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Background Silica nanoparticles (SiNPs) enter the human body through respiratory tract, digestive tract, and skin, causing body damage. Lung is one of the main damaged organs. Objective To observe the expressions of complement activated fragment C3a and its receptor C3aR in the lungs of mice exposed to SiNPs through respiratory tract, and to explore the involvement of C3a/C3aR in lung injury induced by SiNPs exposure. Methods The ultrastructure of SiNPs (particle size 5-20 nm) was determined under a transmission electron microscope, and the hydrodynamic diameter and surface Zeta potential of SiNPs were determined using a nanoparticle size analyzer. A total of 88 SPF C57BL/6J mice were randomly divided into five groups: a blank control group without any treatment (14 mice), a vehicle control group treated with 50 μL stroke-physiological saline solution by intratracheal instillation (14 mice), and three SiNPs exposure groups (low-dose group, medium-dose group, and high-dose group with 20 mice in each group, who were given 50 μL SiNPs suspension of 7, 21, and 35 mg·kg−1 respectively and exposed once every 3 days for 5 times). The mice were anesthetized on day 1 (1-day model group) and day 15 (15-day model group) after exposure, then sacrificed after extraction of bronchoalveolar lavage fluid (BALF), and lung tissues were retained. The morphological changes of lung tissues were observed by HE staining, the expression level of C3a in BALF was detected by enzyme-linked immunosorbent assay, the deposition of C3a and C3aR in lung tissues were observed by immunohistochemistry, the protein expression level of C3aR was determined by Western blotting, and the localization and semi-quantitative detection of C3a and C3aR in lung tissues was observed by immunofluorescence. Results SiNPs agglomerated in stroke-physiological saline solution. The average hydrodynamic diameter was (185.60±7.39) nm and the absolute value of Zeta potential was (43.33±0.76) mV. The condition of mice in the 1-day model group and the 15-day model group was good, while 2 mice died in the medium-dose group of the 1-day model group due to misoperation. The autopsy results of the two mice showed congestion of the lung tissue, emphysema, and no imperfection of trachea integrity. No death was observed in other dose groups. The HE staining results showed pathological damage to the mouse lung, including alveolar wall thickening and inflammatory cell infiltration after SiNPs exposure. The pathological damage became more serious with the increase of dose. Regarding pathological changes, the 15-day model group was slightly relieved compared with the 1-day model group, but there were still pathological changes. The enzyme-linked immunosorbent assay results showed that there was no difference in the expression level of C3a between the blank control group and the vehicle control group (P＞0.05), the expression levels of C3a in the medium-dose group and the high-dose group were significantly higher than that in the vehicle control group (P<0.05). The immunohistochemistry results showed that C3a deposition was consistent with the enzyme-linked immunosorbent assay results. The Western blotting and the immunohistochemistry results showed that C3aR expression was low in the blank control group and the vehicle control group, while the expression in each dose group tended to increase with the increase of dose. The immunofluorescence results showed that the fluorescence signals of C3a and C3aR were weak in the blank control group and the vehicle control group in the 1-day model group and the 15-day model group, while the fluorescence signals in the lung tissues of mice in the SiNPs exposure groups tended to increase with the increase of dose. Conclusion The increased expressions of C3a and C3aR in complement activation may be related to lung injury induced by intratracheal instillation of SiNPs, suggesting that C3a/C3aR may be involved in lung injury induced by SiNPs exposure.
