Effect of encephalectomy on corticosterone content in the fetal rat adrenals

The functional state of the pituitary-adrenal system was studied after removal of the hypothalamus from rat fetuses (encephalectomy in utero). Hormonal activity of the adrenal glands was estimated by fluorometric determination of their corticosterone content. Removal of the hypothalamus in fetuses aged 18.5–19.5 days lowered the adrenal corticosterone level. Injection of a homogenate of the hypothalamus into the fetuses immediately after encephalectomy prevented this decrease. The results confirm the presence of a functional link between the hypothalamus and the pituitary-adrenal system in rat fetuses.Laboratory of Hormonal Regulation, Institute of Developmental Biology, Academy of Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Kraevskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 5, pp. 597–598, May, 1976.     

Selective inhibition by chloramphenicol of ACTH-induced reorganization of inner mitochondrial membranes in fetal adrenal cortical cells in tissue cultures

Tissue cultures of fetal rat adrenals were used to study effects of chloramphenicol on the ACTH-induced synthesis of mitochondrial inner membranes in the cortical cells. Chloramphenicol alone added to the culture medium in concentrations of 0.003, 0.03, 0.3, and 0.6 μ mole/ml/6 days induced no changes in the ultrastructure of cortical cells. Chloramphenicol in concentrations of 0.3 and 0.6 μ mole/ml/6 days given together with 100 mu/ml/6 days of ACTH inhibited completely the ACTH induced changes of mitochondrial inner membranes (formation of 600 Å vesicles). Chloramphenicol in concentrations of 0.003 μ mole/ml/6 days caused no inhibition of the ACTH effects. In concentration of 0.03 μ mole/ml/6 days chloramphenicol resulted in incomplete inhibition of ACTH-induced formation of mitochondrial vesicular cristae. None of these doses of chloramphenicol affected other ACTH-induced changes in the fine structure of the cells such as increase of smooth surfaced endoplasmic reticulum, hypertrophy of Golgi apparatus, and development of microvillous processes of plasma membranes. Chloramphenicol also caused no inhibition of the ACTH-induced accumulation of lipid in the cytoplasm. In cultivated cortical cells of Charles River strain albino rats small groups of annulated lamellae are commonly observed. The present observations suggest that: (1) the development of mitochondrial inner membranes is dependent, at least in part, on mitochondrial protein synthesis; (2) ACTH stimulation of mitochondrial protein synthesis in cortical cells is independent of ACTH-induced stimulation of nuclear-DNA-dependent protein synthesis; (3) doses of chloramphenicol which inhibit specialization of mitochondrial inner membranes of fetal adrenal cortical cells are comparable to those which inhibit protein synthesis in bacteria.     

Inhibition of IgE binding to tissue culture cells and leucocytes by pentapeptide.

The specific binding of radiolabelled IgE to a tissue culture lymphoblastoid cell line (Wil-2WT) was confirmed. The binding of IgE and Hamburger's IgE-derived pentapeptide Asp-Ser-Asp-Pro-Arg (HEPP) to Wil-2WT cells and to human leucocytes was compared. HEPP inhibition of IgE binding to leucocytes averaged 24% but with Wil-2WT cells only 12% inhibition was observed with double the amount of HEPP. Using myeloma IgE to inhibit the binding of tritiated HEPP to leucocytes and Wil-2WT cells confirmed the specificity of the peptide binding as well as the greater affinity of HEPP for leucocytes (basophils) compared to Wil-2WT lymphoblastoid cells. Based upon the extent of binding and the maximum inhibition attainable with HEPP it is suggested that the receptors for IgE on Wil-2WT cells, basophilic leucocytes and mast cells are not identical but that they share specificities in common. A new hypothesis for the mechanism of action of HEPP is proposed.     

Isolation and primary culture of rat renal cortical epithelial cells

Summary Methods are described for the isolation of rat renal cortical epithelial cells by a collagenase and hyaluronidase perfusion, followed by pressing fragments of renal cortex through an 80-mesh screen and further enzymatic dissociation in vitro. Primary monolayer cultures are derived from the resulting suspension of tubular fragments and cells. Fibroblast and endothelial cell overgrowth is suppressed by the use of medium lacking arginine and containingd-valine in place ofl-valine. Further separation of fibroblasts from epithelial cells is achieved by a technique that takes advantage of the differential rate of attachment of the two cell types. The presence of glomerular cells in the cultures is diminished by a complete medium change 48 h after plating the cells.     

