ObjectiveTo investigate the osteogenic differentiation potential and the biological features of synovium-derived mesenchymal stem cells (SMSCs) in vitro and to observe the osteogenic capability of the composite scaffolds constructed with SMSCs and hydroxylapatite/chitosan/poly L-latic acid (HA/CS/PLLA) in vivo. MethodSMSCs were separated and cultured with adherent method and enzymatic digestion method. Specific phenotypes of SMSCs were detected by flow cytometry after purification. Then, SMSCs were identified by oil red O staining, alkaline phosphatase (ALP) staining, and alizarin red staining after adipogenic and osteogenic induction, respectively. In vitro experiments:the expressions of osteogenic related genes[osteocalcin (OCN), collagen type I, ALP, and Runx-2] were detected by real-time fluorescent quantitative PCR at 1, 7, 14, 21, and 28 days after osteogenic induction; ALP activities were also determined by ELISA at 1, 3, 5, 7, 9, and 11 days after osteogenic induction; meanwhile, extracellular matrix calcium mineralization was detected by alizarin red S method at 7, 14, 21, and 28 days after osteogenic induction; the normal SMSCs were harvested as control group. In vivo experiments:Twenty-four Sprague Dawley (SD) rats were randomly divided into experimental group (n=12) and control group (n=12) . The 3rd passage SMSCs were seeded on HA/CS/PLLA to construct composite scaffolds, after adhesion for 72 hours in vitro, the composite scaffolds were implanted into the right thigh muscle of 12 SD rats as experimental group; HA/CS/PLLA was implanted into the right thigh muscle of the other 12 SD rats as control group. At 4 and 8 weeks after implantation, the scaffolds were harvested for X-ray film and histological examination to observe ectopic bone formation. ResultsThe positive rates of CD147, CD90, CD105, and CD44 were more than 95%, while the positive rates of CD117, CD34, CD14, and CD45 were less than 10%. Oil red O staining demonstrated red lipid droplets in the cytoplasm, and alizarin red staining showed flaky red calcifications, and cytoplasm was dyed brown by the ALP staining. The mRNA expressions of collagen type I, ALP, and Runx-2 were significantly increased at 7 days after osteogenic induction, and OCN mRNA expression was significantly increased at 14 days after osteogenic induction; ALP activity was significantly higher at 5, 7, 9, 11 days after osteogenic induction in the SMSC-induced group than control group and reached a maximum at 7 days (P<0.05) . Calcium mineralization was significantly enhanced at 14 days after osteogenic induction, and gradually increased with time (P<0.05) ; moreover, it was significantly higher in the SMSC-induced group than control group (P<0.05) . X-ray and histological examination demonstrated that the new bone tissues formed in 2 groups, but bone formation content of the experimental group was significantly more than that of the control group at 4 and 8 weeks after implantation (P<0.05) . ConclusionsSMSCs can be induced into osteoblasts both in vitro and in vivo, so SMSCs might be a promising seed cells for bone tissue engineering.
