Objective:To investigate the effects of hyperglycemia on the pancreas and duodenal homeobox gene-1 (Pdx-1) and insulin gene in fetal rat islets in vitro.Methods:Fetal rat islets were digested by collagenase and underwent culture at 5.5 mmol/L, 11.1 mmol/L and 33.3 mmol/L glucose concentration respectively.The insulin content of fetal rat islets and insulin releasing test were measured by radioimmunoassay.The expression of Pdx-1 protein and mRNA were evaluated by indirect immunofluorescence cytochemistry staining and reverse transcriptase-polymerase chain reaction (RT-PCR).Results:The results showed that the insulin content and stimulated index of hyperglycemia group 1 ( 11.1 mmol/L) were significantly higher than that of controls ( 5.5 mmol/L) and hyperglycemia group 2 ( 33.3 mmol/L).The majority of Pdx-1 positive cells in control group were confined to the nuclear periphery, but the majority of Pdx-1 positive cells in hyperglycemia groups were translocated to the nucleoplasm, and the expression of Pdx-1 mRNA was also elevated in hyperglycemia groups.However,the expression of insulin mRNA decresed in hyperglycemia group 2.Conclusion:Hyperglycemia may regulate Pdx-1 in fetal rat islets by increasing its protein level and translocation to the nucleus.

Alzheimer disease (AD) is a fatal neurodegenerative disorder,and the most common cause of dementia in the elderly.Accumulated evidences in AD research suggest that alterations in the microRNA (miRNA) network could contribute to risk for the disease.As the second discovered miRNA,Let-7 has an important effect on cell proliferation,differentiation,apoptosis,immune response,tumorigenesis,metastasis,and so on.We review in this article the role of Let-7 family in the pathogenesis of AD to provide a strong basis for future research aimed at understanding the potential contribution of miRNAs to AD pathophysiology.

Objective To identify the effect of decreasing the rejection using the biological semipermeable membrane combined with the privileged site xenotransplantation. Methods The rat ICCs encapsulated by biological semipermeable membrane were xenotransplanted into dog's brain. The pathological changes of implants and surrounding cerebral tissues were observed under light and electric microscopy. The ?-cells of implants were identified by immunohistochemistry. Results After 2 months of transplantation, The ?-cells were observed and the lymphocytes were dispersed in the grafts.The brain tissues near the grafts showed slight edema and glial hyperplasia. Conclusion The method using the biological semipermeable membrane in combination with the privileged site xenotransplantation have a beneficial effect on the inhibition of the rejection of heterogeneous ICCs implant.

AIM: To study the protocol and condition that induce bone marrow stromal cells (MSCs) to differentiate into neuron in vitro by baicalin, a kind of flavonoid isolated from an important medicinal plant Scutellariae Radix . METHODS: MSCs from adult rats were induced by baicalin in serum-free medium for 6 h, and postinduced for 6 d. The morphological changes of MSCs were evaluated by light microscope. The positive percentages of neuron-specific enolase (NSE), 200-kilodalton neurofilament (NF), glial fibrillary acidic protein (GFAP) and vimentin expression were measured by immunocytochemistry with ABC staining. Hoechst 33258 staining was used to measure the cell viability by fluorescence microscope. RESULTS: After induction for 6 d, MSCs displayed neuronal morphologies, such as pyramidal cell bodies and processes formed extensive networks. The positive percentages of NSE, NF, GFAP and vimentin protein expression were 70.5%?11.6%, 68.3%?13.4% ,

BACKGROUND:Currently, what we know about exosomes is that it can be produced by a variety of cel s and transfer a variety of materials, producing subsequent function of regulation.
OBJECTIVE:To review the function of exosomes in mesenchymal stem cel differentiation, in order to provide reference for further in-depth study.
METHODS:With the key words of“exosome, mesenchymal stem cel , differentiation”in Chinese and English, respectively, a computer-based search was performed for articles published in CNKI, Medline and Embase databases from January 2001 to September 2016. After the initial screening, the reserved articles were further detailed, summarized and concluded.
RESULTS AND CONCLUSION:Exosomes are a kind of vesicles 40-100 nm in diameter, which can be secreted by a variety of cel types, containing functional products, such as functional protein, gene product, lipid and so on. As a bridge of adjacent cel s transferring functional products, exosomes are becoming an issue of concern in the microenvironment for cel interaction. In the differentiation of mesenchymal stem cel s, exosomes also play an indispensable role via pathway regulation.

Objective To investigate changes in the expression of prepro-orexin and orexin receptor-1 ( OX1R) following permanent middle cerebral artery occlusion ( MCAO ) with or without preconditioning through electrical stimulation of the cerebellar fastigial nucleus (FNS). Methods Wistar rats were subjected to permanent MCAO and randomly divided into 5 groups: a sham-operated control group (PO), an FNS preconditioning + shamoperated control group (FNS-PO) , an ischemia group, an FNS preconditioning + ischemia group (FNS-PI) and a cerebellar fastigial nucleus injury + FNS preconditioning + ischemia group (FNL-FNS-PI). Each group was divided into 5 subgroups according to the time at which the animals were sacrificed after the MCAO ( 1, 3, 6, 12 and 24 h).RT-PCR was used to detect expression of OX1R mRNA, and ELISA to measure the levels of orexin-A in the hypothalamus and plasma. Results The immunoreactivity of prepro-orexin decreased significantly in the PI groups, with further decreases over time. At the 12th h after MCAO, the immunoreactivity of prepro-orexin reached a minimum.There were significant differences between the rats in the PO and FNS-PO groups. On the contrary, the immunoreactivity of OX1R increased significantly in the PI groups, with further increases continuing over time, peaking at 12 h after the MCAO. There were significant differences between the PO and FNS-PO groups. In the rats with FNS preconditioning (PI-FNS) , the decrease in prepro-orexin and the increase in OX1R were significantly inhibited compared to the PI subgroups at the 6th and 12th hour. There was no significant difference between the FNL-PIFNS group and the PI group. The expression of OX1R mRNA increased significantly in the PI group, with further increases continuing over time, peaking at 24 hours. The plasma levels of orexin-A were not significantly different among the groups, but the levels of orexin-A in the hypothalamus decreased significantly in the PI and FNL-PI-FNS groups, with further decreases continuing over time. At the 12th h after the MCAO the levels were significantly different compared with the PO and PO-FNS groups. While in the rats with FNS preconditioning (PI-FNS) , the decrease in orexin-A level was reversed and there was no significant difference compared with PO and PO-FNS groups. Conclusions The orexinergic system is altered following cerebral ischaemia. FNS preconditioning may be able to regulate these changes.