Dexamethasone induces proliferation and terminal differentiation of osteogenic cells in tissue culture

Dexamethasone is an important regulator of cellular proliferation and differentiation, but paradoxical effects have been noted in a variety of culture systems. The purpose of this study was to determine whether dexamethasone induces proliferation and differentiation of osteogenic precursor cells. Periosteal explants from embryonic chicks were grown in culture for 3 or 4 days, treated continuously with dexamethasone or ethanol vehicle, and then either pulse-labeled with 3H-thymidine at 3 days or labeled for 24 hr between day 3 and day 4. Histochemical and autoradiographic procedures were used to assess the proliferation and differentiation of osteogenic cells. At 3 days, the area of bone, the percentage of alkaline phosphatase-positive cells, the percentage of 3H-thymidine-labeled cells, and the percentage of cells labeled with both markers were significantly higher in dexamethasone-treated cultures. Between day 3 and day 4 no significant changes in these parameters were observed in the dexamethasone-treated cultures. In comparison, control cultures exhibited significant increases in the percentage of 3H-thymidine-labeled cells after 24 hr of continuous labeling. The data show that dexamethasone induces a burst of proliferation in a cohort of cells that undergo differentiation. Once these cells have divided, further proliferation within the culture is limited. Finally, it is apparent that the timing of experiments may be critical in determining whether dexamethasone will inhibit or stimulate proliferation.     

Proliferation and differentiation of cells from explants of fetal rat stomach

The current understanding of the mechanisms controlling the proliferation and differentiation of the stem cells of the gastric oxyntic glands is limited. The aim of the present study was to develop a method for investigating proliferation and differentiation of undifferentiated cells from fetal rat stomach. Outgrowth of cells was initiated from explants of 16-day-old fetal rat stomachs. At this stage of the fetal development the gastric epithelial cells are undifferentiated. The explants were cultured in DMEM/F-12 medium supplemented with fetal calf serum only, or fetal calf serum combined with either hydrocortisone or pentagastrin. Morphological characterization by means of light microscopy, dye staining and immunostaining was used to identify the growing cells. Both hydrocortisone and pentagastrin accelerated the differentiation towards H,K-ATPase-positive cells, mucus-producing cells and other epithelial cells. H,K-ATPase-positive cells, which were identified by immunostaining with a monoclonal antibody reacting with the α-subunit of the H,K-ATPase, grew on top of the confluent layer of epithelioid and fibroblastoid cells. With this method in vitro investigations of the mechanisms of proliferation and differentiation of gastric mucosal cells are possible. Although by different mechanisms, both hydrocortisone and pentagastrin appear to play a regulatory role in these processes.     

脑源性神经营养因子基因修饰的胚胎大鼠皮质神经干细胞及其在体外的分化

目的 探讨脑源性神经营养因子（BDNF）基因修饰大鼠脑皮质神经干细胞（NSCs）后BDNF的表达,并观察其对NSCs体外诱导分化的影响。 方法 体外分离、培养大鼠胚胎脑皮质神经干细胞并鉴定;构建BDNF基因重组质粒,非脂质体法转染NSCs,实验分为pcDNA3-1- BDNF组、pcDNA3-1组和未转染NSCs组。免疫细胞化学技术和RT-PCR检测转染后BDNF蛋白和mRNA的表达;在含5％胎牛血清的分化培养基中诱导分化,βIII微管蛋白、神经胶质纤维酸性蛋白（GFAP） 和突触素( SYP)免疫细胞化学染色对分化细胞进行鉴定,并观察pcDNA3-1-BDNF转染NSCs分化过程中SYP的表达变化。 结果 体外培养获得巢蛋白（nestin）阳性的NSCs。成功构建BDNF基因重组质粒,免疫细胞化学和RT-PCR检测均显示,与pcDNA3-1组和NSCs组比较,pcDNA3-1-BDNF组NSCs的BDNF表达明显增强（P<0.05）。pcDNA3-1组和NSCs组比较,无显著性差异（P＞0.05）。分化后第4天,各组细胞均可分化为Βiii-微管蛋白阳性和GFAP阳性细胞,pcDNA3-1-BDNF组可见少量SYP阳性表达细胞。分化后第7天,与pcDNA3-1组和NSCs组比较,pcDNA3-1-BDNF组NSCs分化为βIII微管蛋白阳性神经元的比例明显增高,有显著性差异（P<0.05）,SYP阳性细胞数增多,表达增强。 结论 BDNF转染NSCs具有体外分泌BDNF的能力,能够促进NSCs定向分化为神经元,SYP表达增强,可能在促进神经元之间的突触发生中发挥作用。     

