生长分化因子-5诱导小鼠骨髓基质干细胞向软骨分化过程中对缝隙连接蛋白43表达的影响

目的探讨生长分化因子-5(GDF-5)在小鼠骨髓基质干细胞(BMSCs)向软骨分化过程中对缝隙连接蛋白43(Cx43)表达的影响。方法体外培养小鼠BMSCs,贴壁细胞传代,取第3代细胞,加入地塞米松、VitC、胰岛素和GDF-5诱导培养,72 h后免疫细胞化学和阿尔辛蓝染色分别检测软骨细胞特异性Ⅱ型胶原和蛋白多糖的表达；在诱导24、48和72 h后进行如下检测：MTT法测定GDF-5对小鼠BMSCs增殖的影响；RT-PCR、Western blotting和免疫细胞化学法检测GDF-5对Cx43蛋白表达的影响。结果MTT结果显示不同时间GDF-5对小鼠BMSCs的增殖无影响；RT-PCR、Western blotting和免疫细胞化学结果表明诱导后不同时间均有Cx43 mRNA和蛋白的表达；诱导72 h免疫细胞化学显示有Ⅱ型胶原蛋白的表达,阿尔辛蓝染色阳性,有蛋白多糖基质的分泌。结论GDF-5可以通过上调缝隙连接蛋白Cx43的表达来促进小鼠BM- SCs向软骨方向的分化。     

胚泡着床期碱性成纤维细胞生长因子在小鼠子宫内膜的转录和表达

为进一步阐明碱性成纤维细胞生长因子 (b FGF)在胚泡着床过程中的生物学作用。采用昆明小鼠 3 0只 ,随机分为 5组 ,分别于受精后 4～ 8天处死孕鼠。应用原位杂交和免疫组织化学的方法 ,检测了不同孕期的子宫内膜 b FGF的转录和表达状况。结果 :子宫内膜多种细胞可产生 b FGF,受精后第 4～ 5天 ,b FGF表达仅限于子宫腔上皮和腺上皮 ,b FGF在蜕膜细胞的转录则最早出现于受精的第 5天 ,随胚泡植入的进程 ,蜕膜细胞b FGF的转录和表达明显增加 ,但在胚泡着床部位周围蜕膜细胞转录和表达由有至无。表明 b FGF通过自或旁分泌的方式参与调节胚泡着床的生理过程     

Fibroblast growth factor expression in the postnatal growth plate

Fibroblast growth factor (FGF) signaling is essential for endochondral bone formation. Mutations cause skeletal dysplasias including achondroplasia, the most common human skeletal dysplasia. Most previous work in this area has focused on embryonic chondrogenesis. To explore the role of FGF signaling in the postnatal growth plate, we quantitated expression of FGFs and FGF receptors (FGFRs) and examined both their spatial and temporal regulation. Toward this aim, rat proximal tibial growth plates and surrounding tissues were microdissected, and specific mRNAs were quantitated by real-time RT-PCR. To assess the FGF system without bias, we first screened for expression of all known FGFs and major FGFR isoforms. Perichondrium expressed FGFs 1, 2, 6, 7, 9, and 18 and, at lower levels, FGFs 21 and 22. Growth plate expressed FGFs 2, 7, 18, and 22. Perichondrial expression was generally greater than growth plate expression, supporting the concept that perichondrial FGFs regulate growth plate chondrogenesis. Nevertheless, FGFs synthesized by growth plate chondrocytes may be physiologically important because of their proximity to target receptors. In growth plate, we found expression of FGFRs 1, 2, and 3, primarily, but not exclusively, the c isoforms. FGFRs 1 and 3, thought to negatively regulate chondrogenesis, were expressed at greater levels and at later stages of chondrocyte differentiation, with FGFR1 upregulated in the hypertrophic zone and FGFR3 upregulated in both proliferative and hypertrophic zones. In contrast, FGFRs 2 and 4, putative positive regulators, were expressed at earlier stages of differentiation, with FGFR2 upregulated in the resting zone and FGFR4 in the resting and proliferative zones. FGFRL1, a presumed decoy receptor, was expressed in the resting zone. With increasing age and decreasing growth velocity, FGFR2 and 4 expression was downregulated in proliferative zone. Perichondrial FGF1, FGF7, FGF18, and FGF22 were upregulated. In summary, we have analyzed the expression of all known FGFs and FGFRs in the postnatal growth plate using a method that is quantitative and highly sensitive. This approach identified ligands and receptors not previously known to be expressed in growth plate and revealed a complex pattern of spatial regulation of FGFs and FGFRs in the different zones of the growth plate. We also found temporal changes in FGF and FGFR expression which may contribute to growth plate senescence and thus help determine the size of the adult skeleton.     

