AIM： To investigate the mechanism behind β-cell regeneration in neonatal rat pancreas treated with strep- tozotocin （STZ）. METHODS： Neonatal Sprague Dawley rats were intra- peritoneally injected with 70 mg/kg STZ...AIM： To investigate the mechanism behind β-cell regeneration in neonatal rat pancreas treated with strep- tozotocin （STZ）. METHODS： Neonatal Sprague Dawley rats were intra- peritoneally injected with 70 mg/kg STZ. Body weight, pancreas weight and blood glucose were recorded every two days after the treatment. To identify the expression and location of transcription factors in the rat pancreas, double immunofluorescent staining was performed using antibodies to specific cell markers and transcription factors. RESULTS： Expression of Neurogenin 3 （Ngn3）, a marker for endocrine precursor cells, was observed by immunofluorescence in a few β-cells and many a-cells. The expression reached a peak 12 d after treatment. Pax4, a transcription factor that lies downstream of Ngn3 and plays an important role in β-cell differentiation, was also expressed in the α-cells of STZ-treated rats. We did not observe significant changes in Nkx6.1, which is essential for β-cell maturation in the treated rats. CONCLUSION： α-cells dedifferentiated into endocrine precursor cells and acquired the ability to dedifferentiate in the neonatal rat pancreas after STZ treatment.展开更多
Background Liraglutide is glucagon-like peptide-1 receptor agonist for treating patients with type 2 diabetes mellitus. Our previous studies have demonstrated that liraglutide protects cardiac function through improvi...Background Liraglutide is glucagon-like peptide-1 receptor agonist for treating patients with type 2 diabetes mellitus. Our previous studies have demonstrated that liraglutide protects cardiac function through improving endothelial function in patients with acute myocardial infarction undergoing percutaneous coronary intervention. The present study will investigate whether liraglntide can perform direct protective effects on cardiomyocytes against reperfusion injury. Methods In vitro experiments were performed using H9C2 cells and neonatal rat ventricular cadiomyocytes undergoing simulative hypoxia/reoxygenation （H/R） induction. Cardiomyocytes apoptosis was detected by fluorescence TUNEL. Mitochondrial membrane potential （AWm） and intracellular reactive oxygen species （ROS） was assessed by JC-1 and DHE, respectively. Fura-2/AM was used to measure intracellular Ca2＋ concentration and calcium transient. Immtmofluorescence staining was used to assess the expression level of sarcoplasmic reticulum Ca2＋-ATPase （SERCA2a）. In vivo experiments, myocardial apoptosis and expression of SERCA2a were detected by colorimetric TUNEL and by immunofluorescence staining, respectively. Results In vitro liraglutide inhibited cardiomyotes apoptosis against H/R. △mψ of cardiomyocytes was higher in liraglntide group than H/R group. H/R increased ROS production in H9C2 cells which was attenuated by liraglutide. Liraglutide significantly lowered Ca2＋ overload and improved calcium transient compared with H/R group, lmmunofluorescence staining results showed liraglutide promoted SERCA2a expression which was decreased in H/R group. In ischemia/reperfusion rat hearts, apoptosis was significantly attenuated and SERCA2a expression was increased by liraglutide compared with H/R group. Conclusions Liraglutide can directly protect cardiomyocytes against reperfusion injury which is possibly through modulation of intracellular calcium homeostasis.展开更多