Cell differentiation in the terminal tubule of fetal rat submandibular gland in organ culture

Submandibular glands from 17-day-old rat fetuses were maintained in organ culture for five days in a medium consisting of Eagle's MEM (87%), horse serum (10%), and chick embryo extract (3%). Each day of the culture period explants were incubated for the demonstration of peroxidase activity and processed for light and electron microscopic observations. In some experiments cultures were exposed to ³H-thymidine one hour prior to fixation and incubation for the demonstration of peroxidase activity. Labelling index was determined using radioautographs of 1 μ Epon-embedded sections. At the time of explantation the submandibular gland rudiment consisted of undifferentiated epithelial cells arranged in cords. On day 3 of culture two additional cell types could be distinguished: terminal tubule cells and proacinar cells. The proacinar cells were characterized by peroxidase activity in their granules and cytoplasm. By day 4 acinar cells begin to appear. On the fifth day of culture the four cell types of the terminal tubule were present in the following proportions: undifferentiated cells, 44%; terminal tubule cells, 19%; proacinar cells, 31%; acinar cells, 6%. These results indicate that the cytodifferentiation of the secretory unit of rat submandibular gland in vitro is comparable to the differentiation in vivo.     

共培养环境中大鼠胚胎中脑细胞诱导人脐带间充质干细胞分化

目的:检测人脐带间充质干细胞(human umbilical cord mesenchymal stem cells,hUCMSCs)在与大鼠胚胎中脑细胞共培养环境中酪氨酸羟化酶(tyrosine hydroxylase,TH)和多巴胺转运蛋白(dopamine transporter,DAT)表达的变化。方法:(1)植块法分离培养hUCMSCs,以细胞免疫化学法鉴定其表面特异性标记物的表达;(2)无菌条件下分离E15大鼠胚胎中脑组织,制成单细胞悬液及中脑组织提取液;(3)用大鼠胚胎中脑组织提取液做培养液,将5-溴脱氧尿嘧啶核苷(bromodeoxyuridine,BrdU)标记的hUCMSCs与大鼠胚胎中脑细胞共培养14 d,细胞免疫化学法检测hUCMSCs中TH和DAT的表达。结果:HUCMSCs高表达CD29、CD44、CD73、CD90和CD105,极低表达CD31和CD45。在与大鼠胚胎中脑细胞共培养14 d后,hUCMSCs中TH阳性表达率为(18.06±2.29)%,DAT阳性表达率为(11.14±2.10)%。结论:用植块法可成功分离并体外培养hUCMSCs,其免疫表型符合间充质干细胞(mesenchymal stem cells,MSCs)的特征。在以大鼠胚胎中脑组织提取液作为培养液,并与大鼠胚胎中脑细胞共培养的诱导条件下,hUCMSCs可部分向多巴胺能神经元分化。     

Cell differentiation in the terminal tubule of fetal rat submandibular gland in organ culture.

