The authors studied Witschi's theory of "corticomedullary inductors" with the; heterosexual grafts of the embryonal gonads of the rats in very close proximity or in remote distance each other for the effect of the inductor substance and the possibility of the substance acting as blood-borne agent when multiple embryonal testes and one or two ovaries were separately grafted in distant sites in the mammalian level. The heterosexual grafts of the embryonal gonads aging 16 days old were performed as the methods Macintyre (1956) used. Additionally the author grafted one or two embryonal ovaries of the same age in the subcapsular site and multiple embryonal testes of the same age in the similar site of the opposite kidney of the same host and allowed to develop at the sites for 3 weeks. The explants removed from the host, were fixed in Bouin's fluid, embedded in paraffin, sectioned serially at 6mu, and stained with hematoxylin and eosin. The embryonal transplanted ovary with testis in close contact, was inhibited and depressed to the one side probably due to the more rapid growth and differentiation of the testis as compared with the ovary and contained a tubular structure (seminiferous-like tubule) in which the degenerating oocytes were found. The author presumed the testicular effect upon the mutual ovary as the activity of the diffused inductor substance derived from the testis. In the group, which more than 15 embryonal testes (maximally 25 testes were grafted) were transplanted in the subcapsular site and one or two ovaries in the opposite site of the kidney of the same host, the ovarian grafts, which were at a distant site from the multiple testicular grafts, showed inhibited growth and differentiation by the similar appearance of the transplanted embryonal ovary with testis in mutual contact. By this observation the author considered the inhibited growth and differentiation of the effect of blood-borne inductor substance derived from the multiple testicular grafts of the opposite site of the host kidney.
Animals ; Castration ; Female ; Male ; Ovary/*embryology/*transplantation ; Rats ; Testis/*embryology/*transplantation

OBJECTIVEMany studies have shown that tissue development is closely correlated with fluid transport. Aquaporins (AQPs) are a group of cell membrane proteins that actively and selectively transport water. This study aimed to investigate the changes of AQPs expression during lung development in rats in order to elucidate the role of AQPs in the rat lung development.

METHODSAQP1, AQP3, AQP4 and AQP5 proteins and mRNA in the lung cell membrane were measured by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) respectively in the 20-day-old embryo (E20), 7-day-old newborn rat, and one-month-old young and adult rats. The correlation between AQPs expression and lung development was studied.

RESULTSWith increasing age, the lung development showed a dynamic and successive course, with the most rapid from the fetus to the newborn rat, and then a slowed down afterwards. AQPs mRNA was weakly expressed in the lung of the E20 group. Lung AQPs mRNA and protein increased rapidly after birth until adulthood. The AQPs distribution patterns in the lung were unique with no duplication. There was a positive correlation between AQPs expression and lung development (P<0.05).

CONCLUSIONSIn addition to being involved in the transepithelial transport of water in the lung, AQPs is also related to its development.

Animals ; Aquaporins ; analysis ; genetics ; physiology ; Immunohistochemistry ; Lung ; embryology ; metabolism ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar

In order to investigate the expression patterns of the transforming growth factor (TGF)beta isoforms in the internal ear, an immunohistochemical study of rat embryos was performed. Rat embryos were taken on the 13th, 15th, 17th, and 19th day after conception and their internal ears were immunohistochemically stained against TGF beta1, beta2, and beta3. As a result, the 13-day-old embryo showed a very weak positivity to TGF beta1. After the 15th day of pregnancy, no reactivity to TGF beta1 was defected. Immunoreactivity to TGF beta2 was observed from the 15th day of pregnancy throughout the rest of the period. The ampulla of the semicircular canal and the cochlear duct showed a notably strong immunohistochemical reaction. A strong reaction to TGF beta3 was observed on the 15th day of pregnancy. However, no positive reactions were observed thereafter. A strong immunoreactivity was observed especially on the apical cytoplasms, the surfaces of the epithelial cells, and basement membranes of the cochlear duct, as well as the semicircular canals of the developing internal ear of rat embryo.
Animals ; Ear, Inner/embryology/*metabolism ; Embryo/embryology/*metabolism ; Female ; Immunohistochemistry ; Male ; Rats ; Rats, Sprague-Dawley ; Time Factors ; Transforming Growth Factor beta/*biosynthesis

OBJECTIVETo study the effect of maternal vitamin D deficiency on lung morphogenesis and platelet-derived growth factor-A (PDGF-A) expression in rat offspring.

