Comparative evaluation of periodontal ligament fibroblasts stored in different types of milk: effects on viability and biosynthesis of collagen

Milk remains one of the most frequently recommended solutions for storage of avulsed teeth because it can maintain cell viability and is easily accessible. However, some negative effects of milk on avulsed teeth have been reported, just as the effects of milk on the long‐term functions of cells are not clear. This study aimed to evaluate the effects of different types of milk on the viability, proliferation, and functions of periodontal ligament fibroblasts (PDLF)s in vitro. Human PDLFs were culture‐medium depleted for 5 min and stored in Hanks’ balanced salt solution (HBSS), whole cow's milk, low‐fat cow's milk, or almond milk for 1 h at 25°C. Cell viability and proliferation were assessed using MTT assays. Expression of the genes encoding type I collagen and its modifying enzymes were analyzed using real‐time PCR. Collagen matrix production was evaluated using Picrosirius red polarization. Our results showed the overall efficiency of low‐fat cow's milk in maintaining the viability and proliferation of PDLFs, and in enhancing the process of collagen production. Almond milk storage resulted in the highest rate of PDLF proliferation, and comparable collagen biosynthesis ability to the control. Therefore, besides low‐fat cow's milk, almond milk may potentially be an alternative tooth‐storage medium for PDLF preservation and PDL tissue regeneration.     

Long-term durable repaired cartilage induced by SOX9 in situ with bone marrow-derived mesenchymal stem cells

Background: Microfracture is a common procedure for cartilage repair, but it often produces inferior fibrocartilage. We previously reported that a super positively charged SOX9 (scSOX9) promoted hyaline-like cartilage regeneration by inducing bone marrow derived mesenchymal stem cell differentiation into chondrocytes in vivo. Here we examined the long-term efficacy of cartilage repair induced by microfracture with scSOX9 by assessing the biomechanical property of the repaired cartilage.Methods: A cartilage defect was created at the right femoral trochlear groove in New Zealand female rabbits and microfracture was performed. The scSOX9 protein was administered at the site of microfracture incorporated in a collagen membrane.Results: At 12 and 24 weeks, scSOX9 treatment induced hyaline-like cartilage while collagen-membrane alone induced fibrocartilage and mutant scSOX9-A76E poorly induced cartilage repair. The cartilage matrix in scSOX9-treated group showed highly enriched proteoglycan content. Consistent with the histological feature and the thickness of the repaired cartilage, the mechanical property of scSOX9-induced cartilage was also similar to that of normal cartilage.Conclusion: This long-term in vivo study demonstrated that in combination with microfracture, scSOX9 was able to induce reparative tissue with features of hyaline cartilage which was durable in long-term. This technology has the potential to translate into clinical use for cartilage repair to prevent progression to osteoarthritis.     

不同照射方式下核黄素-A波紫外线兔巩膜胶原交联术对兔巩膜成纤维细胞生物力学特性的影响

目的　研究不同照射方式下核黄素-A波紫外线兔巩膜胶原交联术对兔巩膜成纤维细胞生物力学特性的影响。方法　取健康新西兰大白兔24只，随机将兔平均分为A、B两组，每组选取左眼为实验眼，右眼为对照眼。麻醉后暴露左眼鼻上方巩膜。在该处巩膜滴加5-磷酸核黄素5 min后，用波长为370 nm的紫外线灯照射。A组的照射时间为30 min，能量密度为3.0 mW·cm^-2；B组的照射时间为9 min，能量密度为10.0 mW·cm^-2。照射期间，每2 min滴加1次5-磷酸核黄素溶液，以保持巩膜的湿润。术后60 d，处死实验兔，培养实验眼交联部位及对照眼相应部位的巩膜成纤维细胞，用细胞微管吸吮实验检测巩膜成纤维细胞的杨氏模量、表观黏性。结果　A、B两组实验眼巩膜细胞的杨氏模量、表观黏性均较各自对照眼显著增强，差异均有统计学意义（均为P＜0.05）；而A、B两组实验眼间、及对照眼间巩膜细胞的杨氏模量、表观黏性差异无统计学意义（均为P＞0.05）。以上结果表明，交联术后巩膜细胞的黏弹性发生了明显的变化，黏弹性显著升高。而两种照射方式之间巩膜细胞的黏弹性无显著差异。结论　两种不同的照射方式，均能使巩膜成纤维细胞的生物力学性能发生显著增强，而两种照射方式之间并未见明显的差别。     

Murine type VII collagen distorts outcome in human skin graft mouse model for dystrophic epidermolysis bullosa

Human skin graft mouse models are widely used to investigate and develop therapeutic strategies for the severe generalized form of recessive dystrophic epidermolysis bullosa (RDEB), which is caused by biallelic null mutations in COL7A1 and the complete absence of type VII collagen (C7). Most therapeutic approaches are focused on reintroducing C7. Therefore, C7 and anchoring fibrils are widely used as readouts in therapeutic research with skin graft models. In this study, we investigated the expression pattern of human and murine C7 in a grafting model, in which human skin is reconstituted out of in vitro cultured keratinocytes and fibroblasts. The model revealed that murine C7 was deposited in both human healthy control and RDEB skin grafts. Moreover, we found that murine C7 is able to form anchoring fibrils in human grafts. Therefore, we advocate the use of human‐specific antibodies when assessing the reintroduction of C7 using RDEB skin graft mouse models.     

矿化胶原材料及其在口腔临床中应用研究进展

矿化胶原材料是由胶原和羟基磷灰石组成的新型、有效的骨替代材料，多通过体外仿生学方法合成，模拟天然骨质的化学组成和结构，是一种严格的三维等级序列的多孔材料。因其具有良好的机械性能、生物相容性、骨传导性、骨诱导性和生物降解性等特性，在口腔医学中作为修复材料被广泛应用。文章就矿化胶原材料的性质、分类及其在口腔临床中的应用做一综述，以期为以后科学使用该种材料奠定基础。