Promoting effect of 810 nm low-level laser on axonal regeneration of neurons in mice with spinal cord injury and its related mechanism / 中华创伤杂志

Objective To investigate the effect of 810 nm low-level laser on neuronal axonal regeneration of mice with spinal cord injury and its related mechanism.Methods In vivo experiment:20 Balb/c mice were randomly divided into the spinal cord injury group(SCI group)and the 810 nm low-level laser irradiation group(low-level laser group)after spinal cord injury according to the random number table method,with each group containing ten mice.A mice SCI model was established through clamp injury and the low-level laser group continuously irradiated the damaged area with weak 810 nm low-level laser with selected parameters(continuous wave with wave length 810 nm,power density 2 mW/cm2,spot are 4.5 cm2,irradiation time 50 minutes,energy 6000J/cm2).Then immunofluorescence staining was used to observe the M1 macrophage marker-inducible nitric oxide synthase(iNOS),the M2 macrophage marker arginase 1(Arg-1)and the universal marker F4/80 of macrophages after 14 days.Furthermore,in the in vitro experiment,standardized low-level laser-macrophage irradiation model was established.Another 20 Balb/c mice were used to obtain primary bone marrow-derived macrophages which were induced into M1 macrophages using lipopolysaccharide(LPS)and interferon-gamma(INF-γ).The M1 macrophages were randomly divided into the M1 macrophage group(M1 group)and the low-level laser therapy group(M1 + low-level laser group)equally according to the random number table method.The M1 group was not treated,and the M1 + low-level laser group was treated with low-level laser of selected parameters.RT-qPCR and ELISA were used to detect the expression of interleukin-1 receptor antagonist(IL-1RA)and interleukin-10(IL-10)in M1 macrophages 24 hours after irradiation.Western blot was used to analyze the expression of iNOS,Arg-1,differentiation antigen cluster 206(CD206),protein kinase B(AKT),phosphorylated protein kinase B(p-AKT),cyclic adenosine response element binding protein(CREB)and phosphorylated cyclic adenosine response element binding protein(p-CREB)in M1 macrophages 48 hours after irradiation.Dorsal root gangtion neurons(DRG)were cultured in two groups of macrophage conditioned medium,and the length of DRG axon growth was measured 48 h later to evaluate the effect of low-level laser on neuronal axon growth.Results In the in vivo experiment,compared with mice with spinal cord injury alone,the fluorescence intensity of F4/80+ iNOS+ in the spinal cord injury area decreased(1.00±0.08vs. 0.06±0.04)(P＜ 0.05)and the fluorescence intensity of F4/80 + Arg-1 + increased after low-level laser(1.00±0.07vs.2.15±0.12)(P＜0.01).In the in vitro experiment,compared with the M1 group,the expression of the M1 macrophage marker iNOS in the M1 + low-level laser group decreased(1.00±0.11 vs.0.08±0.01)(P＜ 0.01);the M2 macrophage marker Arg-1(1.00±0.14vs.2.44±0.16)(P＜0.01),and the expression of CD206(1.00±0.12 vs.1.83±0.05)(P＜0.01)increased.In addition,IL-1RA expression was increased in the M1 + low-level laser group compared with the M1 group(RT-qPCR:1.00±0.00vs.2.27±0.22)(P＜0.01)(ELISA:1435.58±100.48vs.2006.12±123.91(P＜0.05);IL-10 expression was also increased in the M1 +low-level laser group compared with the M1 group(RT-qPCR:1.00±0.00 vs. 3.45±0,56)(P＜0.05)(ELISA:137.13±4.20 vs.188.29±8.49)(P＜ 0,01);compared with the M1 group,the macrophage polarization pathway protein in the M1 + low-level laser group increased,AKT(1.07±0.12vs.1.74±0.04)(P＜0.01),p-AKT(1.00±0.12 vs.1.64±0.15)(P＜0.05),p-CREB(1.00±0.10vs.2.12±0.18)(P＜0.01).Compared with the M1 group,the conditioned medium of the M1 + low-level laser group significantly promoted DRG axon growth(567.66±63.59 vs.1068.95±130.14)(P＜ 0,05).Conclusions The 810 nm low-level laser irradiation can promote neuronal axon regeneration of mice with spinal cord injury,which may be related to the regulation of macrophage polarization phenotype by low-level laser through AKT/CREB pathway.

