Objective
To investigate the mechanism of AMP-activated protein kinase (AMPK) in hepatic ischemia-reperfusion injury (HIRI).
Methods
① Grouping. Forty-two mice were randomly divided into Sham group, 4 ischemia reperfusion (IR) group of different times (2, 6, 12, and 24 h), Compound C group, and Compound C+repamycin (Rapa) group, each group enrolled in 6 mice. Compound C group: mice were modeled at 1 h after intraperitoneal injection of Compound C (25 mg/kg). Compound C+Rapa group: mice were modeled at 1 h after intraperitoneal injection of rapamycin (1 mg/kg) and Compound C (25 mg/kg). Mice of 4 IR groups, Compound C group, and Compound C+Rapa group were used to prepare HIRI model. Mice of Sham group were treated only for laparotomy, freeing the first portal hepatis and closing peritoneal. ② To filter the best IR time. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum of mice in Sham group and IR groups of 4 different reperfusion time points were measured. The pathological changes of liver tissues were observed by HE staining, and the expressions of related proteins in liver tissue of mice were detected by Western blot. Considering the results of blood biochemical test, HE staining, and Western blot together to determine the best IR point. ③ The exploration of signal pathway for AMPK. The expressions of proliferating cell nuclear antigen (PCNA) were observed by immunohistochemical staining in the liver tissues of IR-12 h group, Compound C group (12 h after IR) and compound C+Rapa group (12 h after IR). The mitochondrial damage was observed by rhodamine 123 staining, and the apoptotic status of liver cells was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay (TUNEL).
Results
① The 12 h after IR was the best observation time point. Compared with IR-12 h group, the levels of ALT and AST in Sham group, IR-2, 6, and 24 h groups were lower (P<0.05). HE staining showed that liver tissue destruction in IR-12 h group was the most severe. Western blot showed that, expressions of AMPKα, phosphorylated adenylate activated protein kinase α (p-AMPKα), Nip3-like protein X (Nix), BCL-2 homologous water-soluble protein (Bax), as well as ratio of autophagy microtubule-associated protein light chain 3 (LC3)Ⅱto LC3Ⅰof Sham group, IR-2, 6, and 24 h group were all lower than those of IR-12 h group (P<0.05), but the expressions of phosphorylated mammalian target of Rapa (p-mTOR) of Sham group, IR-2, 6, and 24 h group were all higher (P<0.05). Therefore, 12 h after IR was the best time to observe. ② Compared with IR-12 h group, the expression level of PCNA protein in liver tissue of Compound C group was lower (P<0.05), the mitochondrial luminescence intensity was weaker and the apoptotic cells were more. Compared with Compound C group, the expression of PCNA protein in the liver tissue of the Compound C+Rapa group was higher (P<0.05), the mitochondrial intensity was stronger and the apoptotic cells were less. ③ Compared with IR-12 h group, the expressions of Nix and p-AMPKα, and ratio of LC3Ⅱ to LC3Ⅰ in liver tissue of Compound C group decreased (P<0.05), while the expressions of p-mTOR, Caspase-3, and Cleaved Caspase-3 increased (P<0.05). Compared with Compound C group, the expressions of p-AMPKα and Nix in the liver tissue of Compound C+Rapa group increased (P<0.05), while the expressions of p-mTOR, Caspase-3, and Cleaved Caspase-3 decreased (P<0.05).
Conclusion
During the HIRI in mouse, AMPK regulates mitophagy and apoptosis through the mTOR/Nix pathway.