Objective To acquire oval cells （progenitor stem cells ） from adult rat liver of different models including diabetic rats. Methods Thirty Sprague-Dawley （ SD ） rats were divided into 5 groups randomly： control, 2...Objective To acquire oval cells （progenitor stem cells ） from adult rat liver of different models including diabetic rats. Methods Thirty Sprague-Dawley （ SD ） rats were divided into 5 groups randomly： control, 2-acetylaminofluorene （ 2-AAF ）, 2-AAF ＋ partial hepatectomy （ PH ）, 2-AAF ＋ carbon tetrachloride （ CCl4 ）, and diabetic groups. As two-step collagenase perfusion protocol of Seglen, oval cells were isolated by Percoll density gradient centrifugation. Thy1. 1 positive cells were sorted by flow cytometry, and then cultured in Dulbecco＇s minimum Eagle＇s medium （DMEM）. Immunofluorescence staining was applied to labelling Thyl. 1. Results Different rates of Thy1.1 positive oval cells were found in different rat model groups ： 0. 5 % in 2-AAF, 0. 3% in 2-AAF ＋ PH, 0. 2% in 2-AAF ＋ CCl4, 0. 1% in diabetic, and 0. 0% in control. Isolated cells adhered to plate with fusiform or polygon as epithelial cells. Conclusion Progenitor stem cells exist in injured liver tissue including those from diabetic rats.展开更多
Objective： To observe p21-activated kinase 6 （PAK6） expression and its possible role after spinal cord injury （SCI） in adult rat.Methods： Sprague-Dawley rats were subjected to spinal cord injury. To explore the ...Objective： To observe p21-activated kinase 6 （PAK6） expression and its possible role after spinal cord injury （SCI） in adult rat.Methods： Sprague-Dawley rats were subjected to spinal cord injury. To explore the pathological and physiological significance of PAK6, the expression patterns and distribution of PAK6 were observed by Western blot, immunohistochemistry and immunofluorescence.Results： Western blot analysis showed PAK6 protein level was significantly up-regulated on day 2 and day 4,then reduced and had no up-regulation till day 14. Immunohistochemistry analysis showed that the expression of PAK6 was significantly increased on day 4 compared with the control group. Besides, double immunofluorescence staining showed PAK6 was primarily expressed in the neurons and astrocytes in the control group. While after injury, the expression of PAK6 was increased significantly in the astrocytes and neurons, and the astrocytes were largely proliferated. We also examined the expression of proliferating cell nuclear antigen （PCNA） and found its change was correlated with the expression of PAK6. Importantly, double immunofluorescence staining revealed that cell proliferation evaluated by PCNA appeared in many PAK6-expressing cells on day 4 after injury.Conclusion： The up-regulation of PAK6 in the injured spinal cord may be associated with glial proliferation.展开更多
基金Supported by The National Natural Science Foundation of China,No. 81070620
文摘AIM： To investigate the mechanism behind β-cell regeneration in neonatal rat pancreas treated with strep- tozotocin （STZ）. METHODS： Neonatal Sprague Dawley rats were intra- peritoneally injected with 70 mg/kg STZ. Body weight, pancreas weight and blood glucose were recorded every two days after the treatment. To identify the expression and location of transcription factors in the rat pancreas, double immunofluorescent staining was performed using antibodies to specific cell markers and transcription factors. RESULTS： Expression of Neurogenin 3 （Ngn3）, a marker for endocrine precursor cells, was observed by immunofluorescence in a few β-cells and many a-cells. The expression reached a peak 12 d after treatment. Pax4, a transcription factor that lies downstream of Ngn3 and plays an important role in β-cell differentiation, was also expressed in the α-cells of STZ-treated rats. We did not observe significant changes in Nkx6.1, which is essential for β-cell maturation in the treated rats. CONCLUSION： α-cells dedifferentiated into endocrine precursor cells and acquired the ability to dedifferentiate in the neonatal rat pancreas after STZ treatment.
基金This work is supported by grants from National Natural Science Foundation of China （No. 81102079） and China Postdoctoral Science Foundation （No. 201003776）. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors report no conflict of interest. The authors are responsible for the content and writing of the paper.
