ABSTRACT
Objective To investigate the protective effects of N-acetyl-L-tryptophan (L-NAT) on intestinal damage after rat hepatic ischemia reperfusion.Methods Twenty-four healthy adult rats were divided into the sham operation group (Sham),ischemia reperfusion group (IR),ischemia reperfusion and N-acetyl-L-tryptophan group(IR+L-NAT).The hepatic ischemia reperfusion model was established by occluding the afferent vessels of the left and middle lobes.The morphological structures of the small intestine were observed by hematoxylin-eosin (HE) staining.The expressions of active caspase-3,Bax and Bcl-2 were detected by immunohistochemistry staining.Results (1) In the IR group,the structure of intestinal villis was destroyed,the intestinal mucosa showed congestion and exfoliation,the epithelial cells had degeneration and necrosis,and infiltration of inflammatory cells appeared;which could be alleviated by L-NAT.(2)The immunohistochemistry showed that compared with the Sham group,the expression of active caspase-3,Bcl-2 and Bax in the IR group was increased,after L-NAT intervention,the Bax and caspase-3 expression was decreased,while the Bcl-2 expression was further increased.Conclusion L-NAT could inhibit the apoptosis of small intestinal epithelial cells caused by liver ischemic reperfusion and attenuates intestinal epithelial damage.
ABSTRACT
Objective To investigate the protective effects of N-acetyl-L-tryptophan (L-NAT) on intestinal damage after rat hepatic ischemia reperfusion.Methods Twenty-four healthy adult rats were divided into the sham operation group (Sham),ischemia reperfusion group (IR),ischemia reperfusion and N-acetyl-L-tryptophan group(IR+L-NAT).The hepatic ischemia reperfusion model was established by occluding the afferent vessels of the left and middle lobes.The morphological structures of the small intestine were observed by hematoxylin-eosin (HE) staining.The expressions of active caspase-3,Bax and Bcl-2 were detected by immunohistochemistry staining.Results (1) In the IR group,the structure of intestinal villis was destroyed,the intestinal mucosa showed congestion and exfoliation,the epithelial cells had degeneration and necrosis,and infiltration of inflammatory cells appeared;which could be alleviated by L-NAT.(2)The immunohistochemistry showed that compared with the Sham group,the expression of active caspase-3,Bcl-2 and Bax in the IR group was increased,after L-NAT intervention,the Bax and caspase-3 expression was decreased,while the Bcl-2 expression was further increased.Conclusion L-NAT could inhibit the apoptosis of small intestinal epithelial cells caused by liver ischemic reperfusion and attenuates intestinal epithelial damage.
ABSTRACT
Background The retina ischemia reperfusion injury (RIRI) can lead to apoptosis,which is associated with many genes.It is very significant to explore the protection of drugs on RIRI-induced apoptosis.Objective This study was to explore the relationship between the expression of Nogo-A and the cell apoptosis as well as the therapeutic effect of NEP1-40 in RIRI retina.Methods The device of raising intraocular pressure (IOP)was used to elevate the IOP for 60 minutes and then restore the IOP to normal for the establishment of RIRI models.Seventy-eight SD rats were randomized to the normal group,RIRI group and NEP1-40 group.PBS of 5 ml/(kg · d)was injected intraperitoneally in the rats of the RIRI group,and NEP1-40 of 8 mg/(L · kg) was used in the same way in the NEP1-40 group.The rats were sacrificed in overdose anesthesia at 6 hours,12 hours and 1 day,2,3,7 days after RIRI to prepare the retinal specimens.The ultrastructure of rat retinas was examined under the transmission electron microscope.Cell apoptosis was assessed by the TUNEL method,and the apoptotic index (AI) was calculated.The expressions of Nogo-A protein and mRNA in rat retinas were detected by immunohistochemistry and semiquantitative reverse transcription PCR (RT-PCR).Results The ultrastructure of retinal cells were normal in the normal group.Retinal cell organelle dissolution,mitochondria swelling,cavitation,chromatin edge heterochromatin and apoptotic body were seen in the rats of the RIRI group from 12 hours through 7 days after injection.However,only the slight loose of outer membranous disk,inner and outer nuclear layer and retinal ganglion cells,the nucleus gap broadening,shortness of some