人胎肺成纤维细胞对小鼠胚胎干细胞生长支持作用的研究

目的探讨人胎肺成纤维细胞（hELF）作为饲养层支持小鼠胚胎干细胞（ES）的生长及维持ES细胞的未分化状态。方法采用生长状态良好的hELF,经一定浓度的丝裂霉素C处理后,制备hELF饲养层,将ES细胞接种到该饲养层进行传代培养。观察ES细胞的形态学特征,测定ES细胞表面碱性磷酸酶（AKP）活性、干细胞标志物Oct-4的表达。结果hELF细胞经丝裂霉素C处理后不再增殖,保持较好的细胞功能和形态学特征。ES细胞克隆在饲养层呈现集落状隆起生长,边缘清楚,结构致密,与周围的饲养层细胞界限清楚。ES细胞仍然保持未分化状态,高度表达AKP及胚胎干细胞转录因子Oct-4。结论hELF作为饲养层可以较好的维持胚胎干细胞的生长及其未分化状态。hELF源自人工流产组织,取材来源较丰富,为hELF饲养层应用于人胚胎干细胞的培养奠定了基础。     

Insulin enhances the growth of cartilage in organ and tissue cultures of mouse neonatal mandibular condyle

Summary Condylar cartilages were cultured in the form of organ cultures on top of collagen sponges in medium containing 2% fetal calf serum and were treated with 3.5–350 nM insulin for 6 days. Doses of 175 nM of insulin caused a marked increase (+96%) in DNA synthesis and in proteoglycan production (+74%), features that manifested themselves structurally by a 60% increase in overall size of the cultured explants. Using a tissue culture system comprised of cartilage progenitor cells, insulin was found to enhance the differentiation of the progenitor cells so that by 6 days in culture and appreciable nodule of differentiated chondrocytes developed. The latter was surrounded by perichondrial cells whereas the extracellular matrix within the newly formed, insulin-induced, nodule reacted positively for cartilagespecific antigens (type II collagen and bone sialoprotein). It is suggested that insulin induces a direct stimulatory effect on progenitor cell proliferation, cartilage differentiation, and extracellular matrix deposition.     

Stereological study of the developing distal femoral growth plate

The distal femoral growth plate has a uniquely convoluted structure comprised of four mammillate processes. Factors contributing to the development of these processes and overall plate geometry were explored using three-dimensional image analysis of the canine distal femoral epiphysis. The growth plate at birth remains relatively flat until ossification of the epiphysis begins at 1 week of age. Epiphyseal ossification proceeds eccentrically, projecting in the medial-lateral and anterior-posterior directions. Growth plate activity indexed by [3H]thymidine labeling and plate thickness revealed regional differences in cell proliferation. This was measured as a decreased labeling index and thinning of the growth plate in areas capped by the ossifying epiphysis. The eccentric ossification pattern and associated variations in growth plate activity result in definition of an "intraphyseal" groove and medial-lateral oriented sulcus. The groove and sulcus bisect the plate into four quadrants, giving rise to a convoluted structure composed of four areas of plate elevations termed mammillary processes (MP). By 5 weeks, the pattern of ossification results in greater development of the MP in the anterior-medial quadrant and in decreasing order, in the posterior-medial, anterior, and posterior-lateral quadrants. By 10 weeks, a uniform rate of cell proliferation was observed coincident with completion of ossification of the epiphysis. The data suggest that localized variations in growth plate proliferation are associated with ossification of the epiphysis.(ABSTRACT TRUNCATED AT 250 WORDS)     

