BACKGROUNDEpidermal growth factor (EGF), a mitogenic polypeptide that binds to cell surface receptors, is an important regulator of cell differentiation and fetal lung surfactant synthesis. We investigated the preventive and therapeutic effects of EGF in respiratory distress syndrome, by administering EGF and dexamethasone (Dex) to mother rat before delivery.

METHODSSix female Sprague-Dawley (SD) rats were assigned to three groups (2 rats each); EGF or Dex was given to pregnant rats (EGF group and Dex group, respectively) from gestational day 16 to day 18 by intraperitoneal injection, while the group with normal saline injection was used as negative controls. Fetal rats were taken out of womb by hysterotomy on day 19 of pregnancy, then 24 fetal rats were randomly chosen from each group. Their body weights were measured, and pulmonary surfactant protein-A and -B (SP-A and SP-B) antigens were determined by immunohistochemical staining in each group. The histologic structure was examined under a light microscope, a light microscopic image system or an electron microscope.

RESULTSThe expressions of SP-A and SP-B could be detected in each group. A significant difference was observed for SP-A and SP-B in the EGF and Dex groups compared with the control group (P < 0.01). Image analysis showed that the relative values of air space area and interalveolar septa area in the EGF and Dex groups were significantly greater than those in the control group (P < 0.01), while no significant difference was found between the two groups (P > 0.05). The ultrastructural features of fetal lungs showed that the number of alveolar type II cells containing lamellar bodies in the EGF and Dex groups was apparently increased compared with that in the control group. The mean body weight of fetus from the Dex group was smaller than that from the control group ((1.3192 +/- 0.0533) g, (1.3863 +/- 0.0373) g), but there was no significant difference between the EGF group and the control group ((1.3986 +/- 0.0730) g, (1.3863 +/- 0.0373) g).

CONCLUSIONSMaternal treatment with EGF and Dex on days 16 - 18 of gestation could promote morphogenesis and increase the surfactant levels in premature fetal lung. However, maternal treatment with Dex, not EGF, decreased the body weight.

Animals ; Dexamethasone ; pharmacology ; Epidermal Growth Factor ; pharmacology ; Female ; Immunohistochemistry ; Lung ; drug effects ; embryology ; ultrastructure ; Microscopy, Electron, Transmission ; Pregnancy ; Pulmonary Surfactant-Associated Protein A ; metabolism ; Pulmonary Surfactant-Associated Protein B ; metabolism ; Rats ; Rats, Sprague-Dawley

BACKGROUNDThe two most basic properties of mesenchymal stem cells (MSCs) are the capacities to self-renew indefinitely and differentiate into multiple cells and tissue types. The cells from human umbilical cord Wharton's Jelly have properties of MSCs and represent a rich source of primitive cells. This study was conducted to explore the possibility of inducing human umbilical cord Wharton's Jelly-derived MSCs to differentiate into nerve-like cells.

METHODSMSCs were cultured from the Wharton's Jelly taken from human umbilical cord of babies delivered after full-term normal labor. Salvia miltiorrhiza and beta-mercaptoethanol were used to induce the human umbilical cord-derived MSCs to differentiate. The expression of neural protein markers was shown by immunocytochemistry. The induction process was monitored by phase contrast microscopy, electron microscopy (EM), and laser scanning confocal microscopy (LSCM). The pleiotrophin and nestin genes were measured by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTSMSCs in the Wharton's Jelly were easily attainable and could be maintained and expanded in culture. They were positive for markers of MSCs, but negative for markers of hematopoietic cells and graft-versus-host disease (GVHD)-related cells. Treatment with Salvia miltiorrhiza caused Wharton's Jelly cells to undergo profound morphological changes. The induced MSCs developed rounded cell bodies with multiple neurite-like extensions. Eventually they developed processes that formed networks reminiscent of primary cultures of neurons. Salvia miltiorrhiza and beta-mercaptoethanol also induced MSCs to express nestin, beta-tubulinIII, neurofilament (NF) and glial fibrillary acidic protein (GFAP). It was confirmed by RT-PCR that MSCs could express pleiotrophin both before and after induction by Salvia miltiorrhiza. The expression was markedly enhanced after induction and the nestin gene was also expressed.

CONCLUSIONSMSCs could be isolated from human umbilical cord Wharton's Jelly. They were capable of differentiating into nerve-like cells using Salvia miltiorrhiza or beta-mercaptoethanol. The induced MSCs not only underwent morphologic changes, but also expressed the neuron-related genes and neuronal cell markers. They may represent an alternative source of stem cells for central nervous system cell transplantation.

Cell Differentiation ; Cells, Cultured ; Glial Fibrillary Acidic Protein ; analysis ; Humans ; Immunohistochemistry ; Mesenchymal Stromal Cells ; cytology ; Neurofilament Proteins ; analysis ; Neurons ; cytology ; Reverse Transcriptase Polymerase Chain Reaction ; Tubulin ; analysis ; Umbilical Cord ; cytology