mitochondrial cristae in the NEP1-40 group.TUNEL-positive cells appeared 6 hours after RIRI and reached peak in 1 day,and gradually declined after that in the RIRI group.A similar pattern was seen in the rats of the NEP1-40 group with a more mild manifestation.Significant differences were seen in the AI values among the different groups at various time points (Fgroup =100.850,P =0.000 ; Ftime =34.309,P =0.000),and the AI values were significantly higher in the RIRI group and NEP1-40 group compared with normal group;while the AI values in the NEP1-40 group was lower than those of the RIRI group (all at P＜0.05).The expressions of Nogo-A protein and mRNA showed a coincident pattern with apoptosis procedure,with a gradually elevated level from 6 hours through 7 days after RIRI and a peak in 2 days,and those in the NEP1-40 group were weaker in comparison with the RIRI group in various time points.Significant differences were detected in the expression of Nogo-A protein and the expression of Nogo-A mRNA among different groups and various time points(protein:Fgroup =164.139,P =0.000;Ftime =21.772,P =0.000.mRNA:Fgroup =93.889,P =0.000 ; Ftime =6.349,P =0.000).Conclusions Nogo-A probably plays an important role in RIRI.NEP1-40 can protect retinal cells from apoptosis following RIRI through down-regulating the expression of Nogo-A.
ABSTRACT
Objective: To investigate the expression of ATP-Binding Cassette Proteins including P-gp (P-glycoprotein), MRP1 (multidrug resistance associated protein 1) and BCRP (breast cancer resistance protein) in hepatocellular carcinoma and its relationship with pathological features. Methods: The expression of P-gp/MDR1 (multidrug resistance gene 1), MRP1 and BCRP in hepatocellular carcinoma was examined by RT-PCR and immunohistochemistry in 34 cases of hepatocellular carcinoma and 19 cases of paraneoplastic hepatic tissues. Results: The expression of MDR1, MRP1 and BCRP mRNA (messenger ribonucleic acid) was 1.15±0.24, 0.64±0.33, and 1.07±0.32 in hepatocellular carcinoma and 0.36±0.14, 0.19±0.06, and 0.31±0.09 in paraneoplastic hepatic tissues. The expression of MDR1, MRP1 and BCRP mRNA was 1.38±0.26, 0.73±0.35, and 1.34±0.21 in poorly differentiated hepatocellular carcinoma and 0.74±0.32, 0.30±0.11, and 0.45±0.13 in well differentiated hepatic tissues. The immunohistochemical positive substance was detected in the plasma membrane and cytoplasm. The positive rates of P-gp, MRP1 and BCRP were 82.35%, 58.82%, and 79.41% in hepatocellular carcinoma and 42.11%, 26.32%, and 36.84% in paraneoplastic hepatic tissues, respectively. The positive rates of P-gp, MRP1 and BCRP were 100.00%, 81.25%, and 100.00% in poorly differentiated hepatocellular carcinoma and 66.67%, 38.89%, and 61.11% in well differentiated hepatic tissues. The expression of three indicies in hepatocellular carcinoma was higher than that in paraneoplastic hepatic tissues (P<0.05). The expression of P-gp/MDR1, MRP1 and BCRP in poorly differentiated hepatocellular carcinoma was higher than that in well differentiated hepatic tissues (P<0.05). No correlation was found among the three indices. Conclusion: Intrinsic multidrug resistance exsists in hepatocellular carcinoma, with various mechanisms. The multidrug resistance of HCC (hepatic cell carcinoma) is related to P-gp/MDR1, MRP1 and BCRP. MRP1 and BCRP may be targets for reversing multidrug resistance.
ABSTRACT
Objective To explore the possibility that rat bone mesenchymal cells (BMSCs) can differentiate into hepatocytes under the affection of fetal liver filtrate. Methods PAS and green indigo dye were used to detect glycogen and differential level of hepatocytes, respectively. The concentration of ALT, AST, ALP in the culture supernatant were served as markers of hepaocyte function. Results Fourteen days after induced by the fetal liver filtrate, BMSCs changed their shapes into polygon, oval or round. Some of BMSCs were positive for AFP and ALB at 7 days after induction, then the number of positive cells increased, and most of BMSCs expressed AFP and ALB till 21days. The PAS reaction and indocyanine green(ICG) intaking also appeared at 7days. Enzyme in supernatant such as ALT, AST, ALP were fristly detected at 7days and peaked at 14days,then the level declined. Conclusion The fetal rat liver filtrate was able to induce BMSCs into cells with function and characteristics of hepatocytes.