小鼠着床前胚胎miRNA表达的实验研究

目的研究微小RNA(miRNA)在小鼠着床前胚胎各发育阶段的表达谱,探讨miRNA在着床前胚胎发育中的作用和意义。方法建立小鼠超排卵、交配和胚胎收集系统,采用miRNA扩增、miRNA芯片和荧光实时定量逆转录聚合酶链反应(RT-PCR)的方法研究小鼠着床前胚胎miRNA表达。结果小鼠卵母细胞、2细胞胚胎、4~8细胞胚胎和囊胚分别表达55、53、62和72个miRNA;四个发育阶段共筛查到表达94个miRNA,32个在各发育阶段均表达,62个在不同发育阶段特异性表达。实时荧光定量PCR方法验证mmu-miR-721在小鼠着床前胚胎中表达。结论小鼠着床前胚胎表达大量的miRNA,其可能对胚胎发育和胚胎细胞的分化起重要调控作用。     

Electron microscopic analysis of mineral deposits in the calcifying epiphyseal growth plate

Summary Early mineral deposits within calcifying rat epiphyseal growth plates were studied by bright field and selected-area dark field electron microscopy, and X-ray microanalysis. These mineral deposits were preparedin situ by high-pressure freezing, freeze substitution, and low-temperature embedding, and were examined in unstained, stained, and ethyleneglycol tetraacetic acid (EGTA)-treated stained thin sections. On unstained sections mineral rods occur within an amorphous density of calcium and phosphorus (CaP). X-ray microanalysis of stained sections reveals that the location of electron-dense deposits does not always correspond to that of the CaP mineral deposits identified in electron microscopic images. Such an analysis showed a depletion of both Ca and P in stained sections at sites corresponding to high levels of these elements in unstained sections. Staining thus demineralizes early deposition sites of CaP; at the same time lead (Pb) and uranium (U) bind to the organic components of the extracellular matrix formerly associated with Ca and P. This substitution phenomenon alters the overall fine structure of mineral sites by depleting the amorphous density of Ca and P, and by creating isolated rodlike structures that have formerly been interpreted as representing hydroxyapatite (HAP) crystals. Selected-area dark field imaging shows nascent sites of HAP crystals to be associated with the limiting membrane of matrix vesicles, but such crystals were undetectable at these sites with conventional bright field images. Dark field imaging also showed that the typical 30–80 nm crystal rods found in calcified cartilage consist of aggregates of HAP crystals.     

Effects of transforming growth factor type β on expression of cytoskeletal proteins in endosteal mouse osteoblastic cells

Transforming growth factor β (TGFβ) has been shown to influence the growth and differentiation of many cell types in vitro. We have examined the effects of TGFβ on cell morphology and cytoskeletal organization in relation to parameters of cell proliferation and differentiation in endosteal osteoblastic cells isolated from mouse caudal vertebrae. Treatment of mouse osteoblastic cells cultured in serum free medium for 24 hours with TGFβ (1.5–30 ng/mL) slightly (− 23%) inhibited alkaline phosphatase activity. In parallel, TGFβ (0.5–30 ng/mL, 24 hours) greatly increased cell replication as evaluated by [³H]-thymidine incorporation into DNA (157% to 325% of controls). At a median dose (1.5 ng/mL) that affected both alkaline phosphatase and DNA synthesis (235% of controls) TGFβ induced rapid (six hours) cell respreading of quiescent mouse osteoblastic cells. This effect was associated with increased polymerization of actin, actinin, and tubulins, as evaluated by both biochemical and immunofluorescence methods. In addition, TGFβ (1.5 ng/mL) increased the de novo biosynthesis of actin, actinin, vimentin, and tubulins, as determined by [³⁵S] methionine labeling and fractionation of cytoskeletal proteins using two-dimensional gel electrophoresis. These effects were rapid and transient, as they occurred at six hours and were reversed after 24 hours of TGFβ exposure. The results indicate that the stimulatory effect of TGFβ on DNA synthesis in endosteal mouse osteoblastic cells is associated with a transient increase in cell spreading associated with enhanced polymerization and synthesis of cytoskeletal proteins.     