ObjectiveTo evaluate the effect of time-related administration of methotrexate (MTX) on neural cell apoptosis in rats after spinal cord injury (SCI) so as to investigate its potential neuroprotective mechanism and appropriate administration time. MethodA total of 120 male Sprague Dawley rats, 247-286 g in weight, were randomly divided into 4 groups (n=30) :sham group (group A), control group (group B), MTX treating group (group C), and MTX prophylaxis group (group D). The SCI model was established in the rats of groups B, C, and D by improved Allen method, and just laminectomy was performed in group A. MTX (0.5 mg/kg) was administered with tail vein injection at 1, 6, 12, 18, and 24 hours after injury in group C, and at 30 minutes before injury and at 6, 12, 18, and 24 hours after injury in group D; the equivalence saline was injected at 1, 6, 12, 18, and 24 hours after injury in groups A and B. Basso-Beattie-Bresnahan (BBB) score was used to evaluate the neural function at 1, 3, 7, 14, and 21 days after injury, HE staining to observe histological changes, immunohistochemical staining and TUNEL method to measure the expression of Caspase-3 and neural cells apoptosis, respectively. ResultsTen rats died during the experiment in groups B, C, and D; 25 rats in each group were included into the experiments at last. BBB score of group A was significantly higher than that of groups B, C, and D at all time points after injury (P<0.05) . BBB score of groups C and D were significantly higher than that of group B at 3, 7, 14, and 21 days (P<0.05) , and BBB score of group D was significantly higher than that of group C at 3, 7, and 14 days (P<0.05) . The histological observation showed normal structure of spinal cord at all time points after injury in group A. While the degree of SCI in group D was lighter than that in groups B and C, and group C was lighter than group B. At 14 days after injury, the degree of SCI in groups B, C, and D tend to keep the same. The number of Caspase-3 and TUNEL positive cells of groups B, C, and D was significantly more than that of group A at all time points after injury (P<0.05) , group B was significantly more than groups C and D (P<0.05) . The number of Caspase-3 positive cells of group C was significantly more than that of group D at 3, 7, and 14 days (P<0.05) . While the number of TUNEL positive cells of group C was significantly more than that of group D at 3 and 7 days (P<0.05) . And the number of Caspase-3 positive cells and TUNEL positive cells was positively correlated in groups B, C, and D (P<0.05) at 1, 3, 7, 14, and 21 days after injury. ConclusionsLow-dose MTX may effectively reduce the degree of the secondary injury of spinal cord by reducing the nerve cell apoptosis. Better effect can be obtained when MTX is used as prevent method than as a way of treatment.
ObjectiveTo investigate the expression and correlation of hypoxia inducible factor 1α (HIF-1α) and autophagy related molecules (Beclin1 and LC3B) in rat nucleus pulposus cells under hypoxia in vitro.MethodsThe nucleus pulposus cells were extracted from the nucleus pulposus of healthy adult Sprague Dawley rats and passaged. The 3rd generation cells were identified by HE staining and collagenase type Ⅱ immunofluorescence staining and randomly divided into 4 groups. The cells in group A were cultured for 8 hours under normal oxygen condition (37℃, 5%CO2, 20%O2); the cells in group B were cultured for 8 hours under hypoxia condition (37℃, 5%CO2, 1%O2); the cells in group C were transfected with HIF-1α-small interfering RNA and cultured for 8 hours under hypoxia condition; and the cells in group D were cultured with autophagy inhibitor 3-MA for 8 hours under hypoxia condition. Western blot and real-time fluorescence quantitative PCR (qRT-PCR) were used to detect the expressions of HIF-1α and autophagy related molecules (Beclin1 and LC3B) in all groups.ResultsHE staining of the 3rd generation nucleus pulposus cells showed that the cytoplasm was light pink and the nucleus was blue black, and the collagenase type Ⅱ immunofluorescence staining was positive. Western blot and qRT-PCR results showed that the relative expressions of HIF-1α, Beclin1, and LC3B proteins and genes in group B were significantly higher than those in group A (P<0.05); the relative expressions of HIF-1α, Beclin1, and LC3B proteins and genes in group C were significantly lower than those in group B (P<0.05). There was no significant difference in the relative expression of HIF-1α protein and gene between groups B and D (P>0.05); while the relative expressions of Beclin1 and LC3B proteins and genes in group D were significant lower than those in group B (P<0.05).ConclusionHypoxia can induce the expressions of HIF-1α and autophagy related molecules (Beclin1 and LC3B) in rat nucleus pulposus cells, and HIF-1α in rat nucleus pulposus cells under hypoxia is related to the expression of autophagy related molecules, that is, down-regulation of HIF-1α can significantly reduce the expression of autophagy related molecules, while the down-regulation of autophagy levels under hypoxia has no or little effect on the expression of HIF-1α.