ABSTRACT
BACKGROUND: Studies of biological characteristics of mesenchymal stem cells (MSCs) and regulatory factors that influenced the differentiation of MSCs have shown that the proportion of the natural differentiation from in vitro primarily cultured MSCs into hepatocytes was low, and to select a suitable inductor is important to enhance the differentiation of MSCs into hepatocytes.OBJECTIVE: To verify the feasibility of induced differentiation of rat bone marrow MSCs (BMSCs) into hepatocytes using the combination of hepatocyte growth factor (HGF), epidermal growth factor (EGF) and fibroblast growth factor (FGF-4).DESIGN, TIME AND SETTING: The cytological in vitro study was performed at the Experimental Center, Weifang Medical College in August 2007.MATERIALS: Totally 40 Sprague-Dawley rats were supplied by the Experimental Animal Center, Weifang Medical College.METHODS: Rat BMSCs were incubated by adherent method. BMSCs at passage 3 were assigned to 2 groups. BMSCs in the blank control group were treated with L-DMEM containing 10% fetal bovine serum. BMSCs in the combination group were treated with 10 μg/L FGF, 8 μg/L HGF and 8 μg/L EGF following above-mentioned procedures.MAIN OUTCOME MEASURES: Inverted microscope was used to observe the morphological changes in cells.Immunofluorescence method was used to observe the expression of alpha-fetoprotein (AFP) and albumin (ALB). PAS was employed to detect the expression of glycogen. Fox green intake experiment was conducted. Enzymology was utilized to test the contents of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP).RESULTS: BMSCs in the combination group presented polygonal, orbicular or round shape. BMSCs in the blank control group remained spindle. BMSCs in the combination group were positive for AFP and ALB at day 14 following culture, and a few PAS-positive and fox green-positive cells were found at day 7. Positive cells became more over time. Synthesis of ALT, AST and ALP was detected at day 14, reached a peak at 21 days, and then decreased. Above-described indexes were negative in the blank control group.CONCLUSION: After induced by the FGF, HGF and EGF, BMSCs have the ability to differentiate into hepatocytes in vitro.
ABSTRACT
BACKGROUND: There are few studies conceming morphological charactedstics, space-time distribution and differentiation of hepatic stem cells during embryo liver development.OBJECTIVE: To understand the action of alpha fetoprotein, cytokeratin-19 (CK19) and c-Met in the liver through observing the expression of them.DESIGN, TIME AND SETTING: The in vitro cytological observational study was performed at the Central Laboratory of Weifang Medical College from June 2005 to December 2006.MATERIALS: A total of 40 embryo samples were obtained from 3-rnonth aborted fetus, which were supplied by Hospital Affiliated to Weifang Medical College.METHODS: Aborted embryo was collected and made into sections within 30 minutes. Fetal age was defined according to embryonic layer formation, somite number and organ development under a microscope. Sample sections with fetal age of 3-12weeks were selected. One was collected from every eleven sections and underwent immunohistochemical staining.MAIN OUTCOME MEASURES: Expression of alpha fetoprotein, CK19 and c-Met was measured in embryo hepatic stem cells aged 3-12 weeks.RESULTS: At 3-5 weeks, samples were positive for alpha fetoprotein and c-Met, which were indicated as hepatic stem ceils. At 10-12 weeks, alpha fetoprotein- and c-Met-positive cells were mainly distributed surrounding the header, which suggested that hepatic stem cells were mainly located at hepatic cord of the header. This had similar distribution as adult hepatic oval cells (adult hepatic stem cells). CK19-positive reaction was found at week 7, and mainly at hepatic cord cells, bile duct sheet cells and bile duct epithelial cells at 10-11 weeks. CKlg-positive reaction was only seen at the bile duct sheet and bile duct epithelial cells at week 12. At this time, all bile duct sheet cells and bile duct epithelial cells were positive for alpha fetoprotein, c-Met and CK19.CONCLUSION: CK19-positive reaction was not found in hepatic stem cells, but only detected in bile duct epithelial cells and progenitor calls. CK19 may be not fit for a marker of hepatic stem cells. All bile duct sheet and bile duct epithelial cells are positive for alpha fetoprotein, c-Met and CK19. It is assumed that alpha fetoprotein+/c-Met+/CK19+ may be bile duct progenitor calls.