Vascular endothelial growth factor stimulates embryonic urinary bladder development in organ culture

OBJECTIVES: To determine whether vascular endothelial growth factor A (VEGF) and its receptors are expressed during bladder development in mice when capillaries are forming, and whether exogenous VEGF might enhance the growth of endothelia and other types of bladder cells, using an embryonic organ-culture model. MATERIALS AND METHODS: Whole bladders from wild-type mice, at embryonic day (E) 14, were grown in serum-free organ culture in an air/5% CO2 atmosphere; some cultures were supplemented with VEGF and/or with VEGF receptor 1/Fc chimera (VEGFR1/Fc), which blocks VEGF bioactivity. Organs were harvested after 6 days and the expression of VEGF and related molecules assessed using immunohistochemistry. RESULTS: VEGF, VEGFR1 and VEGFR2 positive cells were immunodetected in E14 and E18 bladders. Exogenous VEGF increased whole-organ growth, as assessed by explant areas, total cell numbers, DNA and protein content; proliferation was enhanced, and apoptosis decreased, in urothelium and surrounding tissues. VEGF also increased the proportions of cells expressing endothelial (CD31) and smooth muscle (alpha smooth muscle actin) markers. VEGFR1/Fc blocked the growth-enhancing effects of exogenous VEGF. CONCLUSIONS: In organ culture, exogenous VEGF not only stimulated embryonic bladder endothelial cells but also strikingly enhanced the growth of the whole organ. Whether the effects of VEGF on diverse bladder cell populations are direct or indirect requires further investigation. The finding that VEGF protein is present in embryonic bladders in vivo raises the possibility that it has similar actions during normal development. The results also illuminate the pathobiology of certain bladder diseases in which VEGF levels have been shown to be increased.     

Gene expression profiling of mouse growth plate cartilage by laser microdissection and microarray analysis

Longitudinal bone growth results from a complex sequence of events involving differentiation of resting chondroblasts into proliferative, pre-hypertrophic, and hypertrophic chondrocytes. The growth plate (epiphyseal plate), which is primarily responsible for longitudinal growth, can be divided into four distinct zones: the resting zone (RZ), proliferating zone (PZ), maturing zone (MZ), and hypertrophic zone (HZ), on the basis of the morphology of the developing chondroblasts and the structure of the cartilage matrix. In the past two decades substantial progress has been made in understanding the mechanisms underlying chondroblast differentiation and skeletal development [1–3]. However, comprehensive analysis of gene expression patterns in the growth plate has been technically challenging.     

白血病抑制因子在小鼠围着床期子宫内膜的表达

采用逆转录 -聚合酶链反应和免疫印迹法 ,研究了白血病抑制因子 (L IF)m RNA和蛋白在小鼠围着床期子宫内膜的表达规律。结果 :L IF m RNA在未孕期子宫内膜表达量极低 ,孕期升高 ,孕第四天达峰值 (P<0 .0 1 ) ,此后逐渐下降 ;LIF蛋白与 m RNA的表达规律一致 ,其水平在孕第四天达最高 ,显著高于未孕期 (P<0 .0 1 )。结果表明 L IFm RNA和蛋白孕早期子宫内膜的表达高峰与着床期一致 ,它可能参与了胚泡着床的启动     