Objective To investigate the changes in osteoprotegerin (OPG) / receptor activator of nuclear factor-κB ligand (RANKL) ratio in sepsis-associated acute lung injury (SA-ALI) and the role of regulation of this ratio on the inflammatory response in SA-ALI. Methods Eighteen C57BL/6 male mice were randomly divided into sham operation group, cecal ligation and perforation (CLP) group and RANKL group, with 6 mice in each group. Before the experiment, the RANKL group was intraperitoneally injected with 5 μg (0.2 mL) of recombinant RANKL antibody, whereas both the sham operation group and the CLP group were intraperitoneally injected with a volume-matched normal saline. One hour later, the sham operation group underwent only abdominal exploration and repositioning, while the other groups underwent the CLP surgery to induce the SA-ALI model. After 24 h of modelling, all mice were sacrificed and samples were collected. Pathological evaluation of lung tissues was performed by haematoxylin-eosin staining; enzyme-linked immunosorbent assay was used to detect serum concentrations of interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β; while the mRNA and protein expression of OPG and RANKL, along with their ratio values, were detected by real-time polymerase chain reaction for quantitative analysis and protein immunoblotting. Results The SA-ALI mouse model was successfully established. Compared with the sham operation group, mice in the CLP group showed disturbed alveolar structure, obvious alveolar and interstitial haemorrhage and inflammatory cell infiltration, elevated serum levels of IL-6, TNF-α and IL-1β (P<0.05), significantly increased mRNA and protein expression of OPG and elevated OPG/RANKL ratio in lung tissue (P<0.05), whereas RANKL mRNA and protein expression was significantly decreased (P<0.05). Compared with the CLP group, the pathological damage of lung tissue in the RANKL group was reduced, the infiltration of alveolar and interstitial inflammatory cells was significantly improved, and the alveolar structure and morphology were more regular, with lower serum levels of IL-6, TNF-α and IL-1β (P<0.05), significantly lower mRNA and protein expression of OPG and OPG/RANKL ratio in lung tissue (P<0.05), and significantly higher mRNA and protein expression of RANKL in lung tissue (P<0.05). Conclusion The alteration of OPG/RANKL ratio may be related to the pathophysiological process of SA-ALI, and the decrease in its level may reflect the attenuation of the inflammatory response in SA-ALI.
Objective To study the culture and purification of the fetal mouse liver mesenchymal stem cells(MSCs) in vitro and to investigate their differentiation potential and the composite ability with true bone ceramic(TBC). Methods The single cell suspension of MSCs was primarily cultured and passaged, which was prepared from the fetal mouse liver; the flow cytometry was applied to detectCD29, CD34, CD44 and CD45. The osteogenic differentiation was induced in chemical inducing system; the osteogenic induction potency was tested. The purified fetal mouse liver MSCs were compounded with TBC covered with collagen type Ⅰ in vitro and the cell attachment and proliferation to the TBC were observed. Results The primary MSCs of fetal mouse liver were easy to culture in vitro. They proliferated well and were easy to subcultured. The proliferation ability of primary and passaged MSCs was similar. Flow cytometric analysis showed the positive results for CD29, CD44 and the negative results for CD34, CD45. After 7 days of induction, the MSCs expressed collagen type I and alkaline phosphatase(ALP) highly. After 14 days of induction, the fixed quantity of ALP increased significantly. After 28 days of induction, calcium accumulation was observed by Von Kossa’s staining. Many liver MSCs attached to the surface of TBC. Conclusion The MSCs of the fetalmouse liver can be obtained, subcultured and purified easily. After culturing in chemical inducing system, the MSCs of fetal mouse liver can be successfully induced to osteoblast-like cells, attach to the surface of TBC and proliferate well.
Weightlessness in the space environment affects astronauts’ learning memory and cognitive function. Repetitive transcranial magnetic stimulation has been shown to be effective in improving cognitive dysfunction. In this study, we investigated the effects of repetitive transcranial magnetic stimulation on neural excitability and ion channels in simulated weightlessness mice from a neurophysiological perspective. Young C57 mice were divided into control, hindlimb unloading and magnetic stimulation groups. The mice in the hindlimb unloading and magnetic stimulation groups were treated with hindlimb unloading for 14 days to establish a simulated weightlessness model, while the mice in the magnetic stimulation group were subjected to 14 days of repetitive transcranial magnetic stimulation. Using isolated brain slice patch clamp experiments, the relevant indexes of action potential and the kinetic property changes of voltage-gated sodium and potassium channels were detected to analyze the excitability of neurons and their ion channel mechanisms. The results showed that the behavioral cognitive ability and neuronal excitability of the mice decreased significantly with hindlimb unloading. Repetitive transcranial magnetic stimulation could significantly improve the cognitive impairment and neuroelectrophysiological indexes of the hindlimb unloading mice. Repetitive transcranial magnetic stimulation may change the activation, inactivation and reactivation process of sodium and potassium ion channels by promoting sodium ion outflow and inhibiting potassium ion, and affect the dynamic characteristics of ion channels, so as to enhance the excitability of single neurons and improve the cognitive damage and spatial memory ability of hindlimb unloading mice.