Submandibular glands from 17-day-old rat fetuses were maintained in organ culture for five days in a medium consisting of Eagle's MEM (87%), horse serum (10%), and chick embryo extract (3%). Each day of the culture period explants were incubated for the demonstration of peroxidase activity and processed for light and electron microscopic observations. In some experiments cultures were exposed to 3H-thymidine one hour prior to fixation and incubation for the demonstration of peroxidase activity. Labelling index was determined using radioautographs of 1 mu Epon-embedded sections. At the time of explantation the submandibular gland rudiment consisted of undifferentiated epithelial cells arranged in cords. On day 3 of culture two additional cell types could be distinguished: terminal tubule cells and proacinar cells. The proacinar cells were characterized by peroxidase activity in their granules and cytoplasm. By day 4 acinar cells begin to appear. On the fifth day of culture the four cell types of the terminal tubule were present in the following proportions: undifferentiated cells, 44%; terminal tubule cells, 19%; proacinar cells, 31%; acinar cells, 6%. These results indicate that the cytodifferentiation of the secretory unit of rat submandibular gland in vitro is comparable to the differentiation in vivo.     

Autophagic degradation of mitochondria in white adipose tissue differentiation

Recent work has revealed that autophagy plays a significant role in the process of white adipocyte differentiation. In both in vitro and in vivo model systems, autophagy inactivation by targeted deletion of essential autophagy genes results in alterations in white adipocyte structure. In both models, postdifferentiation cells exhibit atypical morphology, with many small lipid droplets and large numbers of mitochondria, rather than the single large lipid droplet and relatively few mitochondria observed in normal white adipocytes. The role of autophagy as the primary means of the degradation of mitochondria has long been studied, and it is likely that a deficiency in the degradation of mitochondria contributes to the unusual phenotypes observed in mice with autophagy-deficient adipose tissue, including reduced adiposity, resistance to diet-induced obesity, and increased insulin sensitivity. What is not yet known is whether the process of mitochondria-specific autophagy, often referred to as "mitophagy," is specifically induced during adipogenesis or if a general increase in the nonspecific autophagic degradation of mitochondria plays a role in normal adipose differentiation. Despite remaining questions, these findings not only establish the critical role of autophagy in white adipose tissue development, but also suggest that the manipulation of autophagy in adipose tissue may provide novel therapeutic opportunities for metabolic diseases.     

Inhibition of ascorbate autoxidation by a rat brain cortical factor

The soluble fraction of rat brain cortex yielded an antioxidant factor that inhibits the autoxidation of ascorbic acid at physiological pH. The measurements were based on spectrophotometric detection of ascorbic acid at 265 nm in a physiological salt solution of the Krebs-Ringer type, pH 7.4, or in sodium phosphate buffer, pH 7.4. In these systems the autoxidation of ascorbate was linear with respect to time for at least 60 min. The potency of the antioxidant factor is indicated by the fact that half maximal inhibitory activity was obtained with an extract representing approximately 10,000-fold dilution of cell components. The inhibitory activity of the cortical tissue was solubilized during heat treatment. A considerable portion of the activity was released by brain slices into the medium during incubation in normal Krebs-Ringer phosphate medium.     

Differentiation of alpha cells in the fetal rat pancreas grown in organ culture

Alpha cells can be demonstrated in embryonic rat pancreas by a modification of the Grimelius silver nitrate technique. At the start of culture at 18 days of gestation, alpha cells are closely associated with exocrine tubules and beta cells. After ten days of culture they are arranged peripherally around a mass of beta cells, in islets that are characteristic of adult rat pancreas.     

Lung fibroblasts improve differentiation of rat type II cells in primary culture

Epithelial-mesenchymal interactions mediate prenatal lung morphogenesis and differentiation, yet little is known about their effects in the adult. In this study we have examined the influence of cocultured lung fibroblasts on rat alveolar type II cell differentiation in primary culture. Type II cells that were co-cultured with lung fibroblasts showed significant increases in messenger RNA (mRNA) levels of surfactant protein (SP)-A, SP-B, SP-C, and SP-D. Metabolic labeling and immunohistochemistry demonstrated that these mRNAs were translated and processed. Addition of 10(-7) M dexamethasone (DEX) to cocultures antagonized the effects of the fibroblasts on SP-A and SP-C, but significantly augmented the effects on SP-B; expression of SP-D was unaffected. Coculture of type II cells with lung fibroblasts also increased acetate incorporation into phospholipids 10-fold, which was antagonized by DEX. Keratinocyte growth factor (KGF) mimicked the effects of lung fibroblasts on SP gene expression, but KGF neutralizing antibodies only partially reduced the effects of lung fibroblasts. KGF increased acetate incorporation into surfactant phospholipids, and the addition of DEX augmented this response. Together, our observations suggest that epithelial--mesenchymal interactions affect type II cell differentiation in the adult lung, and that these effects are partially mediated by KGF.     