ABSTRACT
BACKGROUND: Vascular endothelial growth factor family and its receptor play an important role in the process of angiogenesis and neovascularization. Recently, the effect of vascular endothelial growth factor family on blood has been paid much attention. OBJECTIVE: To observe the expression of vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor C (VEGFC) and their receptors as well as angiopoietin-1 (ang-1),angiopoietin-2(ang-2) and their receptors in the blood island of yolk sac and aorta-gonadalmesonephros (AGM) region at embryonic 3 to 12 weeks, so as to investigate the effect of VEGF and angiopoietin family in the process of haematogenesis. DESIGN: Single sample observation. SETTING: Weifang Medical College, Experimental Center of Morphology and Staff Room of Anatomy. MATERIALS: This experiment was carried out at Weifang Medical College from February 2002 to August 2004. Specimens were collected from 47 pregnant women's 3-to-12-week abortive embryos. Informed consent was obtained from the pregnant women. METHODS: Specimens were performed successive sections. Two sections were drawn out every other 10 sections. Hematoxylin-eosin staining and immunohistochemical staining were performed. Polyclonal anti-vascular endothelial growth factor C, fms like protein tyrosine kinase(PTK), flt-4,ang-1, ang-2,Tie-2 antibody, monoclonal anti-vascular endothelial growth factor A and fetal liver kinase 1 (flk1) antibody were used for incubation overnight at 4 ℃ .Goat anti-mouse IgG and SABC solution were used separately for 2 hours. 3,3'2 diaminoazobenzidine (DAB) was used to develop. Serum of normal rabbit or mouse were used separately to replace primary antibody as negative control. They were observed and taken photographs under optical microscope. MAIN OUTCOME MEASURES: ①Blank expression of VEGFA and VEGFC and their receptors in the blood island of yolk sac and AGM region at embryonic 3 to 12 weeks. ②Blank expression of ang-1 and ang-2 and their receptors in the blood island of yolk sac and AGM region at embryonic 3 to 12 weeks. RESULTS: ①On the 21st to 25th day , vascular endothelial cells and hematopoietic cells in blood island of yolk sac strongly expressed VEGFA and its receptor fms like PTK and flk1, VEGFC and its receptor flk4, ang2 and its receptor Tie-2 protein, weakly expressed ang-1 protein. ②From the fourth week of development, dorsal aorta and mesonephros expressed above-mentioned various factors and their receptors . Immune positive reactants gathered in the large and round hematopoietic cells with nucleus. The cell quantity reached the peak at week 7. After week 8, the number of positive cells was significantly decreased, and almost all the blood cells were immune negative reaction at week 12. ③Gonad mainly expressed VEGFA , fms like PTK, flt-4,ang-1 ,ang-2 and Tie-2 protein at weeks 6 to 8 , but did not express VEGFC and flkl. ④ The expression of above-mentioned factors were not detected in the vascular endothelial cells in AGM region. CONCLUSION: Hematopoietic cells and endothelial cells of blood island of yolk sac of human embryo as well as dorsal aorta and mesonephros coexpresses various factors related to angiogenesis and haematogenesis. Haematogenesis of human embryos occurs at the fourth week.