摘要:目的:探討表達吲哚胺2,3二氧化酶(IDO)的KC對同種異體小鼠移植皮片存活時間的影響及其機制。方法:構建BABL/c →C57BL/6的皮膚移植模型,分別于移植術后第2、7、14天輸注KC,于移植術后第7天每組各取2只皮瓣行HE染色和TUNEL以檢測淋巴細胞浸潤和凋亡情況。KaplanMeier對數秩檢驗對各組進行生存分析。結果:輸入表達IDO和FasL的KC能明顯延長BABL/c →C57BL/6皮膚移植模型中皮膚移植物的存活時間,1－甲基色氨酸能阻斷此效應。IFNγ組皮瓣浸潤淋巴細胞的凋亡率較高(Plt;0.05)。結論:表達IDO和FasL的KC在體內能明顯延長同種異體小鼠皮片的存活時間,IDO在KC維持外周免疫耐受中發揮重要作用。Abstract: Objective: To investigate kupffer cells(KC) expressing indoleamine 2,3dioxygenase(IDO) on the survival of grafted skin in mouse and its underlying mechanism. Methods: BABL/c skin was transplanted to C57BL/6. Donor KC were injected i.v. at days 2,7, 14 before transplantation. HE and TUNELAP were used to identify infiltrating cells and apoptotic cells in section of skin allografts from 7 days posttransplantation respectively. The survival rate of recipients among groups were analyzed by Logrank test. Results: Injection of KC expressing IDO and FasL from BABL/c mice into C57BL/6 could prolong a skin graft survival from the donor, but 1methyltryptophan could block the effect in vivo. The apoptosis rate of lymphocyte among skin graft in IFNγ group is more than other group(Plt;0.05). Conclusion: IDO and FasLexpressing KC from the donor of mouse can significantly prolong the skin graft survival. IDO may play an important role in KC to induce immune tolerance.
ObjectiveTo investigate the mechanism of muscle-derived cells (MDCs) in repairing sciatic nerve defects in mice by observing the early growth of damaged peripheral nerves.MethodsThe hind limb skeletal muscles of mice carrying enhanced green fluorescent protein (EGFP) was collected to extract and culture EGFP-MDCs to P1 generation for later experiments. Five-mm-long nerve defects were created in the right sciatic nerves of C57BL/6 mice to establish a peripheral nerve defect model. The two stumps of sciatic nerve were bridged with 7-mm-long polyurethane (PUR) conduit. For the MDC group, EGFP-MDCs were injected into the PUR conduit. The PUR group without EGFP-MDCs was used as the negative control group. At 1 and 2 weeks after operation, the proximal and distal nerve stumps of the surgical side were collected to generally observe the early growth of nerve. Immunofluorescence staining of S100β, the marker of Schwann cells, was performed on longitudinal frozen sections of nerve tissues to calculate the maximum migration distance of Schwann cells, and observe the source of the Schwann cells expressing S100β. Immunofluorescence staining of phosphorylated erb-b2 receptor tyrosine kinase 2 (p-ErbB2) and phosphorylated focal adhesion kinase (p-FAK) in transverse frozen sections of nerve tissue was performed to calculate the positive rates of both proteins.ResultsThe general observation showed that the proximal and distal stumps of the surgical side in PUR group were not connected at 1 and 2 weeks after operation, while the bilateral nerve stumps in the MDC group were connected at 2 weeks after operation. Immunofluorescence staining showed that the Schwann cells expressing S100β in proximal and distal nerve stumps of PUR group and MDC group was not connected at 1 week after operation. At 2 weeks after operation, the Schwann cells expressing S100β in the two nerve stumps of the MDC group were connected, but not in the PUR group. At 2 weeks after operation, the sum of the maximum migration distance of Schwann cells in the regenerated nerve in both two groups was significantly increased when compared with that in each group at 1 week after operation, and that of MDC group was significantly higher than that in the PUR group at both 1 and 2 weeks after operation, the differences were all significant (P<0.05). At 1 week after operation, the positive rates of p-ErbB2 and p-FAK in the proximal nerve stump of MDC group were significantly higher than those in PUR group (P<0.05). There was no significant difference in the positive rate of p-ErbB2 of proximal stump between the two groups at 2 weeks after operation (t=0.327, P=0.747), while the positive rate of p-FAK of MDC group was significantly higher than that of PUR group (t=4.470, P=0.000). At 1 and 2 weeks after operation, the positive rates of p-ErbB2 and p-FAK in the distal stump of MDC group were significantly higher than those in PUR group (P<0.05). At 1 and 2 weeks after operation, part of Schwann cells expressing S100β, which were derived from EGFP-MDCs, could be observed in the regenerated nerves of MDC group.ConclusionMDCs can promote the phosphorylation of ErbB2 and FAK in the nerve stumps of mice, and promote the migration of Schwann cells. MDCs can be differentiated into cells expressing the Schwann cell marker S100β, or as other cellular components, to involve in the early repair of peripheral nerves.