METHODSSprague-Dawley (SD) female rats were randomly divided into two groups: normal control and vitamin D deficiency, with 6 rats in each group. The vitamin D deficiecy group was kept away from light and fed with the forage without vitamin D. After 2 weeks, the rats were mated with normal SD male rats. The morphological changes of fetal rat lungs on day 20 of gestation and 1-day-old neonatal rat lungs were observed by light microscope and electronic microscope. The levels of PDGF-A mRNA and protein in fetal and neonatal rat lungs were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) technique and Western blot method respectively.

RESULTSUnder the light microscope, smaller alveolar space, smaller diameter of the respiratory membrane and thicker alveolus mesenchyma were observed in lungs of fetal and neonatal rats from the vitamin D deficiency group compared with the controls (P<0.05). Under the electronic microscope, fewer lamellar bodies but more glycogen deposition in intracytoplasm were observed in the lungs of fetal rats from the vitamin D deficiency group compared with the controls. There was an increased number of empty lamellar bodies in neonatal rats from the vitamin D deficiency group. The levels of PDGF-A mRNA and protein in lungs of fetal and neonatal rats from the vitamin D deficiency group were significantly lower than the controls (P<0.05).

CONCLUSIONSMaternal vitamin D deficiency during pregnancy may inhibit the development of lung morphogenesis and PDGF-A expression in late fetal and neonatal rats. The low expression of PDGF-A may be involved in the inhibitory effect of vitamin D deficiency on the lung development.

Animals ; Calcifediol ; blood ; Female ; Lung ; embryology ; pathology ; ultrastructure ; Platelet-Derived Growth Factor ; analysis ; genetics ; metabolism ; Pregnancy ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Vitamin D Deficiency ; embryology ; metabolism

OBJECTIVETo investigate whether the suppression of Wnt10b by siRNA could prevent the development of hair follicle in the cultured rat embryonic skin.

METHODSsiRNA-Wnt10b was synthesized by chemosynthesis method. The dorsal skin of SD rat at embryos were cultured in DMEM in the presence of different percentage of interfering RNA targeting Wnt10b. Wnt10b/beta-catenin expression was analyzed by real-time PCR everyday and by Western blot on the third day. The cultured embryonic skin underwent paraffin embedding, section, HE staining on the third day,in which the number of de novo hair follicle was calculated and statistically analyzed.

RESULTSWnt10b gene in the cultured embryonic skin could be knocked down with the siRNA-based method. Beta-catenin mRNA was not greatly influenced by the downregulation of Wnt10b mRNA. The number of de novo hair follicle placode in cultured embryonic skin decreased, along with the downregulation of Wnt10b and beta-catenin proteins expression.

CONCLUSIONSThe downregulation of Wnt10b mRNA and protein by siRNA reduces the number of de novo hair follicle placode in the cultured rat embryonic skin. Wnt10b may control cytoplasm beta-catenin concentration at the protein level.

Animals ; Hair Follicle ; embryology ; metabolism ; RNA, Messenger ; genetics ; RNA, Small Interfering ; genetics ; Rats ; Skin ; embryology ; metabolism ; Tissue Culture Techniques ; Wnt Proteins ; genetics ; metabolism ; beta Catenin ; metabolism

OBJECTIVEThe aim of this study was to investigate the ability of Pref-1+ adipocyte progenitor cells to mobilize into mesenteric lymph nodes (MLNs) and the dynamic expression of related chemokines during the development of rat MLNs.