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Objective:To investigate the effects of complement C3a receptor(C3aR) and receptor for advanced glycation end product(RAGE) on bone metabolism in APP/PS1 mice model of Alzheimer′s disease.Methods:Alzheimer′s disease model APP/PS1 mice was hybridized with C3aR knockout mice(C3aR -/-), RAGE knockout mice(RAGE -/-) to generate APP/PS1-C3aR -/- and APP/PS1-RAGE -/-, respectively. In vivo, micro computed tomography(Micro-CT) scan, bone tissue osteocalcin immunohistochemical staining, tartrate-resistant acid phosphatase(TRAP) staining and Goldner′s trichrome staining were used to understand the variabilities of bone metabolism between different genotypes of mice; In vitro, bone marrow-derived osteoblast and osteoclast induction cultures were used to understand the effects of C3aR and RAGE on osteoblast and osteoclast differentiation. Results:In in vivo experiments, APP/PS1-C3aR -/- and APP/PS1-RAGE -/- mice showed increased bone mass, increased bone formation, decreased bone resorption, and increased osteoid compared to APP/PS1 mice( P<0.05). In in vitro experiments, bone marrow mesenchymal stem cells(BMSCs) derived from APP/PS1-C3aR -/- and APP/PS1-RAGE -/- mice showed enhanced osteoblast differentiation and elevated expression levels of alkaline phosphatase(ALP) and runt-related transcription factor 2(RUNX2), diminished osteoclast differentiation, and reduced positive TRAP staining( P<0.05). Conclusions:Both C3aR and RAGE are involved in regulating the process of APP/PS1 bone metabolism. Knockout of C3aR and RAGE can improve osteoporosis in APP/PS1, providing a new target for the clinical treatment of Alzheimer′s disease combined with osteoporosis.
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Aim To explore the effeets of Salvianolie aeirl A (SAA) on platelet recruitment, activation and neutrophils in heart of myocardial infarction ( Ml ) mice.Methods C57BL/6 mice were randomly divid¬ed into: Sham operation group.Ml model group, SAA (5, 10 mg • kg 1 ) group, tirofiban (Tirofiban, 0.87 mg • kg ' ) group, using tail vein injection for 3 d.Echocardiography and HE staining were used to detect mouse heart function and infarct area; 1HC, FCS, ELISA, Western blot and other methods were used to explore the inhibitory effect of SAA on platelet and neutrophil activation.Results Compared with Ml group, SAA could improve the cardiac function and cardiac physiology changes of Ml mice, reduce the ex¬pression of CD42c in myocardial tissue and CD62p in peripheral blood without affecting tail bleeding time, reduce ADP-induced platelet activation and increase p- VASP/VASP ratio, reduce the ratio of p-PI3K/PI3K and p-AKT/AKT, reduce the expression of CD45, Ly6G, CXCL1 and CXCL2 in myocardial tissue, re¬duce the expression of complement component C3aR in myocardial tissue, and reduce C3a-induced NE and MPO, MMP9, LF level.Conclusions SAA has an anti-platelet activation effect by inhibiting the PI3K/ AKT and VASP pathways and an anti-neutrophil acti¬vation effect by inhibiting the expression of C3aR and C3a.
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Objective@#To explore the effect of complement C3 a-C3a receptor in the kidney immune inju-ry in trichloroethylene-sensitized mice by using C3a receptor specific antagonist C3aRA and discuss the patho-genesis of kidney injury in occupational dermatitis medicamentosa-like of trichloroethylene (ODMLT) .@*Methods@#42 female 6~8 weeks old BALB/c mice of specific pathogen free were randomly divided into blank control group (5) , solvent control group (5) , TCE treatment group (16) and TCE+C3aRA treatment group (16) . The TCE treat-ment group and TCE+C3aRA treatment group were further divided into the sensitized group and the non-sensi-tized group according to the skin sensitization test score. Renal function was detected by biochemical detection kit; expression of C3aR in kidney tissue was detected by qPCR; expression of IL-1β and TNF-α protein were de-tected by immunohistochemical.@*Results@#Compared with solvent control group and corresponding non-sensitized group, CRE and BUN in TCE sensitized group and TCE + C3aRA sensitized group were significantly increased (P<0.05) . Compared with TCE sensitized group, CRE and BUN in TCE+C3aRA sensitized group were signifi-cantly decreased (P<0.05) . Compared with solvent control group and TCE non-sensitized group, the expression level of C3aR gene in kidney tissue in TCE sensitized group was significantly increased (P<0.05) . There was a large number of IL-1β and TNF-α protein expression in kidney tissue in TCE sensitized group and TCE+C3aRA sensitized group. Compared with the TCE sensitized group, the expression level of IL-1β and TNF-α protein in kidney tissue in TCE+C3aRA sensitized group was significantly decreased (P<0.05) .@*Conclusion@#C3a-C3aR may be involved in the kidney immune injury in TCE sensitized mice, C3aRA has a protective effect on the kid-ney immune injury in TCE sensitized mice.