Objective
To explore heterotopic chondrogenesis of canine myoblasts induced by cartilage-derived morphogenetic protein 2 (CDMP-2) and transforming growth factor β1 (TGF-β1) which were seeded on poly (lactide-co-glycolide) (PLGA) scaffolds after implantation in a subcutaneous pocket of nude mice.
Methods
Myoblasts from rectus femoris of 1-year-old Beagle were seeded on PLGA scaffolds and cultured in medium containing CDMP-2 and TGF-β1 for 2 weeks in vitro. Then induced myoblasts-PLGA scaffold, uninduced myoblasts-PLGA scaffold, CDMP-2 and TGF-β1-PLGA scaffold, and simple PLGA scaffold were implanted into 4 zygomorphic back subcutaneous pockets of 24 nude mice in groups A, B, C, and D, respectively. At 8 and 12 weeks, the samples were harvested for general observation, HE staining and toluidine blue staining, immunohistochemical staining for collagen type I and collagen type II; the mRNA expressions of collagen type I, collagen type II, Aggrecan, and Sox9 were determined by RT-PCR, the glycosaminoglycans (GAG) content by Alician blue staining, and the compressive elastic modulus by biomechanics.
Results
In group A, cartilaginoid tissue was milky white with smooth surface and slight elasticity at 8 weeks, and had similar appearance and elasticity to normal cartilage tissue at 12 weeks. In group B, few residual tissue remained at 8 weeks, and was completely degraded at 12 weeks. In groups C and D, the implants disappeared at 8 weeks. HE staining showed that mature cartilage lacuna formed of group A at 8 and 12 weeks; no cartilage lacuna formed in group B at 8 weeks. Toluidine blue staining confirmed that new cartilage cells were oval and arranged in line, with lacuna and blue-staining positive cytoplasm and extracellular matrix in group A at 8 and 12 weeks; no blue metachromatic extracellular matrix was seen in group B at 8 weeks. Collagen type I and collagen type II expressed positively in group A, did not expressed in group B by immunohistochemical staining. At 8 weeks, the mRNA expressions of collagen type I, collagen type II, Aggrecan, and Sox9 were detected by RT-PCR in group A at 8 and 12 weeks, but negative results were shown in group B. The compressive elastic modulus and GAG content of group A were (90.79 ± 1.78) MPa and (10.20 ± 1.07) μg/mL respectively at 12 weeks, showing significant differences when compared with normal meniscus (P lt; 0.05).
Conclusion
Induced myoblasts-PLGA scaffolds can stably express chondrogenic phenotype in a heterotopic model of cartilage transplantation and represent a suitable tool for tissue engineering of menisci.
In the development of radio frequency (RF) coils for better quality of the mini-type permanent magnetic resonance imager for using in the small animal imaging, the solenoid RF coil has a special advantage for permanent magnetic system based on analyses of various types of RF coils. However, it is not satisfied for imaging if the RF coils are directly used. By theoretical analyses of the magnetic field properties produced from the solenoid coil, the research direction was determined by careful studies to raise further the uniformity of the magnetic field coil, receiving coil sensitivity for signals and signal-to-noise ratio (SNR). The method had certain advantages and avoided some shortcomings of the other different coil types, such as, birdcage coil, saddle shaped coil and phased array coil by using the alloy materials (from our own patent). The RF coils were designed, developed and made for keeled applicable to permanent magnet-type magnetic resonance imager, multi-coil combination-type, single-channel overall RF receiving coil, and applied for a patent. Mounted on three instruments (25 mm aperture, with main magnetic field strength of 0.5 T or 1.5 T, and 50 mm aperture, with main magnetic field strength of 0.48 T), we performed experiments with mice, rats, and nude mice bearing tumors. The experimental results indicated that the RF receiving coil was fully applicable to the permanent magnet-type imaging system.