Trophic effects of insulin-like growth factor-I on fetal rat hypothalamic cells in culture

The hypothesis that insulin-like growth factor-I is a trophic factor for primary fetal rat hypothalamic cells was tested, since we previously reported a potent mitogenic effect of this peptide on virally-transformed hypothalamic cells. It was found that insulin-like growth factor-I produced significant and dose-dependent increases in the survival of fetal hypothalamic neurons in primary mixed glial/neuronal cultures. By 48 h in vitro, cultures treated with insulin-like growth factor-I (6 nM) had twice as many neurite-bearing cells as controls, while by day 15 a five-fold difference was present. The peptide was similarly active in promoting neuronal survival in neuron-enriched (98% neurons) hypothalamic cultures. Mixed hypothalamic cultures had specific binding sites for insulin-like growth factor-I. In addition, the neurons grown in the presence of insulin-like growth factor-I had a more differentiated morphology and had significantly higher levels of protein kinase C, an enzyme that increases during neurite formation and synaptogenesis. Finally, glial-enriched cultures (greater than 99% glial cells) obtained from the fetal hypothalamus showed increased [3H]thymidine incorporation in response to insulin-like growth factor-I. These results further support the contention that insulin-like growth factor-I is a neurotrophic factor and suggest that it may participate in the normal development of the hypothalamus by increasing neuronal survival/differentiation and stimulating glial growth.     

Inhibition of bone resorption in tissue culture by H1-receptor antagonists

Mouse bone culture studies show that several representative H1-receptor antagonists, promethazine hydrochloride, pyrilamine maleate, tripelennamine hydrochloride, and diphenhydramine hydrochloride, inhibit parathyroid extract-stimulated bone resorption. The H2-receptor antagonists, metiamide and cimetidine, are ineffective. In view of the finding that histamine and histamine agonists did not stimulate bone resorption, it is unlikely that histamine receptors are involved in mediating parathyroid extract-stimulated bone resorption. Because H1-receptor antagonists bind to phospholipids and have been shown to influence membrane structure and function, it is suggested that they inhibit bone resorption by a mechanism that depends on their membrane-stabilizing effect.     

结缔组织对人胎骨髓间充质干细胞向上皮分化的诱导作用

目的 探讨结缔组织诱导人胎儿骨髓间充质干细胞（BMSCs)分化为上皮细胞的机制。 方法 取20例孕16～20周因故引产胎儿,10例选择性剖宫产妇羊膜,酶联免疫吸附测定（ELISA）法检测去上皮羊膜和胎儿肠壁结缔组织中表皮生长因子(EGF)的含量;分离、培养、扩增胎儿BMSCs;将4,6-二脒基-2-苯基吲哚（DAPI）标记的第3代BMSCs（P3-BMSCs）种植于羊膜上,分别加入肠壁结缔组织上清液、羊膜上清液（均含EGF 30μg/L）、外源性EGF 30ug/L、30ng/L、完全培养基（1～5组）中。培养7d后,免疫组织化学和激光扫描共焦显微镜检测BMSCs表达的细胞角蛋白(CK)及CK20。 结果 每100mg肠壁结缔组织及羊膜中EGF含量分别为（320.22±0.257）pg、（299.20±0.994）pg。羊膜与肠壁结缔组织上清液或羊膜上清液联合诱导BMSCs后,其CK和 CK20阳性细胞率均明显强于羊膜与外源性EGF诱导组以及单纯羊膜诱导组,P＜0.01。羊膜与肠壁结缔组织上清液诱导后BMSCs表达CK20高于羊膜与羊膜上清液组,P＜0.05。羊膜诱导组与外源性EGF联合诱导组间的差异无统计学意义。 结论 直接接触可能是羊膜结缔组织诱导BMSCs向上皮细胞分化的机制之一。肠壁结缔组织上清液和羊膜上清液均能联合羊膜诱导BMSCs向上皮细胞及具有肠上皮细胞表型的细胞分化。