毛竹地下茎对创伤的反应

研究了在中国最为广泛栽培的毛竹(Phyllostachys edulis(Cart.)H.de Lehaie)的地下茎的创伤反应。创伤后的第1天,在伤口附近没有明显反应;2d之后,创口附近可以观察到生理反应的代谢物,在后生木质部的导管中以及在基本组织细胞的胞间隙出现粘状物质,这些粘状物质具有果胶特性;创伤后1周,创口附近的筛管及基本组织中的短细胞的细胞壁变成木质化。同时,基本组织中的长细胞的内壁出现新的次生壁的沉积;2周后,创伤反应的组织与未受创伤的组织之间的区别变得更加明显;4周后,一些导管完全充满了粘性物质,但没有观察到侵填体。由于细胞壁的木质化及酚类物质的填充,筛管完全失去了功能。对创伤后6周的材料进行观察的结果表明,其创伤反应的范围不再扩展,在创伤组织与未受伤组织之间的基本组织的细胞壁变得相当厚,从而在两者之间形成一道屏障。毛竹地下茎的这种创伤反应与毛竹竹竿的创伤反应基本上是一致的,只是略有不同。     

Influence of hormones on the functional activity of the regenerating cortex of the enucleated adrenal in situ]

The functional activity of the regenerating cortex was studied in 90 female albino rats (150-200 g) after ablation of the right adrenal and enucleation of the left one. In the period of active growth of the regenerating tissue (10 days after operation) the functional activity of parenchymatous cells was low which is evidenced by poor content of both lipids and "ketosteroids". In parallel with reparation of the adrenal adrenocortical tissue mass the content of physiologically active substances was also restored (20 days after operation). After injection of hydrocortizone (daily dosage 2,5 mg) the growth and differentiation of the bundle-reticular zone in the regenerating area was inhibited. In the glomerular zone the reactions to lipids and "ketosteroids" were mainly similar to those in the glomerular zone of intact adrenal. After injection of ACTH (daily dosage 5 or 10 mg) during 10 days the regenerating area was functionally better developed than in the control since moderately pronounced reactions to "ketosteroids" and lipids appeared in it. Fairly high content of these substances in the regenerated cortex after 20 days of injections of ACTH (10 units) as well as presence of secondary necrobiotic changes pointed to functional overstrain of the newly formed organ.     

Early neurogenesis during caudal spinal cord regeneration in adult Gekko japonicus

Gekko japonicus undergoes dramatic changes in the caudal spinal cord after tail amputation. The amputation induces cell proliferation in the caudal ependymal tube. We performed hematoxylin and eosin staining at different time points in the regeneration process to investigate the morphological characterization of the regenerated appendages. The central canal extended to the blastema post-amputation and the cartilage and muscle tissue appeared 3 weeks after injury. We performed the bromodeoxyuridine (BrdU) incorporation assay to detect proliferating cells during the regeneration process. BrdU positive cells were detected in the peri-central canal. Furthermore, nestin and neuron-specific enolase (NSE) immunocytochemistry were applied to detect neural stem/progenitor cells and neurons. Two weeks after injury, nestin-positive cells undergoing proliferation were located outside of the ependymal tube, and NSE positive cells appeared after 3 weeks of amputation. These data suggest that neurogenesis is an early event during caudal spinal cord regeneration in gecko.     

Electron microscopic observations on the fate of hypertrophic chondrocytes in condylar cartilage of rat mandible

The present study focused on the hypertrophic cell zone and the adjacent region of primary spongiosa in the mandibular condylar cartilage in growing rats (3 to 7 weeks old). In this cartilage, chondrocytes were not arranged in columns, and there was no clear distinction between longitudinal and transverse septum. The hypertrophic chondrocytes were not surrounded entirely by calcified matrix, and capillaries were in close contact with cartilage cells. The staining intensity of the pericellular matrix decreased in the lower hypertrophic cell zone in comparison with that in the upper part of the hypertrophic cell zone. Electron microscopic examinations indicated that the lowest hypertrophic cells contained lysosomes and pinocytotic vesicles. Some hypertrophic chondrocytes appeared to have been released from their lacunae and were observed in the region of the primary spongiosa. Hence it is suggested that the lowest hypertrophic chondrocytes in the rat mandibular condyle do not die but are released from their lacunae into the bone marrow. Further study is needed to determine whether or not these cells do indeed become osteoblasts and/or chondroclasts.     

