundant.Bacteria and virus examination of all specimens was negative.No immunologic rejection of PADM was found after being embedded beneath the skin of SD rat.The PADM adhered to the wound firmly,and it was difficult to detach 3 weeks after implantation,and the general structures of PADM beneath rat skin were discernible 24 weeks after implantation.The PADM was infiltrated by inflammatory cells in the early stage,fibroblasts and capillary vessels increased in number along with the time,and collagen fibers gradually gained a regular and compact arrangement in PADM.Conclusions The PADM prepared by hypertonic saline/sodium hydroxide method is a simple preparation process,and there is no cytotoxicity.It has a high biological safety and can be used as dermal scaffold with long-term existence in vivo.

To adapt the requirement of Chinese education development, and to abandon the defects of two semester system, such as too-long semester, inflexible curriculum, and restricting personality devel-opment of students, Xi'an Jiaotong University has performed semester reform for reforming the contents and methods of the teaching, promoting the innovation ability of students, and improving the quality of the scholastic education since 2013. In the current study, we have attempted to demonstrate the benefits of the semester reform for promoting the innovation ability of students, and to reveal the active role of the semester reform through comparing the presentation of medical undergraduate students in the national competition of innovation training for medical undergraduate students. Overall, the results of our analysis have supported the semester reform, and provided the reference information for the semester reforms of Chinese universities.

Lipid nanoparticle (LNP)-based drug delivery systems have become the most clinically advanced non-viral delivery technology. LNPs can encapsulate and deliver a wide variety of bioactive agents, including the small molecule drugs, proteins and peptides, and nucleic acids. However, as the physicochemical properties of small- and macromolecular cargos can vary drastically, every LNP carrier system needs to be carefully tailored in order to deliver the cargo molecules in a safe and efficient manner. Our group applied the combinatorial library synthesis approach and in vitro and in vivo screening strategy for the development of LNP delivery systems for drug delivery. In this Review, we highlight our recent progress in the design, synthesis, characterization, evaluation, and optimization of combinatorial LNPs with novel structures and properties for the delivery of small- and macromolecular therapeutics both in vitro and in vivo. These delivery systems have enormous potentials for cancer therapy, antimicrobial applications, gene silencing, genome editing, and more. We also discuss the key challenges to the mechanistic study and clinical translation of new LNP-enabled therapeutics.

Microglia are involved in the inflammatory response and retinal ganglion cell damage in glaucoma. Here, we investigated how microglia proliferate and migrate in a mouse model of chronic ocular hypertension (COH). In COH retinas, the microglial proliferation that occurred was inhibited by the P2X7 receptor (P2X7R) blocker BBG or P2X7R knockout, but not by the P2X4R blocker 5-BDBD. Treatment of primary cultured microglia with BzATP, a P2X7R agonist, mimicked the effects of cell proliferation and migration in COH retinas through the intracellular MEK/ERK signaling pathway. Transwell migration assays showed that the P2X4R agonist CTP induced microglial migration, which was completely blocked by 5-BDBD. In vivo and in vitro experiments demonstrated that ATP, released from activated Müller cells through connexin43 hemichannels, acted on P2X7R to induce microglial proliferation, and acted on P2X4R/P2X7R (mainly P2X4R) to induce microglial migration. Our results suggest that inhibiting the interaction of Müller cells and microglia may attenuate microglial proliferation and migration in glaucoma.
Adenosine Triphosphate/pharmacology* ; Animals ; Cell Proliferation ; Glaucoma/metabolism* ; Mice ; Microglia/metabolism* ; Receptors, Purinergic P2X4/metabolism* ; Receptors, Purinergic P2X7/metabolism* ; Retinal Ganglion Cells/metabolism*