METHODSImmunohistochemical analyses were used to detect the expression of Pref-1 and related chemokines. Transmission electron microscopy (TEM) was used to observe the changes in ultrastructure of MLNs.

RESULTSCells containing lipid droplets were found in all rat MLNs at embryonic day (E) 18.5, 2 and 6 weeks (w) after birth, and they were similar to fibroblastic reticular cells (FRCs) or follicular dendritic cells (FDCs) under TEM. Pref-1+ adipocyte progenitor cells were found in all MLNs. The expression level of Pref-1 was significantly increased at 2 w after birth and decreased at 6 w after birth. The tendency of Cxcl12 expression was consistent with that of Pref-1 and was positively correlated with the expression of Pref-1 (P < 0.01; r = 0.897). At E18.5, Cxcl13, and Ccr7 were significantly expressed in the MLN anlage, but the expression level of Ccl21 was low. The expression level of Cxcl13, Ccr7, and Ccl21 in MLN were significantly increased at 2 w after birth (P < 0.05), while the expression of Ccr7 and Ccl21 were significantly decreased at 6 w after birth (P < 0.05).

CONCLUSIONAdipocyte progenitor cells are involved in the rat MLNs development through differentiation into FRC and FDC. The expression of the relevant chemokines during the development of MLNs is dynamic and may be related to the maintenance of lymph nodes self-balance state.

Animals ; Chemokines ; genetics ; metabolism ; Female ; Gene Expression Regulation, Developmental ; physiology ; Intercellular Signaling Peptides and Proteins ; genetics ; metabolism ; Lymph Nodes ; embryology ; metabolism ; Membrane Proteins ; genetics ; metabolism ; Mesentery ; embryology ; Pregnancy ; Rats

OBJECTIVETo bioinformatically predict and analyze target genes of miRNA-126(*), with the aim of providing certain basis for related research about target genes and regulatory mechanism in the future.

METHODSThe miRNA chip technology was applied to measure expression levels of miRNA-126(*) in 3 time points (embryo 16, 19 and 21 days) of fetal lung development. Then the target genes of miRNA-126(*) were screened through miRGen2.0 database. Subsequent bioinformatic analysis of these target genes was performed by Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes Pathway analysis (KEGG Pathway analysis).

RESULTSmiRNA-126(*) manifested continuously upregulated expression with the lung development (from embryo 16 to 21 days). There were 422 predicted target genes in total, and the gene set mainly located in glucuronosyltransferase activity, transferase activity (GO molecular function), multicellular organismal development, developmental process (GO biology process) and intracellular part (GO cellular component). The KEGG Pathway analysis demonstrated that the gene set mostly located in RNA degradation (signal transduction pathway) and prion diseases (disease pathway).

CONCLUSIONSThe results suggest that miRNA-126(*) plays a certain role in fetal lung development and provide a basis for lung development research in the future.

Animals ; Computational Biology ; Female ; Glucuronosyltransferase ; metabolism ; Lung ; embryology ; Male ; MicroRNAs ; physiology ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; physiology

BACKGROUNDThere have been no detailed reports of the three-dimensional structure and the relationship between the external and internal vascularizations observed successively for a long duration in the rat fetus, although many authors have studied the vascular morphology of the developing brain. This study examined the three-dimensional structure of both the external and internal vascularizations of the prenatal rat telencephalon from embryonic days 12 (E12) to 20 (E20).

METHODA microvascular casting method for scanning electron microscopy (SEM) was used in this study, along with vascular staining using gold-gelatin solution-autometallography (GGS-AMG) after intravascular injection of colloidal gold, as well as hematoxylin-eosin (HE) staining for paraffin embedded specimens.