Transplantation of autologous rabbit BM-derived mesenchymal stromal cells embedded in hyaluronic acid gel sponge into osteochondral defects of the knee

BACKGROUND: Mesenchymal stromal cells (MSC) have the potential to differentiate into distinct mesenchymal tissues including cartilage, suggesting that these cells are an attractive cell source for cartilage tissue engineering approaches. Various methods, such as using hyaluronan-based materials, have been employed to improve transplantation for repair. Our objective was to study the effects of autologous transplantation of rabbit MSC with hyaluronic acid gel sponges into full-thickness osteochondral defects of the knee. METHODS: Rabbit BM-derived MSC were cultured and expanded with fibroblast growth factor (FGF). Specimens were harvested at 4 and 12 weeks after implantation, examined histologically for morphologic features, and stained immunohistochemically for type II collagen and CD44. RESULTS: The regenerated area after autologous transplantation of hyaluronic acid gel sponge loaded with MSC into the osteochondral defect at 12 weeks after surgery showed well-repaired cartilage tissue, resembling the articular cartilage of the surrounding structure, of which the histologic score was significantly better than that of the untreated osteochondral defect. In the regenerated cartilage, type II collagen was found in the pericellular matrix of regenerative chondrocytes, while CD44 expression in the regenerative tissue could not be revealed. DISCUSSION: These data suggest that the autologous transplantation of MSC embedded in hyaluronan-based material may support chondrogenic differentiation and be useful for osteochondral defect repair.     

Muscle ectopic fat deposition contributes to anabolic resistance in obese sarcopenic old rats through eIF2α activation

Obesity and aging are characterized by decreased insulin sensitivity (IS) and muscle protein synthesis. Intramuscular ceramide accumulation has been implicated in insulin resistance during obesity. We aimed to measure IS, muscle ceramide level, protein synthesis, and activation of intracellular signaling pathways involved in translation initiation in male Wistar young (YR, 6‐month) and old (OR, 25‐month) rats receiving a low‐ (LFD) or a high‐fat diet (HFD) for 10 weeks. A corresponding cellular approach using C2C12 myotubes treated with palmitate to induce intracellular ceramide deposition was taken. A decreased ability of adipose tissue to store lipids together with a reduced adipocyte diameter and a development of fibrosis were observed in OR after the HFD. Consequently, OR fed the HFD were insulin resistant, showed a strong increase in intramuscular ceramide level and a decrease in muscle protein synthesis associated with increased eIF2α phosphorylation. The accumulation of intramuscular lipids placed a lipid burden on mitochondria and created a disconnect between metabolic and regulating pathways in skeletal muscles of OR. In C2C12 cells, palmitate‐induced ceramide accumulation was associated with a decreased protein synthesis together with upregulated eIF2α phosphorylation. In conclusion, a reduced ability to expand adipose tissues was found in OR, reflecting a lower lipid buffering capacity. Muscle mitochondrial activity was affected in OR conferring a reduced ability to oxidize fatty acids entering the muscle cell. Hence, OR were more prone to ectopic muscle lipid accumulation than YR, leading to decreased muscle protein anabolism. This metabolic change is a potential therapeutic target to counter sarcopenic obesity.     

Retinoic acid-induced cartilage degradation is caused by cartilage cells

Summary Cartilage cubes, prepared from the proximal epiphyses of neonatal rat humeri and consisting of cartilage tissue only, were cultured in the presence of retinoic acid. The retinoid induced the loss of metachromatic staining with toluidine blue, which correlates with the loss of proteoglycan, followed by tissue degradation processes resulting in a distinct reduction of the cartilage mass. Histologically, fibroblast-like cells appeared within chondrones, indicating a transformation of chondroblasts. Focal tissue degradation was observed after only 2 days. Electron microscopically, the clustered cells within the zone of tissue degradation were rich in various lysosomal structures indicating their lytic activity. Cycloheximide and EDTA completely blocked the retinoic acid effects suggesting that protein synthesis was required and that metalloproteinases may be involved in the degradation processes. In conclusion, with the new test system described here we demonstrated that cartilage cells themselves performed the tissue degradation induced by retinoic acid.     