ObjectiveTo explore the protective effects of sodium valproic acid (VPA) on oxidative stress injury of osteoblasts induced by carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and its mechanism. Methods Osteoblasts were isolated from the skulls of 10 newborn Sprague Dawley rats and cultured by tissue block method, and the 1st generation cells were identified by alkaline phosphatase (ALP) and alizarin red staining. The 3rd generation osteoblasts were cultured with 2-18 μmol/L CCCP for 2-18 minutes, and cell counting kit 8 (CCK-8) was used to detect the cell survival rate. An appropriate inhibitory concentration and culture time were selected for the preparation of osteoblasts oxidative stress injury model based on half maximal concentration principle. The cells were cultured with 0.2- 2.0 mmol/mL VPA for 12-72 hours, and CCK-8 was used to detect cell activity, and appropriate concentration was selected for further treatment. The 3rd generation cells were randomly divided into 4 groups, including blank control group (normal cultured cells), CCCP group (the cells were cultured according to the selected appropriate CCCP concentration and culture time), VPA+CCCP group (the cells were pretreated according to the appropriate VAP concentration and culture time, and then cultured with CCCP), VPA+CCCP+ML385 group (the cells were pretreated with 10 μmol/L Nrf inhibitor ML385 for 2 hours before VPA treatment, and other treatments were the same as VPA+CCCP group). After the above treatment was complete, the cells of 4 groups were taken to detect oxidative stress indicators [reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA)], cell apoptosis rate, ALP/alizarin red staining, and the relative expressions of osteogenic related proteins [bone morphogenetic protein 2 (BMP-2), RUNX2], anti-apoptotic family protein (Bcl2), apoptotic core protein (Cleaved-Caspase-3, Bax), channel protein (Nrf2) by Western blot. Results The osteoblasts were successfully extracted. According to the results of CCK-8 assay, the oxidative stress injury model was established by 10 μmol/L CCCP cultured for 10 minutes and 0.8 mmol/mL VPA cultured for 24 hours was selected for subsequent experiments. Compared with blank control group, the activity and mineralization capacity of osteoblasts in CCCP group decreased, the contents of ROS and MDA increased, the activity of SOD decreased, and the apoptosis rate increased. Meanwhile, the relative expressions of BMP-2, RUNX2, and Bcl2 decreased, and the relative expressions of Cleaved-Caspase-3, Nrf2, and Bax increased. The differences were significant (P<0.05). After further VPA treatment, the oxidative stress damage of osteoblasts in VPA+CCCP group was relieved, and the above indexes showed a recovery trend (P<0.05). In VPA+CCCP+ML385 group, the above indexes showed an opposite trend (P<0.05), and the protective effects of VPA were reversed. Conclusion VPA can inhibit the CCCP-induced oxidative stress injury of osteoblasts and promote osteogenesis via Keap1/Nrf2/Are pathway.
ObjectiveTo investigate regulation mechanism of glypican-3 (GPC3) on Hippo signaling pathway and its effects on biological behavior of hepatocellular carcinoma Huh7 cells. MethodsShort hairpin RNAs (shRNA) targeting GPC3 and Yes-associated protein 1 (YAP1) genes were constructed. All of the shRNAs were transfected into Huh7 cells by liposome transfection in order to screen out the stable expression cell lines. The expressions of GPC3 and YAP1 in Huh7 cells were detected by PCR and Western blot in order to screen out the effective shRNAs. The proliferation, invasion, and apoptosis of Huh7 cells were detected by Edu cell proliferation assay, transwell, and flow cytometry. GPC3 shRNA transfection experiments were divided into 6 groups:non-transfection group, empty vector group, GPC3-714-shRNA group, GPC3-647-shRNA group, GPC3-1718-shRNA group, and GPC3-2134-shRNA group. YAP1 shRNA transfection experiments were divided into 6 groups:non-transfection group, empty vector group, YAP1-906-shRNA group, YAP1-1363-shRNA group, YAP1-1666-shRNA group, and YAP1-2895-shRNA group. GPC3 regulation experiments were divided into 5 groups:non-transfection group, empty vector group, GPC3-1718-shRNA group, GPC3-1718-shRNA+ rhYAP1 group, and YAP1-1666-shRNA group. Results① GPC3-1718-shRNA and YAP1-1666-shRNA plasmids were successfully constructed to silence the expressions of GPC3 and YAP1. ② The expressions of GPC3 mRNA and protein in each transfection group were significantly lower than those in the non-transfection group (P<0.05) and the empty vector group (P<0.05), while which in the GPC3-1718-shRNA group was significantly lower than those in all the other transfection groups (P<0.05). The expressions of YAP1 mRNA and protein in each transfection group were significantly lower than those in the non-transfection group and empty vector group (P<0.05), while which in the YAP1-1666-shRNA group was significantly lower than those in all the other transfection groups (P<0.05). ③ The expressions of YAP1 mRNA and protein in the GPC3-1718-shRNA group and the YAP1-1666-shRNA group were significantly lower than those in the non-transfection group (P<0.05) and the empty vector group (P<0.05), while which in the GPC3-1718-shRNA+rhYAP1 group were significantly higher than those in the GPC3-1718-shRNA group (P<0.05) and the YAP1-1666-shRNA group (P<0.05). ④ Compared with the non-transfection group and the empty vector group, the abilities of cell proliferation and invasion in the GPC3-1718-shRNA group and the YAP1-1666-shRNA group were significantly decreased, and the cell apoptosis was significantly increased (P<0.05); The cell proliferation, invasion, and apoptosis in the GPC3-1718-shRNA+rhYAP1 group were significantly improved (P<0.05). ConclusionGPC3 is likely to affect biological behavior of hepatocellular carcinoma Huh7 cells through regulation of YAP1 in Hippo signaling pathway.