RESULTSIn GGS-AMG stains, E16 fetuses had a few short perforating cortical blood vessels (SPCVs); E17 fetuses had long perforating cortico-medullary vessels (LPCVs). Older fetuses had specific patterns of vascular networks in the cortex and the deeper subcortical part of the telencephalon. In the cortex, fine longitudinal blood vessels were connected by transverse channels. The deep telencephalon had fine blood vessels running in all directions. Using SEM, the external vascularization was already visible in E12 fetuses as arborizations of arterial branches, forming a mesh of fine vascular networks covering the telencephalon. A coralliform fine venous plexus was observed in the external vascularization of E16 fetuses. There were ring-like anastomoses and bud-like protrusions in the network of small blood vessels, most likely the angiogenesis of fetal vessels. From E12 to E16, an immature and incomplete internal vascularization began to appear. There were short blood vessels with ballooned terminals branching from the external vascularization. They penetrated the brain tissue to form networks in the superficial layer, comparable to SPCVs. In E17 to E20 fetuses, tortuous venous branches, straight arterial blood vessels, and a fine network of small blood vessels formed the external vascularization. There were fewer arterial than venous branches connecting to the fine networks of small blood vessels. LPCVs were noted at E17, at the time the white matter emerged. They branched from the external vascularization, and perpendicularly penetrated the brain surface, traversing the cortical plate, and entering into the deep brain. At E17, arterial and venous blood vessels could be clearly distinguished in the external vascularization. At E20, the cortex and white matter contained specific arrangements of networks of fine blood vessels, as seen by GGS-AMG staining.

CONCLUSIONThese findings show that the development of both the external and internal vascularization follows the development of the telencephalon. In particular, the emergence of the cortical plate and white matter on E16 and E17 influence the development of both the internal and the external vascularization. The laminal arrangement of blood vessels was not observed corresponding to the respective laminal neuronal layers.

Animals ; Blood Vessels ; embryology ; ultrastructure ; Embryo, Mammalian ; Fetus ; Microscopy, Electron, Scanning ; Rats ; Rats, Wistar ; Telencephalon ; blood supply

OBJECTIVETo investigate the expression and role of miRNA-126/miRNA-126(*) in the fetal lung development of rats.

METHODSTwelve pregnant Sprague-Dawley rats were randomly divided into 3 groups and the fetal rats were removed at 16, 19 and 21 days of gestation respectively. Hematoxylin and eosin staining was performed to observe lung morphology of fetal rats. Then microRNA (miRNA) microarray was used to study the expression patterns of miRNA-126/miRNA-126(*) in fetal lungs at the three time points. And miRNA-126(*) was selected for further study by real-time PCR.

RESULTSThere was no evident difference in the expression of miRNA-126 among the three groups, however the expression level of miRNA-126(*) increased gradually as the fetal lung developed. The real-time PCR result further showed that expression of miRNA-126(*) increased gradually with lung development, displaying significant differences among the three groups (P<0.05).

CONCLUSIONSmiRNA-126(*) may play an important role in development of the fetal lung in rats.

Animals ; Female ; Lung ; embryology ; Male ; MicroRNAs ; analysis ; physiology ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction

OBJECTIVETo investigate whether there is neogenesis of myelin sheath and neuron after transplantation of Schwann cells into cerebral hemorrhage lesion.

METHODSSchwann cells were expanded, labeled with BrdU in vitro and transplanted into rat cerebral hemorrhage with blood extracted from femoral artery and then injected into the basal nuclei. Double immunohistochemistry staining and electron microscopy were used to detect the expression of BrdU/MBP and BrdU/GAP-43 and remyelination.

RESULTSBrdU/MBP double positive cells could be seen at 1 week up to 16 weeks after transplantation of Schwann cells. Thin remyelination was observed under electron microscope. GAP-43 positive cells appeared after 12 weeks and were found more in Hippocamp.

CONCLUSIONSGrafted Schwann cells participate in remyelination and promoter nerve restore in rat cerebral hemorrhage.

Animals ; Cerebral Hemorrhage ; metabolism ; therapy ; GAP-43 Protein ; metabolism ; Rats ; Rats, Wistar ; Schwann Cells ; metabolism ; transplantation ; Sciatic Nerve ; cytology ; embryology