组织型转谷氨酰胺酶在糖尿病大鼠肾组织中的表达及意义

目的 探讨组织型转谷氨酰胺酶(tTG)在糖尿病(DM)大鼠肾组织中的表达及其意义。 方法 链脲佐菌素(STZ)诱发大鼠制备DM模型，分别于第30、60、90和120天处死DM组大鼠6只、对照组(C组)3只。测定尿白蛋白量(AER)、肾重指数和血肌酐(Scr)。HE染色和PASM染色观察肾组织病理变化。免疫组织化学检测肾脏胶原Ⅳ(Col Ⅳ)和可溶性tTG表达。间接免疫荧光检测不溶性tTG分布。用RT-PCR检测总tTG mRNA表达。 结果 各个时间点DM组大鼠的AER、肾重指数和Scr均较C组明显升高(P < 0.05，P < 0.01)。DM组Col Ⅳ、可溶性tTG和不溶性tTG蛋白的表达均较C组明显增多(P < 0.05，P < 0.01)，且均随病程进展呈上升趋势。可溶性tTG和不溶性tTG蛋白水平都与AER呈正相关(r=0.937和0.809，P 均<0.01)。DM大鼠肾小球系膜区Col Ⅳ和不溶性tTG蛋白表达增加部位一致，且两者水平显著正相关(r=0.831，P < 0.05)。DM组总tTG mRNA的表达从第30天起开始上升、第90天达高峰，第120 天稍下降。 结论 tTG在DM大鼠肾组织的过度表达及不溶性tTG与Col Ⅳ表达的正相关，提示tTG可能参与了早期糖尿病肾病(DN)的发病过程。     

The effect of low sulfate concentrations on the glycosaminoglycan synthesis in anatomically intact articular cartilage of the mouse

We have studied the effect of environmental sulfate concentration on the glycosaminoglycan synthesis of anatomically intact patellar cartilage of the mouse in vitro. Incubation of mouse patellae in medium with sulfate concentrations below 0.5 mM resulted in a diminished incorporation of sulfate but in unaltered incorporation of glucosamine. This suggested the synthesis of undersulfated glycosaminoglycans under these conditions. We characterized glycosaminoglycans synthesized at three different sulfate concentrations: a sulfate concentration physiological for the mouse (1.0 mM), a sulfate concentration in the range where sulfate incorporation was strongly diminished (0.1 mM), and an extremely low sulfate concentration (10 nM). Analysis of glycosaminoglycan disaccharides and DEAE anion chromatography of the glycosaminoglycans could not confirm the synthesis of undersulfated glycosaminoglycans at 0.1 mM. The chromatogram of glycosaminoglycans synthesized in medium containing 10 nM showed the presence of a very low sulfated glycosaminoglycan pool not observed at higher medium sulfate concentrations. Intermediately sulfated glycosaminoglycans were also synthesized during incubation with 10 nM sulfate. So, our data indicate that only very low sulfate concentrations in the medium lead to the synthesis of undersulfated glycosaminoglycans and that the sulfation mechanism of murine patellar cartilage chondrocytes does not seem to fit completely in an "all-or-nothing" pattern.     

Epidermal growth factor in the mouse kidney: developmental changes and intranephron localizations

The developmental changes in epidermal growth factor (EGF) have been studied in tissue homogenates, kidney slices, and microdissected nephron segments of the mouse. Immunoreactive EGF concentration per milligram of protein increased in the kidney by about 20-fold from 1 week to 3 weeks of life, reaching the highest levels between 5 and 7 weeks, and decreasing by 10 weeks of life. The time course of the changes was different from those of submaxillary and urinary EGF. Above 7 weeks of age, kidney EGF was higher in female than in male mice. Among various zones of the kidney (outer cortex, inner cortex, outer medulla I, II and papilla), the outer medulla I and II contained the highest quantities of EGF per gram of wet tissue. The highest EGF content per millimeter length was observed in the medullary and cortical thick ascending limbs of Henle's loop. The amounts exceeded by about 4.5-fold those found in glomeruli and in proximal convoluted and proximal straight tubules, and by about 3-fold those present in distal and collecting tubules. Unilateral nephrectomy resulted in no significant changes in EGF levels in the contralateral kidney. The results suggest that the ontogeny of kidney EGF is different from that of the EGF found in the submaxillary gland, and that there is nephron heterogeneity in EGF content.     