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Aim To investigate the effects of salidroside on NeuN and Egrs in the ischemic side of middle cerebral artery occlusion (MCAO) rats by inhibiting complement C3.Methods The rats were subjected to MCAO with suture-occluded method,and the neurologic injury was evaluated.The rats underwent l h ischemia/reperfusion with 1 d and 2d salidroside treatment,and the expressions of NeuN,Egr4,C3 and C1 were tested.Male Sprague Dawley rats were separately injected ventricle C3aR inhibitor and artificial cerebrospinal fluid with the help of ventricle stereotaxic apparatus.Thirty min later,the models of MCAO were finished with 1h reperfusion,drug administration and intracerebroventricular injection for 2d.The expressions of NeuN,Egr4,C3 were detected.Results Compared with models of MCAO,the expression of C3 in MCAO rats treated with salidroside 1 d and 2d decreased significantly,and the expression of NeuN increased markedly.Salidroside had no apparent effect on Egr4 and C1 of administration of 1d,but it could significantly enhance the expression of Egr4 after 2d,and reduce the expression of C1 significantly after 2d.The rats administrated with C3aR inhibitor into cerebral ventricle continueously showed the same result in accordance with the treatment of salidroside.And the treatment of salidroside and C3aR inhibitor did not show remarkable additive effects.Conclusion The neuroprotective effect of salidroside on acute cerebral ischemia/reperfusion injury may be related to the inhibition of the activation of the classical pathway of complement,the regulation of Egrs and the reduction of apoptosis.
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Objective The key points in the epithelial-mesenchymal transition ( EMT) procedure include the downregula-tion of epithelial protein (E cadherin) and the upregulation of cell activity and cell matrix generation .The aim of this study was to es-tablish a method for primary culture and identification of mouse renal tubular epithelial cells and to explore whether the activation of C3aR can induce epithelial-to-mesenchymal transition in mouse primary renal epithelial cells . Methods Murine renal tubular seg-ments were used for primary cell culture .Immunocytochemistry and immunofluorescence staining were used to identify the renal tubular epithelial cells.The experiment groups included control group , five different concentrations of C3aR agonist groups (0.1, 1, 100, 500, and 2000 ng/mL), and three different time-point groups.The mRNA levels of E-cadherin,α-smooth muscle actin (SMA) and colla-gen I in renal tubular epithelial cells were detected by Real-time PCR; the protein of E-cadherin, α-SMA were detected by Western blot.The cytoskeleton of epithelial cells was observed by phalloidin staining . Results Compared with the control group , the protein expression of E-cadherin deceased (0.950±0.901 vs 0.650±0.221) and the expression of α-SMA (1.380±0.062 vs 1.600±0.103) and collagen I increased in C3aR agonist group (500 ng/mL, after 48 hours) (P<0.05).In addition, the association between these changes and C3aR agonists was presented in a dose-and time-dependent man-ner, respectively.The cytoskeleton staining showed that treatment of renal tubular epithelial cells with C 3aR agonists induced the formation of actin stress fibers in a time-dependent manner . Conclusion The method for primary culture and identification of mouse renal tubular epithelial cells were successfully established .The activation of C3aR could induce epithelial-to-mesenchymal transition in mouse primary renal epithelial cells , which plays an essential role in the de-velopment of renal fibrosis .Moreover , this study indicated that C 3aR may become a new therapeutic target in kidney diseases .