ABSTRACT
BACKGROUND: There is an intimate temporal and spatial relationship between growth of primitive cardiac cells, septum transversum mesenchyme and liver development. The signal from primitive cardiac cells and septum transversum mesenchyme induces the ventral foregut endoderm cells specialize toward hepatocytes. While the septum transversum mesenchyme provides a suitable environment for forming the liver bud and promoting the growth and differentiation. However, the molecular mechanism of this induction is not yet delineated.OBJECTIVE: Using alpha-fetal protein (AFP), c-Met and cytokeratin (CK) 19 as markers of hepatic stem cells, the growth of early human embryo of 3-5 weeks and morphologic characteristic of hepatic stem cells were observed to demonstrate the characteristic and factors that affected the proliferation and differentiation of hepatic stem cell, which provided experimental evidence for basic research and clinical application of hepatic stem cells.DESIGN: An opening experiment was designed.SETTING: Department of Anatomy, Weifang Medical College.MATERIALS: The experiment was carried out at the Scientific Research Center of Chengdu Medical College between September 2004 and January 2005. Twenty cases fresh human embryos aged less than 2 months were collected with signed agreements of the pregnant women suffering from pregnancy termination with mifepristone. The samples were fixed with 40 g/L polymerisatum in 20 minutes and embedded routinely in paraffin, and then 5 μm thick series sections were continuously made. After hematoxylin-eosin staining, the embryonicage was determined under the microscope according to the length of embryos, the number of somites and the development of organs, which was referring to the Jirasek's staging standard of human embryo.METHODS: The immunohistochemical staining was conducted with SABC method on one of every ten sections, which were incubated overnight at 4 ℃ with polyclonal antibodies against hepatocyte growth factor (HGF),c-Met, insulin-like growth factor (IGF-Ⅰ), IGF-Ⅰ receptor (IGF-IR), transforming growth factor (TGFβ1), TGFβR1, TGFβR2 or monoclonal antibodies against proliferating cell nuclear antigen (PCNA), AFP and CK19.The following day, the sections were incubated for 2 hours at room temperature with biotinylated anti-mouse or anti-rabbit IgG and SABC liquid respectively, and then diaminobenzidine (DAB) was used to color them. The negative control was conducted with the phosphate buffer, then the sections were observed and photographed under light microscope.MAIN OUTCOME MEASUERS: ①the morphologic characteristic of human hepatic stem cells and immunohistochemical staining of markers②the expression of HGF, IGF-Ⅰ, TGFβ1 and their receptors on human embryonic livers of 3-5 weeks, primitive cardiac cells and septum transversum mesenchyme.RESULTS: ①The morphologic characteristic of human hepatic stem cells and immunohistochemical staining of markers: The hepatic bud formed at the end of 3rd week and migrated into the septum transversum mesenchyme to form the hepatic cords at the 4th week. The cells structuring the hepatic cords displayed the typical characteristic of immature cells. At the 5th week, the number of cells within the hepatic cords, the size of cell body,the cytoplasmic acidophilia all increased, whereas the basophilia of nuclei decreased. However the cellular forms were still homogeneous and displayed the typical characteristic of immature cells. The cells of hepatic cords were negative for PCNA response during 3rd-4th week but began to express positive at the 5th week, mainly in the nucleus and minority cellular cytoplasm showed weak positive. Most hepatic cells during 3rd-5th weeks were positive for AFP, c-Met and negative for CK19. The immunologic reaction depositors of AFP positive cells were located in the nuclei, cytoplasm and membrane of the hepatocytes, and c-Met presented mainly in the nuclei and the positive signal was weak in the cytoplasm. ②Expressions of HGF, IGF-Ⅰ, TGFβ1 and their receptors in the embryonic human liver, primitive heart and septum transversum mesenchyme: At the 4th week,the c-Met expressed only in all hepatocytes, whereas the other growth factors and their receptors were undetectable. At the 5th week, all the growth factors, except HGF, were expressed in the hepatocytes. The immunologic reaction depositors of TGFβ1, TGFβ1R1 and TGFβ1R2 were located in the cytoplasm and cell membrane. The positive response of IGF-Ⅰ and IGF-IR were present at nuclei, cytoplasm and cell membrane. At the 3rd-5th week, myocardial cells surrounding liver bud or hepatic cord and the septum transversum mesenchyme were positive for HGF, TGFβ1 and IGF-Ⅰ,with the signals were aggregated mainly in cytoplasm and minority nucei.CONCLUSION: ①It was at the end of 3rd week that part of endoderm cells in foregut ventral were specialized to hepatic stem cells. ②The undifferentiated hepatic stem cells could be drawn to develop to the liver stem cells with bi-directional differentiation potentials by using specific markers for studying human embryonic liver stem cells. According to the corresponding relation of embryonic age between human and rats, the time studying the rat hepatic stem cells could be calculated. ③HGF, IGF-Ⅰ,TGFβ1 and their receptors promoted the early development of human embryonic liver.