Distribution of acidic glycosaminoglycans in rabbit growth plate cartilage

Chondroitin-4-sulfate (C-4-S), chondroitin-6-sulfate (C-6-S) and keratan sulfate (KS) concentrations were measured in growth plate cartilage derived from rabbits of two different ages, and from three growth plate zones from rabbits of the same age. With increasing age, the concentration of C-4-S increased, C-6-S decreased and KS remained constant. There was no variation when three different growth plate zones were sampled. Radiosulfate uptake into chondroitan sulfate was also measured, and this showed an inverse relationship to concentration with increasing age.Research supported in part by a grant from the Western Chapter (Pennsylvania) Arthritis Foundation; Research Grant AMI 1382-04 from the National Institute of Arthritis and Metabolic Diseases; and the Orthopaedic Research Fund, The Hospital for Joint Diseases.     

软骨生长因子的提取、纯化及生物活性测定

目的：通过从鸡软骨中提取具有生物活性的软骨生长因子（CDGF）,为进一步进行体内研究成罗效应及临床应用打下基础,方法：采用氯化钠抽提法分离,制备软骨粗提取物;用肝素－琼脂糖亲合色谱反复层析提纯软骨生长因子;以聚丙烯酰胺凝胶电泳和银染色分析软骨生长因子;采用MTT法对CDGF在培养的软骨细胞上进行活性测定。结果：软骨生长因子能与肝素－琼脂糖紧密结合,亲合层析中,在1．4－1．8mol/LNaCl缓冲液中洗脱出。通过SDS－PAGE凝胶电泳和银染色检测,得到分子量为18500的单一条带,高度纯化的CDGF,其生物活性约1－2ng/ml。结论：肝素－琼脂糖亲合色谱复层析,可以从鸡软骨中得到活性较高,电泳显示单一条带的CDGF。     

新建辅助生殖实验室的鼠胚培养质控及鼠卵显微注射分析

目的利用小鼠体外受精法和体内受精法胚胎培养检测新建辅助生殖实验室的质控情况,分析比较常规人卵显微注射模式与鼠断尾精子显微注射模式的结局。方法利用昆明小鼠进行胚胎培养质控分析,按照受精方式不同分为体内受精组和体外受精组;又根据显微注射方式的不同,分为常规人卵显微注射模式(C-ICSI组)和鼠断尾精子显微注射模式(D-ICSI组),分析比较不同方式的鼠卵ICSI结局。结果体内受精组的受精率显著高于体外受精组(91.90%vs. 81.59%,P<0.05),两组的卵裂率(94.24%vs. 93.39%)、囊胚形成率(85.97%vs. 81.67%)比较无显著性差异(P>0.05)。人卵显微注射系统应用于鼠ICSI时卵子存活率有降低的趋势,但C-ICSI组与D-ICSI组的卵子存活率比较无显著性差异(29.49%vs. 30.52%)(P>0.05);D-ICSI组的受精率(56.72%vs. 42.53%)、卵裂率(71.05%vs. 43.24%)及囊胚形成率(61.11%vs. 31.25%)显著高于C-ICSI组(P<0.05)。结论昆明小鼠配子体外受精法...     