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Objective Our previous study showed that the expression of C 3aR was increased in renal tubular epithelial cells (RTEC).However, the role of C3aR in diabetic nephropathy remains unknown, and so does the exact physiological and pathological signifi-cance of C3aR in relevant renal tissues.In the present study, we investigated the physiological and pathological significance of C3aR in RTECs using a lentivirus expression vector and anRTEC strain overexpressing C3aR. Methods Based on the sequence of C3aR mRNA, the human C3aR gene was synthesized and cloned into the multi-clonal site of the lentivirus expression vector pLenti6.3-MCS-IRES2-EGFP to construct a C3aR expression vector pLenti6.3-C3aR-IRES2-EGFP.After identification by sequencing, the recombinant lentivirus expressing C3aR was packaged by cotransfecting293T cellswith the recombinant lentivirusexpression vector and packaged plasmid .Then,the recombinant lentivirus was used to infect the human RTECline HK 2.After screening in the medium with blasticidin, blasticidinr-esistant cell clones were obtained, followed by identification ofthe human RTECline stably overexpressing C 3aR by real-time PCR and immunochemical staining. Results TheC3aR expression vector pLenti6.3-C3aR-IRES2-EGFP was successfully constructed and the sequence was proved to be correct. C3aR expression recombinant lentivirus was successfully packaged with a titer of 5×108/mL.Blasticidin-resistant HK2 cell clones were ob-tained and the expression of HK2-C3aR mRNA was significantly higherin the HK2-C3aR cells than in the non-transfected HK2 cells (2.33± 0.45 sv 1.00±0.09, P<0.05). Conclusion We successfully constructed a C3aR expression lentivirus vector pLenti6.3-C3aR-IRES 2-EGFP and a C3aR overexpression renal tubular epithelial cell strain HK2-C3aR, which is very contributive to further studies of the roles of C3aR in renal tubular epithelial cells and other types of cells.
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[Abstract ] Objective Evidence from previous studies indicated that over-activation of C3a/C3aR axis existed in the renal tubular epithelial cells of patients with renal diseases including diabetic nephropathy .However , the pathological significance of over-ac-tivating C3a/C3aR axis still remains to be elucidated .In this study, we constructed a renal tubular epithelial cell line over-expressing C3a in a secretory manner in order to provide a cell model to investigate the pathological significance of over -activating C3a/C3aR axis under various pathological scenes . Methods We designed a synthesized C3a secretory expression unit and cloned it into the multi-clonal site of lentivirus expression vector pLenti 6.3-MCS-IRES2-EGFP.After identification by sequencing , recombinant lentivirus was packaged by using pLenti 6.3-C3a-IRES2-EGFP and packaging plas-mid in 293T cells.Then, the recombinant lentivirus was used to in-fect HK2, a cell line of human renal tubular epithelial cells .After screening in medium with blasticidin , blasticidin resistant cell clones were obtained .Real-time PCR and ELISA method were applied to analyze the expression and secretion of stable transfected cells cloned C3a and identify renal tubular epithelial cell lines with stable over-activating C3a. Results ①C3a secretory expression unit was suc-cessfully synthesized and correctly cloned into the multi-clonal site of pLenti6.3-IRES2-EGFP; ②C3a secrectory expression recombi-nant lentivirus LV-C3a was successfully packaged with a high titer of 5 ×108/mL;③HK2 Cell clones resistant for blasticidin were ob-tained;according to the analysis of Real-time PCR and ELISA, the C3a mRNA level in HK2-C3a cell lines was significantly higher than that of HK2 cells(1.0 ±0.5 vs 1321.0 ±18.0, P<0.01) and the secreted C3a level increased significantly ([0.3 ±0.2]ng/mL vs [249.0 ±37.0] ng/mL, P<0.01). Conclusion The present study successfully constructed C 3a secretory expression vector pLenti6.3-C3a-IRES2-EGFP and C3a over-expression renal tubular epithelial cell line HK 2-C3a, which is very useful in further study of the function and significance of C 3a/C3aR axis not only in renal tubular epithelial cells but also in other cell types .