Bone marrow mesenchymal stem cells (BMSCs),which can be isolated from organs and tissues,are cell populations with high degree of plasticity,similar to hematopoietic stem cells in bone marrow,and can be in vitro cultured,induced and amplified.BMSCs are increasingly used in gene therapy,cell therapy and tissue engineering.BMSCs have been currently studied in a number of autologous transplantations,while not all BMSCs are suitable for autologous transplantation.BMSCs exhibit biological aging gradually when cultured in vitro.Biological aging can be divided into age-induced senescence and long-term passage induced senescence.Aging BMSCs demonstrate changes in biological behaviour which reduces the success rate of autologous transplantation.In this review,biological aging BMSCs are discussed in order to provide help for the transplantation of BMSCs.

AIM: To investigate whether grafting neural stem cells (NSCs) improves the impaired cognitive deficits and spatial recognition after ischemic-hypoxic brain damage (HIBD) in neonatal rats. METHODS: Non-immunosuppressed 7-day-old SD rats were used as research subject and randomly divided into 3 groups: (1) sham group (n=10); (2) HIBD group (n=11); (3) transplant group (n=13). (2) and (3) were anesthetized and subjected to a hypoxic/ischemic injury obtained by combination of left carotid ligation and exposure to 8% oxygen for 2 h. At 3 days post injury, hypoxic-ischemic brain damaged animals were re-anesthetized and randomized to receive stereotactic injection of NSCs prelabeling with BrdU or control media into the hippocampus in the ipsilateral hemisphere. Cognitive (i.e., learning) deficits were assessed at 2 to 4 weeks after transplantation. At the end of the behavioral tests, the animals were killed and evaluated for NSC survival and histopathological analysis. RESULTS: Transplant group showed significantly improved cognitive function in selected tests as compared with HIBD group during the 4-week observation period. They took less time than HIBD group in finding the 3 arms baited with water and had a decreased number of working and reference memory errors in radial maze acquisition tests. Histological analysis showed that transplanted NSCs attenuated CA1 cell loss after HIBD, and NSCs survived for as long as 4 weeks after transplantation and were detected in the hippocampus. CONCLUSION: These data suggest that transplanted NSCs attenuate brain damage and cognitive dysfunction after hypoxic-ischemic brain damage. This approach warrants continued investigation in light of potential therapeutic uses.

Objective To investigate a new method of a long term culture for rat islets in vitro. Methods Rat islets marked by green fluorescent protein (GFP) were cocultured with Sertoli cell for 20 weeks. Histological studies were performed on islet group and coculture group in 1w, 3w, 10w, 15w, 20w of culture by light, fluorescent and electron microscopy. Insulin released was measured by radioimmunoassay. Results In islet group, islet viability and the number of insulin positive cells were significantly decreased after 3w of culture, cumulative quantities of insulin for 24 hours and the stimulation index also fell rapidly under this condition, meanwhile the ultrastructure of islets was destroyed. However, under coculture condition, culture time of islets was prolonged in vitro, islet viability and the number of insulin positive cells were significantly increased, cumulative quantities of insulin for 24 hours and the stimulation index maintained at high level, and the ultrastructure of islets remained normal even after 20w of culture. Conclusion Coculture of rat islets with Sertoli cells may promote islet growth and prolong culture time, and it is a new method of a long term culture of islets in vitro.

AIM:To construct a eukaryotic expression vector containing pancreatic duodenal homebox-1(PDX-1)and to elevate the expression efficiency of exogenous gene in rat bone marrow mesenchymal stem cells(MSCs).METHODS:Recombinant vector containing PDX-1 was constructed.Flow cytometry was used to identify the cell cycle of bone marrow mesenchymal stem cells(MSCs)cultured in vitro.Recombinant vector containing PDX-1 was transfected into bone marrow MSCs using superfect in medium.After being selected by G418,RT-PCR and Western blotting were used to investigate the expression of PDX-1 in MSCs.RESULTS:Restricted enzyme analysis and sequencing showed that PDX-1 gene segment was consistent with that in GenBank.Flow cytometry showed that there were about 85.9% cells at the cell cycle of G_0/G_1.The whole cells transfected emitted green fluorescence under flow cytometry.The efficiency of transfection was above 40%.RT-PCR and Western blotting demonstrated that there was expression of PDX-1 in transfected bone marrow MSCs.CONCLUSION:Recombinant vector containing PDX-1 was constructed successfully.Superfect mediated expression of exogenous gene in bone marrow MSCs in a high efficiency,and bone marrow MSCs containing exogenous gene are an ideal cells for gene therapy.