文摘Background Liraglutide is glucagon-like peptide-1 receptor agonist for treating patients with type 2 diabetes mellitus. Our previous studies have demonstrated that liraglutide protects cardiac function through improving endothelial function in patients with acute myocardial infarction undergoing percutaneous coronary intervention. The present study will investigate whether liraglntide can perform direct protective effects on cardiomyocytes against reperfusion injury. Methods In vitro experiments were performed using H9C2 cells and neonatal rat ventricular cadiomyocytes undergoing simulative hypoxia/reoxygenation （H/R） induction. Cardiomyocytes apoptosis was detected by fluorescence TUNEL. Mitochondrial membrane potential （AWm） and intracellular reactive oxygen species （ROS） was assessed by JC-1 and DHE, respectively. Fura-2/AM was used to measure intracellular Ca2＋ concentration and calcium transient. Immtmofluorescence staining was used to assess the expression level of sarcoplasmic reticulum Ca2＋-ATPase （SERCA2a）. In vivo experiments, myocardial apoptosis and expression of SERCA2a were detected by colorimetric TUNEL and by immunofluorescence staining, respectively. Results In vitro liraglutide inhibited cardiomyotes apoptosis against H/R. △mψ of cardiomyocytes was higher in liraglntide group than H/R group. H/R increased ROS production in H9C2 cells which was attenuated by liraglutide. Liraglutide significantly lowered Ca2＋ overload and improved calcium transient compared with H/R group, lmmunofluorescence staining results showed liraglutide promoted SERCA2a expression which was decreased in H/R group. In ischemia/reperfusion rat hearts, apoptosis was significantly attenuated and SERCA2a expression was increased by liraglutide compared with H/R group. Conclusions Liraglutide can directly protect cardiomyocytes against reperfusion injury which is possibly through modulation of intracellular calcium homeostasis.
基金Supported by Shanghai Municipal Education Commission Key Project (07ZZ35)
文摘Objective To acquire oval cells （progenitor stem cells ） from adult rat liver of different models including diabetic rats. Methods Thirty Sprague-Dawley （ SD ） rats were divided into 5 groups randomly： control, 2-acetylaminofluorene （ 2-AAF ）, 2-AAF ＋ partial hepatectomy （ PH ）, 2-AAF ＋ carbon tetrachloride （ CCl4 ）, and diabetic groups. As two-step collagenase perfusion protocol of Seglen, oval cells were isolated by Percoll density gradient centrifugation. Thy1. 1 positive cells were sorted by flow cytometry, and then cultured in Dulbecco＇s minimum Eagle＇s medium （DMEM）. Immunofluorescence staining was applied to labelling Thyl. 1. Results Different rates of Thy1.1 positive oval cells were found in different rat model groups ： 0. 5 % in 2-AAF, 0. 3% in 2-AAF ＋ PH, 0. 2% in 2-AAF ＋ CCl4, 0. 1% in diabetic, and 0. 0% in control. Isolated cells adhered to plate with fusiform or polygon as epithelial cells. Conclusion Progenitor stem cells exist in injured liver tissue including those from diabetic rats.
文摘Objective： To observe p21-activated kinase 6 （PAK6） expression and its possible role after spinal cord injury （SCI） in adult rat.Methods： Sprague-Dawley rats were subjected to spinal cord injury. To explore the pathological and physiological significance of PAK6, the expression patterns and distribution of PAK6 were observed by Western blot, immunohistochemistry and immunofluorescence.Results： Western blot analysis showed PAK6 protein level was significantly up-regulated on day 2 and day 4,then reduced and had no up-regulation till day 14. Immunohistochemistry analysis showed that the expression of PAK6 was significantly increased on day 4 compared with the control group. Besides, double immunofluorescence staining showed PAK6 was primarily expressed in the neurons and astrocytes in the control group. While after injury, the expression of PAK6 was increased significantly in the astrocytes and neurons, and the astrocytes were largely proliferated. We also examined the expression of proliferating cell nuclear antigen （PCNA） and found its change was correlated with the expression of PAK6. Importantly, double immunofluorescence staining revealed that cell proliferation evaluated by PCNA appeared in many PAK6-expressing cells on day 4 after injury.Conclusion： The up-regulation of PAK6 in the injured spinal cord may be associated with glial proliferation.