The model of transplanted colonic SW480 cell line carcinoma in gymnomouse body was set up to observe the effect of octapeptide somatostatin (SMS 201-995,SMS) on the transplanted carcinoma and elucidate its mechanism. Results: the volume, weight, DNA and protein content in carcinoma cell, cell amount and proliferation index of S and G2M phase in SMS group and SMS+PG (pentagastrin) group were markedly lower than those in PG group and control group, those of PG group were markedly higher than those in control group.The cell amount of G0/G1 phase in SMS group and SMS+PG group was markedly higher than that in PG group and control group, and that of PG group was markedly lower than that in control group.All these suggested that somatostatin could not only inhibit the growth of transplanted human colonic SW480 cell line carcinoma directly but also inhibit the growthpromoting effect of gastrin on the transplanted carcinoma.The mechanism might be that somatostatin inhibit the synthesis of cAMP, DNA and protein in carcinoma cells, then inhibit the cell growing from G0/G1 phase to S and G2M phases.Our study might provide experimental basis for the homonotherapy with analogue of somatostatin in patients with large intestine carcinoma.
Objective To study the effects of morroniside (MOR) on the proliferation and osteogenic differentiation of mouse MC3T3-E1 cells. MethodsThe 4th generation MC3T3-E1 cells were randomly divided into 6 groups: control group (group A), MOR low dose group (10 μmol/L, group B), MOR medium-low dose group (20 μmol/L, group C), MOR medium dose group (40 μmol/L, group D), MOR medium-high dose group (80 μmol/L, group E), and MOR high dose group (100 μmol/L, group F). The proliferation activity of each group was detected by cell counting kit 8 (CCK-8) assay; the bone differentiation and mineralized nodule formation of each group were detected by alizarin red staining; real-time fluorescence quantitative PCR (RT-qPCR) was performed to detect cyclin-dependent kinase inhibitor 1A (P21), recombinant Cyclin D1 (CCND1), proliferating cell nuclear antigen (PCNA), alkaline phosphatase (ALP), collagen type Ⅰ (COL-1), bone morphogenetic protein 2 (BMP-2), and adenosine A2A receptor (A2AR) mRNA expressions; Western blot was used to detecte the expressions of osteopontin (OPN), Runt-related transcription factor 2 (RUNX2), and adenosine A2AR protein. ResultsThe CCK-8 assay showed that the absorbance (A) values of groups B to F were significantly higher than that of group A at 24 hours of culture, with group C significantly higher than the rest of the groups (P<0.05). The MOR concentration (20 μmol/L) of group C was selected for the subsequent CCK-8 assay; the results showed that the A values of group C were significantly higher than those of group A at 24, 48, and 72 hours of culture (P<0.05). Alizarin red staining showed that orange-red mineralized nodules were visible in all groups and the number of mineralized nodules was significantly higher in groups B and C than in group A (P<0.05). RT-qPCR showed that the relative expressions of P21, CCND1, and PCNA mRNAs were significantly higher in group C than in group A (P<0.05). The expressions of ALP, BMP-2, COL-1, and adenosine A2AR mRNAs in groups B to E were significantly higher than those in group A, with the expressions of ALP, BMP-2, COL-1 mRNAs in group C significantly higher than the rest of the groups (P<0.05). Compared with group A, the expressions of OPN and RUNX2 proteins in groups B and C were significantly increased, while those in group D and E were significantly inhibited (P<0.05). There was no significant difference between groups B and C and between groups D and E (P>0.05). The relative expression of adenosine A2AR protein in groups B to E was significantly higher than that in group A, with group C significantly higher than the rest of the groups (P<0.05). Conclusion MOR can promote the proliferation and osteogenic differentiation of MC3T3-E1 cells; the mechanism of MOR may be achieved by interacting with adenosine A2AR.
