Interaction between bovine collagen and glycolic acid peeling: A proposal of a new protocol

For the past 10 years the alfa-hydroxyacids and the bovine collagen injection have been used for peeling and the correction of multiple skin diseases. Until now, such progressive achievement has occurred in separate parallels just like the indications that have been held distinct. However, the studies carried out in order to clarify the mechanical action of the two substances have shown a common and fundamental denominator: the stimulation of synthesis of the new collagen in the patient's skin. On the basis of these results and the existence of common clinical indications of the use of glycolic acid and collagen, the authors have worked out a protocol involving a combined and contemporary application in progressive steps. They developed the rationales of such protocol and analyzed the results of its application on a number of carefully selected patients for a clinical comparison and on a sample of rats for a histological comparison. They have concluded that the contemporary use of glycolic acid and bovine collagen is a simple and safe method whose synergy action leads to more intense and long-lasting effects than the ones observed in the isolated application of the two substances. The authors have also obtained interesting and significant histological results.     

Morphologic characterization of osteoblast-like cell cultures isolated from newborn rat calvaria

Summary Two methods for harvesting osteoblast-like cell populations from newborn (10 days) rat calvaria were compared. The first one consisted in culturing the periosteum-free bones and then trypsinizing the cells on the bone surface. The second one involved the migration of the osteoblasts on glass fragments before trypsinization. Since the plating efficiency, the proportion of alkaline phosphatase-positive cells, the population doubling time, and the calcium deposition were more adequate, the second method was used to further characterize the behavior of the cultures. During the first week of culture, the cells featured shapes similar to those observedin vivo on the surface of periosteum-free calvaria. They formed multilayers and, in the presence of ascorbic acid, synthetized an organic matrix containing exclusively type I collagen. Later, small amounts of type III collagen appeared. The cells were embedded in the matrix and progressively acquired the morphologic phenotype of osteocyte-like cells. The matrix mineralized in the presence of β-glycerophosphate. The technique of dropinoculation (high concentration of cells in a small volume of medium) promoted the multilayer formation and the achievement of large mineralized plates (about 1 cm²) in 3 weeks of culture.     

胶原材料在药物缓释和组织工程中的研究进展

目的介绍胶原材料在药物缓释和组织工程中的研究新进展. 方法广泛查阅近年相关文献并进行回顾与综合分析. 结果胶原材料在药物缓释与组织工程中的应用研究已取得明显进展,胶原材料已成为组织工程研究的热点之一.一些胶原基质新型药物缓释系统和新型组织工程材料已进入临床论证阶段,将促进胶原材料在组织修复中的临床应用. 结论胶原材料在药物缓释、尤其是组织工程领域具有广阔的应用前景.除将胶原适当交联处理或与其它天然或合成高分子复合外,今后的研究中还应注重利用化学修饰改善胶原性能,通过将性质不同的支链接枝到胶原大分子上,赋予胶原新的特性,从而研制出新一代组织工程材料.     

Disaggregation of bone into crystals

Summary The sizes, shapes, and organizational states of the crystals in bone are studied by systematic disaggregation of the mineral phase. This is achieved by oxidizing the organic phase with sodium hypochlorite, dispersing the resultant particles by sonication, and separating the crystal aggregates from the crystal monomers by gravity setting in ethanol. Six different bones are compared. Bones in which crystals are intimately associated with the collagen fibrils mostly disaggregate into crystal monomers. In dense bones, where the crystals are mostly located between fibrils, they tend to persist as “fused” aggregates. All the crystals are tabular or plate-shaped. In bones in which the majority of crystals are associated with the collagen fibrils, just less than 90% of the crystals are shorter than about 450 ? in length. Their widths are on the average about 250 ?, almost an order of magnitude larger than the diameters of individual gap regions within the collagen fibril. The notion that one crystal is located in one gap region is therefore untenable and a reevaluation of the relations between collagen and mineral in bone is necessary.     

戊二醛交联提高胶原/壳聚糖真皮支架抗细胞收缩能力的研究

目的 应用交联处理的胶原支架,来减缓其降解过多、易收缩变形、机械性能不足等缺点.方法 采用冷冻-冻干法构建胶原/壳聚糖多孔支架,并通过戊二醛交联构建具有良好抗细胞收缩稳定性和细胞相容性的胶原支架.通过测定不同培养时间各类支架的尺寸变化,研究了戊二醛交联对支架抗细胞收缩能力的影响.结果 戊二醛交联后的胶原/壳聚糖支架未见明显收缩,其细胞活性也始终高于干热交联支架.结论 戊二醛能有效地提高胶原基支架的抗细胞收缩能力,并保持其良好的生物相容性.     