Hepatocyte growth factor in human osteoarthritic cartilage

OBJECTIVE: Hepatocyte growth factor/scatter factor is a potent mitogen, morphogen and motogen for a variety of mainly epithelial cells. Hepatocyte growth factor is synthesized by mesenchymal cells and can be found in various tissues. The objective of this study was to investigate the expression and distribution patterns of this pleiotropic growth factor and its receptor, the product of the proto-oncogene c-met in normal and osteoarthritic human knee cartilage. METHODS: Five normal and 14 osteoarthritic human cartilage samples graded histomorphologically by Mankin Score, were studied by radioactive in-situ hybridization and immunohistochemistry for the expression of Hepatocyte growth factor and the c-met receptor. RESULTS: Hepatocyte growth factor could be found by immunohistochemistry in the territorial matrix surrounding the chondrocytes of calcified cartilage and within the deep zone of normal cartilage. Chondrocytes of these cartilage zones showed also positive c-met receptor-staining. Moreover, a small number of chondrocytes in the superficial and intermediate zone showed c-met staining. In accordance with the increased hepatocyte growth factor staining of osteoarthritic cartilage, an enhanced expression of hepatocyte growth factor-RNA by chondrocytes of the deep zone as well as the deeper mid zone was observed. Contrary to normal cartilage, c-met was identified immunohistochemically in osteoarthritic chondrocytes of all cartilage zones. CONCLUSION: These results indicate that hepatocyte growth factor seems to be acting in an autocrine/paracrine manner in normal and osteoarthritic cartilage. The ubiquitous presence of the HGF/HGF-receptor complex in osteoarthritic chondrocytes suggests that hepatocyte growth factor may contribute to the altered metabolism in osteoarthritic cartilage.     

Protein-polysaccharide synthesis at three levels of the normal growth plate

A method is presented for separating the proliferative, maturing and hypertrophic cell zones of the epiphyseal growth plate of the weanling rabbit, in such a manner that protein-polysaccharide metabolism could be studiedin vitro on a per-cell basis. Using the timed incorporation of³⁵SO₄ as an index of protein-polysaccharide synthesis, and hexosamine concentration as an index of protein-polysaccharide content per zone, it was found that sulfate uptake varied inversely with matrix protein-polysaccharide content; being highest in the hypertrophic cell layer where matrix content was least. The possible significance of this relationship is discussed.

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Zusammenfassung Es wird eine Methode zur Trennung der proliferativen, reifenden und hypertrophen Zellzonen der Epiphysenwachstumsplatte beim entwöhnten Kaninchen besprochen, die es ermöglicht, den Protein-Polysaccharid-Metabolismusin vitro für jeden Zelltyp gesondert zu untersuchen. Als Index der Protein-Polysaccharid-Synthese wurde die zeitbedingte Aufnahme von³⁵SO₄-Ionen verfolgt, während als Index des Protein-Polysaccharidgehaltes der Zonen die Hexosaminkonzentration gemessen wurde. Bei diesem Vorgehen wurde gefunden, daß die Sulfataufnahme entgegengesetzt zum Protein-Polysaccharidgehalt der Matrix variiert, indem sie die höchsten Werte in der hypertrophen Zellschicht auftweis, wo der Matrixgehalt am kleinsten ist. Die Bedeutung dieses Verhältnisses wird besprochen.

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Résumé Une méthode de séparation des zones cellulaires de prolifération, de maturation et d'hypertrophie de la métaphyse épiphysaire du jeune lapin est mise au point, de façon à pouvoir étudier le métabolisme protéino-polysaccharidiquein vitro sur une base cellulaire. En utilisant l'incorporation de³⁵SO₄ comme index de la synthèse protéino-polysaccharidique et la concentration en hexosamine comme index du contenu en protéine-polysaccharide par zone, il apparait que la concentration en sulfate varie inversement avec le contenu en matrice protéino-polysaccharidique: elle est la plus élevée dans la couche des cellules hypertrophiques où le contenu en matrice est le plus bas. La signification possible de ce rapport est envisagée.