Angiogenesis after administration of basic fibroblast growth factor induces proliferation and differentiation of mesenchymal stem cells in elastic perichondrium in an in vivo model: mini review of three sequential republication-abridged reports

To date, studies on mesenchymal tissue stem cells (MSCs) in the perichondrium have focused on in vitro analysis, and the dynamics of cartilage regeneration from the perichondrium in vivo remain largely unknown. We have attempted to apply cell and tissue engineering methodology for ear reconstruction using cultured chondrocytes. We hypothesized that by inducing angiogenesis with basic fibroblast growth factor (bFGF), MSCs or cartilage precursor cells would proliferate and differentiate into cartilage in vivo and that the regenerated cartilage would maintain its morphology over an extended period. As a result of a single administration of bFGF to the perichondrium, cartilage tissue formed and proliferated while maintaining its morphology for at least 3 months. By day 3 post bFGF treatment, inflammatory cells, primarily comprising mononuclear cells, migrated to the perichondrial region, and the proliferation of matrix metalloproteinase 1 positive cells peaked. During week 1, the perichondrium thickened and proliferation of vascular endothelial cells was noted, along with an increase in the number of CD44-positive and CD90-positive cartilage MSCs/progenitor cells. Neocartilage was formed after 2 weeks, and hypertrophied mature cartilage was formed and maintained after 3 months. Proliferation of the perichondrium and cartilage was bFGF concentration-dependent and was inhibited by neutralizing antibodies. Angiogenesis induction by bFGF was blocked by the administration of an angiogenesis inhibitor, preventing perichondrium proliferation and neocartilage formation. These results suggested that angiogenesis may be important for the induction and differentiation of MSCs/cartilage precursor cells in vivo, and that morphological changes, once occurring, are maintained.     

Observation on the development of osteochondrosis in young rats

A histopathological study on the development of spontaneous osteochondrosis in the humeral head and medial femoral condyle of rats (6-20 weeks old) was carried out. Findings were classified into three types: normal, transitional and osteochondrotic. In the normal type, the articular cartilage at the caudal region of the humeral head and medial femoral condyle was significantly thinned between 6 and 10 weeks of age (generally the caudal region was thicker than elsewhere at all ages). In the transitional type, the thinning of the cartilage was delayed. In the third type, osteochondrotic lesions were detected in the humeral head from 6 weeks of age and in the medial femoral condyle from 10 weeks of age. The thickness of the cartilage had slightly decreased or had not changed at 20 weeks of age. In the early stages, viable chondrocytes and small destructive foci of cartilage were observed in the basal layer of the thick deep zone. These cells were present in pairs or clusters surrounded by matrix in the large lacunae. Cells and destructive foci were also seen in the surface layer of the deep zone as the rats aged. In the advanced stage, a necrotic area or cleft was formed in the basal layer of the articular cartilage and fibrosis was observed in the subchondral bone.     

Comparative Studies on Differentiation of Regenerated Tissue in Broussonetia papyrifera

This paper describes the differentiation process of regenerated tissue after ordinary girdling or after removal of a section of xylem from the stem, and the disparity in differentiation of the regenerated tissues after being differently treateds in Broussonetia papyrifera. After ordinary girdling for 3–4 weeks, new bark regenerated in the xylem. During the process of rind' formation, many specks of meristematic tissue were formed in the callus, from which vascular tissue clusters were developed. In addition, the new periderm appeared almost at the same time as the new vascular cambium was seen. When a section of xylem was removed from the stem, numerous calli developed rapidly on the inner surface of the bark. Meanwhile, the vascular cambium appeared in the immature phloem. Soon after, discontinued meristematic tissue bands also occurred in the callus. These meristematic tissues then connected with each other to form a concave oblate cambial ring which developed xylem inward and phloem outward. About 2–3 weeks later, the concave oblate trunk grew lengthwisely connecting with the upper anct lower portions of the normal stem. By then, the tree continued to grow. The inner surface tissue of the bark, after the xylem was removed, differentiated about one week earlier than the tissue on the surface of the xylem after girdling.     

