Hydroxyapatite-Coated Small Intestinal Submucosa Membranes Enhanced Periodontal Tissue Regeneration through Immunomodulation and Osteogenesis via BMP-2/Smad Signaling Pathway.

Periodontitis, a chronic infection causing periodontal tissue loss, may be effectively addressed with in situ tissue engineering. Small intestinal submucosa (SIS) offers exceptional biocompatibility and biodegradability but lacks sufficient osteoconductive and osteoinductive properties. This study develops and characterizes SIS coated with hydroxyapatite (SIS-HA) and gelatin methacrylate hydroxyapatite (SIS-Gel-HA) using biomineralization and chemical crosslinking. The impact on periodontal tissue regeneration is assessed by evaluating macrophage immune response and osteogenic differentiation potential of periodontal ligament stem cells (PDLSCs) in vitro and rat periodontal defects in vivo. The jejunum segment, with the highest collagen type I content, is optimal for SIS preparation. SIS retains collagen fiber structure and bioactive factors. Calcium content is 2.21% in SIS-HA and 2.45% in SIS-Gel-HA, with no significant differences in hydrophilicity, physicochemical properties, protein composition, or biocompatibility among SIS, SIS-HA, SIS-Gel, and SIS-Gel-HA. SIS is found to upregulate M2 marker expression, both SIS-HA and SIS-Gel-HA enhance the osteogenic differentiation of PDLSCs through the BMP-2/Smad signaling pathway, and SIS-HA demonstrates superior in vitro osteogenic activity. In vivo, SIS-HA and SIS-Gel-HA yield denser, more mature bones with the highest BMP-2 and Smad expression. SIS-HA and SIS-Gel-HA demonstrate enhanced immunity-osteogenesis coupling, representing a promising periodontal tissue regeneration approach.

Biomimetic Mineralized Hydroxyapatite-Fish-Scale Collagen/Chitosan Nanofibrous Membranes Promote Osteogenesis for Periodontal Tissue Regeneration.

Commercial mammalian collagen-based membranes used for guided tissue regeneration (GTR) in periodontal defect repair still face significant challenges, including ethical concerns, cost-effectiveness, and limited capacity for periodontal bone regeneration. Herein, an enhanced biomimetic mineralized hydroxyapatite (HAp)-fish-scale collagen (FCOL)/chitosan (CS) nanofibrous membrane was developed. Specifically, eco-friendly and biocompatible collagen extracted from grass carp fish scales was co-electrospun with CS to produce a biomimetic extracellular matrix membrane. An enhanced biomimetic mineralized HAp coating provided abundant active calcium and phosphate sites, which promoted cell osteogenic differentiation, and showed greater in vivo absorption. In vitro experiments demonstrated that the HAp-FCOL/CS membranes exhibited desirable properties with no cytotoxicity, provided a mimetic microenvironment for stem cell recruitment, and induced periodontal ligament cell osteogenic differentiation. In rat periodontal defects, HAp-FCOL/CS membranes significantly promoted new periodontal bone formation and regeneration. The results of this study indicate that low-cost, eco-friendly, and biomimetic HAp-FCOL/CS membranes could be promising alternatives to GTR membranes for periodontal regeneration in the clinic.

Advances of Hydrogel Therapy in Periodontal Regeneration-A Materials Perspective Review.

Hydrogel, a functional polymer material, has emerged as a promising technology for therapies for periodontal diseases. It has the potential to mimic the extracellular matrix and provide suitable attachment sites and growth environments for periodontal cells, with high biocompatibility, water retention, and slow release. In this paper, we have summarized the main components of hydrogel in periodontal tissue regeneration and have discussed the primary construction strategies of hydrogels as a reference for future work. Hydrogels provide an ideal microenvironment for cells and play a significant role in periodontal tissue engineering. The development of intelligent and multifunctional hydrogels for periodontal tissue regeneration is essential for future research.

Development of male gametophyte of Larix leptolepis Gord. with emphasis on diffuse stage of meiosis.

A basic developmental framework of the Larix leptolepis Gord male gametophyte is presented in detail by squashing technique. The duration of the meiosis stage was more than 6 months, and included a long diffuse stage during winter. This long duration of the diffuse appearance of the diplotene stage makes L. leptolepis a unique suitable experimental material for studying the structure and function of the diffuse stage of meiosis. In particular, the processes of desynapsing and unpairing, which so far have received little attention, can be examined in detail. In L. leptolepis, the chromosomes undergo a dramatic structural reorganization during the diffuse diplotene stage. Based on the clearly visible differences in chromosome morphology, the diffuse diplotene stage was divided into four periods with suggested nomenclature as follows: schizonema, pre-diffuse diplotene, diffuse diplotene and post-diffuse diplotene. Both simultaneous and successive microsporogenesis were observed within L. leptolepis, and there was no strict relationship between the microsporogenesis types and the tetrad configurations, which are strongly influenced by spindle orientation, especially during meiosis II. The mature pollen grain at pollination consists of five cells aligned in an axial row. The prothallial cells cannot be regarded as senescent cells because they remain capable of division.

Physical mapping of rDNA in Dendranthema nankingense and its close related species by fluorescent in situ hybridization.

Distribution of 18S-26S rDNA on the chromosomes of Dendranthema nankingense and its two close-related species D. nankingense and D. lavendulifolium was studied by fluorescent in situ hybridization with a JHD 2-15A DNA clone. Six rDNA loci were found in D. nankingense, eight in D. lavendulifolium, and twelve in D. indicum. The rDNA loci number and pattern were applied to analyze the phylogenetic relationship of the three closely related species.