Resting-state functional magnetic resonance imaging of first-onset major depressive disorder: analysis of 18 cases / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the changes in brain regional homogeneity in first-onset major depressive disorders (MDDs) using resting-state functional magnetic resonance imaging (fMRI).</p><p><b>METHODS</b>Eighteen patients with first-onset MDDs and twenty gender- and age-matched healthy controls underwent resting-state fMRI scans to compare the regional homogeneities of the brain regions.</p><p><b>RESULTS</b>Compared with the normal controls, the patients with MDDs showed significantly decreased regional homogeneity in the left posterior cingulated gyrus, bilateral inferior temporal gyrus, bilateral superior temporal gyrus, left inferior frontal gyrus, left hippocampa gyrus, left posterior central gyrus, left angular gyrus, right amygdala, right orbital frontal gyrus, right supplementary motor area, and right cerebellar lobe.</p><p><b>CONCLUSION</b>Patients with first-onset MDDs have dysfunctions in the brain regions closed related with cognition and emotional control.</p>

Genipin crosslinked preparation of new peripheral nerve tissue engineered scaffolds and comparison of their biological characteristics / 中华创伤杂志

Objective To compare biological properties of ehitosan composite artificial neural type Ⅰ collagen scaffold material cross-linked with ultraviolet rays (UV), genipin (GP) and glutaraldehyde (GTA) in aspects of uhrastrueture, porosity, swelling rate, degradation rate, crosslinking degree and cytotoxicity. Methods (1) According to different cross-linking methods, biomaterials were divided into three groups, ie, UV group, GP group and GTA group. (2)The mierostrueture of three groups was observed under scanning electron microscope (SEM) to measure pore size, porosity rate and pore-size distribution. (3)Swelling rate and in vitro degradation rate:the biomaterials were weighed (W_0) after crosslinking and then immersed in culture medium containing 10 ml aseptic phosphate buffer solution (PBS). The samples were drawn from the culture medium after 24 hours, wiped with filter paper to remove excess liquid and weighed (W_1). Swelling rate(%) = W_1-W_0/W_0×100%. The remaining sampies from each group were weighed (W_2) at 4, 8, 12 weeks with the same procedure. Degradation rate (%) = W_1-W_2/W_1×100%. (4)Determination of cross-linking index: 10 samples were prepared from each group, five samples from which were reacted with trinitro-benzen-sulfonic acid(TNBS)and sodium bicarbonate and then were hydrolyzed with hydrochloric acid. The absorbance of the diluted solution was measured at 346 nm. The other five samples were prepared by the same procedure, except for hydrochloric acid was added before addition of TNBS, when the absorbance was measured as control (A_(control)). The absorbance after crosslinking:A_(after)=ATNBS-A_(control). Another 10 samples without any crosslinking were detected with the same procedure to measure the absorbance before crosslinking (A_(before)). Crosslinkiag index = (A_(before)-A_(after))/A_(before)×100%. (5) Determination of cytotoxicity : two international standard experimental methods were adopted in the study according to experimental principle of GB/T 16886-ISO 10993 on medical apparatus. L929 fibroblasts of mouse were used for in vitro experimental study of cytotoxicity of modified scaffold. Results The biomaterials without any cross-linking were circular cylinder, with parallel arranged microscopic channel and uniform pore size of 30-120 μm. The pore size of UV group remained basically unchanged, while the pore size in GP group and GTA group was smaller than that in UV group. (2) The porosity rate in GP group and GTA group was higher than that in UV group, but there was no statistical difference between GP group and GTA group. The swelling rate of GP group was higher than that GTA group, which was higher than UV group. (3)The crosslinking index of GP group and GTA group were 55.3% and 82.5%. (4) No statistical difference was found in regard of in vitro degradation rate after GP group and GTA group were put in PBS for4, 8 and 12 weeks, respectively. But in vitro degradation rate in UV group was significantly higher than that in GP group and GTA group. (5) Cell culture in GTA group presented partial necrosis, while cells cultured in GP group and UV group grew well. Conclusion Collagen/chitosan scaffolds cross-linked with GP have sound biostability and good biocompatibility and hence are potential alternatives for nerve tissue engineering.

Influence of sodium fluoride on alkaline phosphatase activity and bone gla protein synthesis in human yellow ligament cells in vitro / 中华骨科杂志

Objective To investigate the influence of sodium fluoride(NaF)on alkaline phosphatase (ALP)activity and bone gla protein(BGP)synthesis in yellow ligament cells from different surgical simples in vitro.Methods The human ligament cells were divided into three groups according to its sources,including normal yellow ligament cells(NLF)group(from acute traumatic thoracolumbar fractures with paraplegia in 7 patients),degenerative yellow ligament cells(DLF)group(from degenerative lumbar stenosis in 9 cases)and ossified ligament cells(OLF)group(thoracic yellow ligament from 8 patients).Twenty-four groups of cells were obtained under vitro cell culture by the method of tissue adherence.Different concentrations of NaF were added into the medium when the cells spread to the fifth generation.Then,the morphological changes were observed and ALP activity and BGP synthesis were tested.Results Human yellow ligament cells from different samples can proliferate and be passaged in vitro.The cell in ossific groups and degenerative groups were pleomorphic and could form calcium nodules.High concentration of NaF(1.0 mmol/L)can lead to cytotoxic reaction in all 24 groups.Low concentrations of(0.01-0.125 mmol/L)NaF can enhance the ALP activity and BGP synthesis in DLF groups while no effect was found in OLF and NLF groups cells under the same concentration of NaF.Conclusion The fact that fluoride can promote ALP activity and BGP synthesis in degenerative yellow ligament cells in vitro indicates fluoride may play an important role in inducing further ossification of human ligament cells.