Bone formation following intrarenal transplantation of isolated murine chondrocytes: chondrocyte-bone cell transdifferentiation?

Isolated syngeneic epiphyseal chondrocytes transplanted into a muscle formed cartilage in which matrix resorption and endochondral ossification began at the end of the second week after transplantation. After 56 days cartilage was converted into an ossicle. In 7-day-old intrarenal transplants, epiphyseal chondrocytes formed nodules of cartilage. In 10-day-old transplants, islands of bone appeared. Slight resorption of cartilage was first noted in 14-day-old transplants of chondrocytes. After eight weeks, transplants contained mainly bone. Intramuscularly transplanted rib chondrocytes formed cartilage which did not ossify. Nevertheless, bone islands appeared in intrarenal transplants of rib chondrocytes. Bone was not formed in allogeneic intrarenal transplants of epiphyseal or rib chondrocytes, but appeared in such transplants in animals immunosuppressed by anti-thymocyte serum and procarbazine. When spleen cells from animals immunized with allogeneic chondrocytes were transferred to immunosuppressed chondrocyte recipients two weeks after intrarenal chondrocyte transplantation, the majority of osteocytes in bone islands was dead. On the other hand, endochondral bone formed in intramuscular transplants of allogenic epiphyseal chondrocytes in immunosuppressed recipients was not damaged by sensitized spleen cells. This suggested that bone in 10- to 14-day-old intrarenal transplants of chondrocytes arose from injected cells and not by induction. To see whether bone was formed by chondrocytes or by some cells contaminating the chondrocyte suspension, the superficial layer of rib cartilage was removed by collagenase digestion and only more central chondrocytes were used for transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)     

ADIPOSE TISSUE : Morphological Changes Associated with Lipid Mobilization

Morphological changes associated with mobilization of lipid were studied in epididymal adipose tissue from fasted and from alloxan diabetic rats. In both groups of animals a decrease in lipid content was accompanied by the formation of complex frond-like cytoplasmic processes and of loops and folds of basement membrane which extended from cell surfaces. These changes, evident after 1 day of fasting, increased in magnitude with increasing weight loss. As the lipid content of the cell decreased further, lipid-cytoplasmic interfaces became irregular and convoluted. Cytoplasmic microvesicles were prominent and appeared to be greatly increased in number. Rosette-like structures composed of microvesicles were observed in both lipid-depleted fat cells and endothelium. The interpretation of these changes and their physiological significance are discussed in terms of the physical and chemical properties of lipids and lipid metabolism. It is postulated that microvesicles may represent the mechanism of transport of free fatty acids in fat cells and in endothelium. Hypotheses are proposed and illustrated schematically for the mode of formation of microvesicular rosettes, for the mobilization and uptake of lipids by fat cells, and for the transport of lipids through endothelium.     

Morphological and biomechanical evaluations of neocartilage from the repair of full-thickness articular cartilage defects using rib perichondrium autografts: a long-term study

Neocartilage regenerated from rib perichondrium autografts implanted into full thickness cartilage defects made in the femoral condyle of rabbit knees were evaluated for periods up to 1 yr. Two postoperative treatment effects were studied, one with ad lib. caged activity (CAGE) and the other with the operated knee placed on a continuous passive motion machine for 2 weeks (8 h day-1 for 5 days week-1) followed by caged activity (PM). Animals were sacrificed at 6, 12, 26 and 52 weeks after surgery. The neocartilage was evaluated histologically and biomechanically and compared with the contralateral unoperated side. Visually, the neocartilage appeared to have an appearance similar to that of surrounding cartilage at 52 weeks, with an excellent degree of confluence with the neighboring tissue. The newly grown tissues were morphologically similar to normal hyaline articular cartilage. The dynamic shear moduli for the neocartilage from both the CAGE and PM groups significantly increased with postoperative healing time (p less than 0.05). However, there was no statistical difference between the two treatment modalities (p greater than 0.10), indicating that the passive motion did not enhance the long-term repair of the cartilage defect. These results support our hypothesis that neocartilage regenerated from perichondrial autograft remains intact over time.     