脂肪干细胞/Ⅰ型胶原凝胶复合体的构建及其体内外成骨分化研究

目的探讨利用脂肪干细胞与Ⅰ型胶原凝胶复合构建新型骨组织工程复合体的可行性并对其体内外成骨分化情况进行分析。方法取3月龄日本大耳白兔肩胛部皮下脂肪，Ⅰ型胶原酶消化获得细胞，于体外依次进行骨、软骨、脂肪多向诱导分化鉴定；取第3代细胞与Ⅰ型胶原凝胶复合，于成骨诱导条件下体外培养，相差显微镜、扫描电镜观察复合情况并对其碱性磷酸酶、细胞外基质矿化程度进行检测，同时设立单层贴壁培养细胞作为对照（n=4）；两周后移植于裸鼠皮下，12周后处死动物，依次行放射学、组织学检测观察成骨情况（n=3）。结果（1）所获细胞具备骨、软骨、脂肪多向分化潜能，为多能干细胞。（2）形态学观察显示脂肪干细胞呈三维立体生长状态，均匀、高密度悬浮于Ⅰ型胶原凝胶中。在体外成骨诱导条件下，其碱性磷酸酶活性以及外基质矿化程度均显著高于单层贴壁培养细胞（P〈0．01，n=4）。（3）于裸鼠皮下移植12周后，放射学、组织学检测显示脂肪干细胞．Ⅰ型胶原凝胶复合体成骨明显（n=3）。结论（1）IⅠ型胶原凝胶可显著促进脂肪干细胞的成骨分化。（2）作为一种新型的骨组织工程复合物，脂肪干细胞-Ⅰ型胶原凝胶复合体可应用于骨组织工程，特别是腔隙性骨缺损的修复过程。     

明胶降解物对大鼠真皮成纤维细胞增殖及Ⅰ型胶原蛋白分泌的影响

目的 探讨组织工程心瓣膜常用人工基质材料--明胶发生降解后的产物对大鼠真皮成纤维细胞增殖及Ⅰ型胶原蛋白分泌的影响. 方法 利用酶组合技术制备明胶降解物（gelatin hydrolysate, GH）,采用超滤的方法分离出低分子量明胶降解物组分（gelatin hydrolysate fraction, GHF）,用于5只SD大鼠真皮成纤维细胞的体外培养.采用CCK-8活细胞计数试剂盒（Cell Counting Kit-8）检测细胞的增殖情况,ELISA试剂盒检测细胞I型胶原蛋白的分泌情况. 结果 ①GHF对细胞增殖作用的浓度效应：在0.125～1.0 mg/ml浓度范围内,GHF对细胞的促增殖作用呈现先增强后减弱的趋势,在0.25 mg/ml时,细胞增殖率最大,达到（47.54±16.35）%;②GH与GHF对细胞增殖影响比较：GH与GHF均具有促进细胞增殖的作用,且在浓度为0.25 mg/ml时,促细胞增殖作用无显著差异[（27.04±15.21）% vs （39.22±15.55）%, P=0.177];③GH与GHF对细胞分泌Ⅰ型胶原蛋白影响比较：GHF组第3天时Ⅰ型胶原分泌量为（28.06±5.60）pg/105,与空白对照的（18.24±4.52）pg/105相比,有显著差异（P=0.006）,而GH组直至第6天时Ⅰ型胶原蛋白分泌量,与空白对照相比,无统计学意义（P=0.103）. 结论 分子量大小不同的明胶降解物GH与GHF均具有促进大鼠真皮成纤维细胞增殖的作用,且分子量较小的GHF还具有促进细胞I型胶原分泌的功能.     

丹参在抑制兔唇创口瘢痕增生中的作用

选用50只新西兰白兔,2只处死后取上唇组织作为病理对照,48只采用Millard’s法修复上唇裂隙,拆线后随机分为实验组、溶媒组和对照组3组,每组16只。实验组每天涂擦复方丹参膏2次,溶媒组每日涂擦溶媒膏二次,对照组不作任何处理。分别在术后0d、7d、15d、21d、30d、60d、90d测量上唇瘢痕的体积变化,并在7d、30d、60d时每组分别处死2只,90d后全部处死,取上唇瘢痕组织在光镜和电镜下观察组织病理学变化。组织学观察显示丹参可抑制成纤维细胞增殖,影响胶原蛋白合成,使胶原纤维重排和降解,从而减轻瘢痕增生。