ObjectiveTo investigate the role of p22phox and NOX5 in autophagy and apoptosis of osteoblasts induced by hypoxia.MethodsThe skull tissue of newborn rats was cut into small pieces, and the osteoblasts were separated and purified by the tissue block adherent method and the differential adherent method. The first generation cells were harvested and identified by HE staining, Alizarin red staining, alkaline phosphatase (ALP) staining, and flow cytometry. A three-gas incubator was used to prepare a hypoxia model of osteoblasts. At 0, 3, 6, 12, and 24 hours of hypoxia, the expressions of p22phox, NOX5, and LC3Ⅱ/Ⅰ were detected by Western blot, and the level of reactive oxygen species (ROS) and cell apoptosis rate were detected by flow cytometry. And the time point of the highest level of ROS was selected as the hypoxia time point for subsequent experiments. The first generation osteoblasts were divided into normal group, si-p22phox hypoxia group, and si-NOX5 hypoxia group and subjected to corresponding transfection and hypoxia treatment. The inhibition efficiency of si-p22phox and si-NOX5 were detected by RT-PCR. Then the osteoblasts were divided into normal group, si-NC hypoxia group, si-p22phox hypoxia group, and si-NOX5 hypoxia group. After transfection and hypoxia treatment, Western blot was used to detect the expressions of p22phox, NOX5, autophagy-related proteins (LC3Ⅱ/Ⅰ, Beclin), and apoptosis-related proteins (Bcl-2, Bax), and flow cytometry was used to detect the cell apoptosis rate and level of ROS. The first generation osteoblasts were divided into a hypoxia group for 12 hours (hypoxia group) and a group that simultaneously inhibited si-p22phox and si-NOX5 and hypoxia for 12 hours (inhibition+hypoxia group). The expressions of Beclin and Bax were observed by immunofluorescence staining after the corresponding treatment.ResultsAfter identification, the isolated cells were osteoblasts. After hypoxia treatment, the relative expressions of p22phox, NOX5, and LC3Ⅱ/Ⅰ proteins and the apoptosis rate of osteoblasts gradually increased (P<0.05), and the level of ROS also significantly increased (P<0.05) and reached the peak value at 12 hours. The 12-hour hypoxia model was selected for subsequent experiments. Silencing the p22phox gene did not affect the expression of NOX5, and silencing the NOX5 gene did not affect the expression of p22phox. Compared with hypoxia treatment, the relative expressions of LC3Ⅱ/Ⅰ, Beclin, and Bax proteins after inhibiting the expression of p22phox or NOX5 gene significantly decreased (P<0.05), the relative expression of Bcl-2 protein significantly increased (P<0.05), the cell apoptosis rate and level of ROS also significantly decreased (P<0.05). After silencing the expressions of p22phox and NOX5 genes at the same time, the immunofluorescence staining showed that the fluorescence of Beclin and Bax were weak.ConclusionInhibiting the expressions of p22phox and NOX5 genes can reduce the level of ROS in osteoblasts under hypoxia-induced conditions, and at the same time reduce autophagy and apoptosis, especially attenuate the excessive apoptosis of cells in the early to late stages, and strengthen the hypoxic osteoblasts proliferation.