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Objective:To investigate the effects of cyclic tensile stress on the function and degeneration of nucleus pulposus cells.Methods:The human primary nucleus pulposus cells were isolated and cultured. The cyclic tensile stress (100 000 μ?, 10% tensile strain, 0.1 Hz, 8 640 cycles) was loaded on the cells for 24 h. The proliferation of the cells was examined by MTT method. The cell cycle and apoptosis were detected through flow cytometry. Gene expression profile chip was used to detect the differentially expressed genes between the tensile stress group and control group. The function of these gene was analyzed by bioinformatics. The expression of inflammatory related factors, TGF-β, matrix degrading enzymes and extracellular matrix molecules were examined by qRT-PCR.Results:The cyclic tensile stress significantly promoted proliferation and cell cycle of nucleus pulposus cells. The cell percentage of S phase ( t=5.336, P<0.05) and G2/M phase ( t=7.288, P<0.01) was significantly different between the tensile stress group and control group. The cyclic tensile stress inhibited apoptosis of nucleus pulposus cells (8.56%±0.48% vs 10.63%±0.32%, t=4.474, P<0.05). A total of 866 differentially expressed genes were detected. Gene ontology analysis showed the roles of these genes in cells including focal adhesion, extractable matrix, membrane raft, condensed chrome kinetochore, cytoskeleton, etc. The cyclic tensile stress significantly affected the mRNA expression of inflammatory related factors, TGF-β genes, matrix proteinase and extracellular matrix molecules. Compared with the control group, the mRNA expression of inflammatory related factors IL15 ( t=5.379, P<0.05), IGF1 ( t=5.454, P<0.05) and IGFBP7 ( t=13.57, P<0.01) were significantly decreased in the tensile stress group; The mRNA expression of TGF-β genes TGFB1 ( t=6.931, P<0.05), TGFB2 ( t= 15.56, P<0.01) and TGFB3 ( t=7.744, P<0.05) were significantly increased in the tensile stress group; The mRNA expression of matrix proteinase ADAMTS3 ( t=5.241, P<0.05) and MMP19 ( t=24.72, P<0.01) were significantly decreased, and TIMP3 ( t=8.472, P<0.01) increased in the tensile stress group; The mRNA expression of extracellular matrix molecules COL2A1 ( t=5.871, P<0.05), FLRT2 ( t=5.216, P<0.05) and FN1 ( t=4.289, P<0.05) were significantly increased. Conclusion:The cyclic tensile stress promoted cell cycle and proliferation and inhibited apoptosis of nucleus pulposus cells. The cyclic tensile stress may affect the function and degeneration of nucleus pulposus cells by regulating the expression of inflammatory related factors, TGF-β, matrix degradation enzymes and ECM molecules.
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AIM:To investigate the effect of renal denervation ( RDN) by radiofrequency catheter ablation on the expression of aquaporins ( AQP) in dog kidneys .METHODS:Adult Chinese Kunming dogs ( n=12 ) were randomly divided into RDN group and control group (6 for each group).The dogs in RDN group underwent bilateral RDN using ra-diofrequency catheter ablation , and radiofrequency catheter was positioned in bilateral renal artery without ablation in con -trol group.The levels of norepinephrine (NE) and AQP1~3 in the renal tissues were detected 1 month after RDN, and blood pressure (BP) measurements were performed at baseline and 1 month after RDN.RESULTS: The level of NE in RDN group was significantly lower than that in control group (P<0.01).The expression of AQP1~3 in the renal cortex and medulla was lower in RDN group than that in control group .RDN also caused a substantial BP reduction (P<0.05). CONCLUSION:RDN substantially decreases the tissue levels of NE and AQP in dog kidneys , and also decreases BP sig-nificantly , which might be involved in the mechanism of BP reduction by RDN .Renal sympathetic nerve plays an excitatory role in the regulation of AQP in the kidney.