Strong hyaluronan expression in the full-thickness rat articular cartilage repair tissue

Articular cartilage lesions have a poor capacity to regenerate. In full-depth articular cartilage defects, the repair process involves an ingrowth of mesenchymal cells from the bone marrow to the injured area, and these cells attempt to restore the lesion with cartilage-like repair tissue. In this study, we investigated histologically the distribution of hyaluronan in the rat repair tissue in relation to other glycosaminoglycans. Full-depth lesions were drilled to the weight-bearing region of rat medical femoral condyle. The rats were divided into two groups: intermittent active motion (IAM) and running training (RT) groups. In the RT group, programmed exercise was started 1 week after surgery, while the rats in the IAM group could move freely in their cages. The lesions were investigated 4 and 8 weeks after the surgery. Semiquantitative histological grading showed no significant differences in the repair between the groups. In normal articular cartilage, hyaluronan was stained mainly around chondrocytes. During repair, strong hyaluronan staining was observed in loose mesenchymal tissue, while in the repair area undergoing endochondral ossification, hyaluronan was intensively stained mainly around the hypertrophic chondrocytes. Remarkably strong staining for hyaluronan was noticed in areas of apparent mesenchymal progenitor cell invasion, the areas being simultaneously devoid of staining for keratan sulphate. In conclusion, hyaluronan is strongly expressed in the early cartilage repair tissue, and its staining intensity and distribution shows very sensitively abnormal articular cartilage structure.     

Studies on glycosaminoglycans of regenerating rabbit ear cartilage

Cartilage regeneration in the adult rabbit ear was examined with respect to glycosaminoglycan (GAG) synthesis at various stages of the regeneration process. Increased hyaluronic acid and chondroitin sulfate synthesis was first seen 31 days after wounding, when a metachromatic cartilage matrix could be distinguished from blastemal cells. Analysis of cartilage and the overlying skin separately showed that 90% of the labeled chondroitin sulfate was found in the cartilage being regenerated. DEAE-cellulose chromatography of GAG preparations from 35-day regenerating cartilages showed hyaluronic acid and chondroitin sulfate peaks eluting in the same position as those isolated from normal cartilages. The identity of the hyaluronic acid and chondroitin sulfate peaks was confirmed by their susceptibility to Streptomyces hyaluronidase and chondroitinase ABC, respectively. Although the degree of sulfation in normal and regenerated cartilages was similar, the ratio of chondroitin 6-sulfate to chondroitin 4-sulfate was increased in regenerated cartilages. GAG preparations from unlabeled cartilages were digested with chondroitinase ABC and the disaccharide digestive products were identified and quantitiated. Normal cartilage had a $\text{Δ}\text{Di-6S}\text{Δ}\text{Di-4S}$ ratio of 0.27; the same ratio for the regenerated cartilage was 1.58.     

Retention of labelled DNA precursor by murine cells after a single administration of tritium labelled thymidine

The central zone of the rat lens epithelium, extending half way from the centre to the periphery of a whole mount preparation, normally has less than 1% of the cells in the cell cycle at any given time. Mechanical wounding initiates a burst of proliferation in the central zone. DNA synthesis begins 14 hr after wounding followed by mitosis 10 hr later. When [3H]TdR was applied at 2 hr prior to S phase, some moderately heavy and some light labelling was observed after the onset of S phase. When [3H]TdR was applied 5 hr before S phase (9 hr after wounding), all the cells were lightly labelled. Only small amounts of the label were available to these cells 5 hr after application. It is significant that there was labelling in this group because it indicates the persistence of relatively small intracellular pools of [3H]TdR for several hours after the initial 'pulse' labelling of cells. Determinations of the duration of S phase were based on the assumption that pulse labelling may be affected by the persistence of the pools of [3H]TdR and consequent light labelling of the cells.     