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Objective To investigate the effect of isoflurane preconditioning on Toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88) signaling pathway in ischemic penumbra following focal cerebral ischemia-reperfusion (I/R) in rats.Methods Fifty-four healthy male SD rats,aged 3 months,weighing 250-280 g,were randomly divided into 3 groups (n =18 each):sham operation group (group S),I/R group and isoflurane preconditioning group (group IP).Focal cerebral I/R was induced by middle cerebral artery occlusion.In groups I/R and IP,a nylon thread with rounded tip was inserted into the right internal jugular vein and threaded cranially until resistance was met.The middle cerebral artery was occluded for 2 h,followed by 24 h reperfusion.In group IP,the animals inhaled 2.0％ isoflurane for 2 h,and middle cerebral artery occlusion was performed at 24 h after the end of preconditioning.Neurological deficit was scored at 24 h of reperfusion and then the rats were sacrificed.Five rats in each group were chosen and the brains removed for measurement of the cerebral infarct volume.The right cerebral ischemic penumbra was removed for detection of the expression of HSP60,TLR4,MyD88 protein and mRNA by Western blot analysis and real time-PCR.Apoptosis was detected in the ischemic penumbra in the left 3 rats in each group using TUNEL.Apoptosis index (AI) was calculated.Results Neurological deficit scores and AI were significantly increased,the cerebral infarct volume was significantly enlarged,and the expression of HSP60,TLR4,MyD88 protein and mRNA was up-regulated in groups I/R and IP as compared with group S ( P ＜ 0.05).Isoflurane preconditioning significantly reduced the cerebral infarct volume and decreased neurological deficit scores and AI,and down-regulated the expression of HSP60,TLR4,MyD88 protein and mRNA (P ＜ 0.05).Conclusion The mechanisn by which isoflurane preconditioning protects ischenic penumbra following focal cerebral I/R may be related to inhibition of TLR4-MyD88 signaling pathway.
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Objective To investigate the effect of isoflurane preconditioning on the expression of 5-lipoxy-genase (5-LOX) during focal cerebral ischemia-reperfusion (I/R) in rats.Methods Thirty-nine male adult Sprague-Dawley rats weighing 250-300 g were randomly divided into 3 groups (n =13 each):sham operation group (group S); focal cerebral I/R group (group I/R); isoflurane preconditioning group (group Ⅰ).Focal cerebral I/R was produced by mid-cerebral artery occlusion in anesthetized rats.The rats inhaled 2 h of 2％ isoflurane and focal cerebral I/R was produced 24 h later in group I.The neurological deficits were scored at 24 h of reperfusion.The animals were then sacrificed.The brains were immediately removed for determination of the infarct size.The expression of 5-LOX,myeloid differentiation factor88 (MyD88) and nuclear factor kappa B (NF-κB) protein and mRNA was detected using Western blot and RT-PCR respectively.Results Compared with group S,the neurological deficit score was significantly increased,the infarct size was enlarged in groups I/R and I,the expression of 5-LOX,MyD88 and NF-κB protein and mRNA was up-regulated in group I/R,and the expression of 5-LOX mRNA and MyD88 protein and mRNA was up-regulated in group I (P ＜ 0.05).Compared with group I/R,the neurological deficit score was significantly lower,the infarct size was smaller,and the expression of 5-LOX,MyD88 and NF-κB protein and mRNA was lower in group I (P ＜ 0.05).Conclusion Isoflurane preconditioning can reduce focal cerebral I/R injury by down-regulating the expression of 5-LOX and inhibiting MyD88/NF-κB signaling pathway in rats.
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BACKGROUND: Acellular bladder submucosa is a natural extracellular matrix, which is mainly composed of collagen Ⅰ and Ⅲ. It is regarded as an ideal biological scaffold material. OBJECTIVE: To evaluate the biocompatibility of acellular bladder submucosa as a tissue engineered scaffold material. METHODS: Pig urinary bladder was immersed in the solution of PBS and sodium azide for a night, and the mucosa was removed. Acellular bladder submucosa was prepared using continuous hypotension, freeze-thawed treatment and NaOH spallation. The biocompatibility of acellular bladder submucosa was evaluated through histologic structure, DNA residual, cytotoxicity, cell adhesion, as well as subcutaneous inflammatory reactions. RESULTS AND CONCLUSION: The cell components were completely eliminated after deoellularization treatment, while the extracellular matrix was remained intact as normal bladder:According to MTT results, cytotoxicity of acellular bladder matrix was assigned to be the first grade. No DNA signal was observed after extraction, and the matrix also supported porcine smooth muscle cell attachment and proliferation. Subcutaneous implantation of the matrix indicated that the acellular bladder submucosa trigger no immunologic rejection reaction obviously. The results demonstrated that: the acellular bladder submucosa prepared here exhibits excellent biocompatibility, which can be used as substitution in tissue-engineering field.