Lipids at the stages of early osteogenesis in human long tubular bones

In 240 long tubular bone anlagen (LTBA) of extremities in 40 human embryos and prefetuses at the age of 6-12 weeks of the prenatal development the investigation has been performed concerning localization, dynamics of contents and spectrum of neutral lipids and phospholipids. Lipids are stained with Sudan III and IV, phospholipids-with Sudan black with corresponding control extractive methods and quantitative estimation of these substances values. The material for electron microscopical investigation of the lipids is treated according to the method, that preserves their safety. The spectrum of lipids and phospholipids in the LTBA is studied by means of the thin layered chromatography method. The data of the histochemical investigation and chromatography demonstrate decreasing contents of neutral lipids with the gradient from the zone of the preserved cartilage up to the ossification zone of the epiphyseal cartilage of the LTBA in the human embryos and prefetuses. Increased concentration of phospholipids and complication of their spectrum is noted in the areas of intensive deposits of calcium salts. An essential role of the substance of lipid origin is supposed in ossification and mineralization of the human LTBA.     

Differentiation of transplanted mesenchymal stem cells in a large osteochondral defect in rabbit

BACKGROUND: Although accumulating evidence shows that mesenchymal stem cells (MSC) are a promising cell source for articular cartilage repair, the fate of transplanted MSC has not been extensively studied. METHODS: To monitor their persistence and differentiation, we labeled uninduced MSC with a fluorescent dye, PKH26, and transplanted them, in a poly-glycolic-acid scaffold, to full-thickness defects made in the weight-bearing area of rabbit femoral trochleae with hyaluronate sheets. The fate of the labeled cells was monitored for up to 8 weeks. RESULTS: Two weeks after transplantation, immature cartilage containing collagen type II had formed. By 8 weeks, this cartilage had thinned and immunolabeling for collagen type II gradually disappeared from the basal region, which became positive for collagen type I. Most chondrocytes within the regenerated cartilage were PKH26-positive and, therefore, derived from transplanted MSC, whereas osteoblasts within the regenerated bone were a mixture of donor- and host-derived cells. The thickness of the cartilage became thinner up to 8 weeks and then remained stable up to 42 weeks after surgery. DISCUSSION: These results showed that uninduced MSC were able to survive osteochondral defects and differentiated according to the environment, making a major contribution to initial cartilage formation and a partial contribution to bone regeneration.     

In vivo studies of the relationship between the activation of lipid metabolism, postirradiation bone marrow cell proliferation and radioresistance of mice

The effect of adaptation to intermittent feeding on the in vivo biosynthesis of fatty acids and total lipids in the epididymal adipose tissue, the liver and the bone marrow was studied in adult male mice (CBA/JPh x C57BL@10 ScSnPh)F1. At the same time the effects of the same experimental stimulus on the rate of regeneration (proliferation) of bone marrow cells after sublethal irradiation of animals and on the overall radioresistance of mice expressed as 30 days survival after whole-body gamma irradiation were determined. Intermittent feeding in mice has been shown to have a significant effect on the biosynthesis of fatty acids and total lipids in all the tissues studied, including bone marrow cells, the intensity of the effect being closely dependent on the duration of the experimental stimulus. Maximum stimulation of lipogenesis during realimentation was observed approximately within 1 week of adaptation, with a reduction of the metabolic responses thereafter. The intensity of bone marrow cell proliferation in mice irradiated in the realimentation phase was inversely proportional to the preirradiation degree of biosynthesis of fatty acids and total lipids: in a period of lower lipogenetic capacity of cells in the tissue studied (around the weeks 2-5 of adaptation) an increase in the regeneration potential of bone marrow cells was observed together with increased radioresistance of the mice. During the 1-week of adaptation the opposite proved to be the case. Attention is drawn to the possible participation of prostaglandins and lipid peroxides in the responses observed.