Expressions of type I collagen, α2 integrin and β1 integrin in sclera of guinea pig with defocus myopia and inhibitory effects of bFGF on the formation of myopia

AIM:To investigate the expressions of type I collagen, α2 integrin and β1 integrin in the posterior sclera of guinea pigs with defocus myopia and whether basic fibroblast growth factor (bFGF) injection inhibits the formation and development of myopia by upregulating the expression of type I collagen, α2 integrin and β1 integrin. METHODS:After 14 days of treatment, the refractive state and axial length were measured and the levels of type I collagen, α2 integrin and β1 integrin were assayed in the posterior sclerae of groups of guinea pigs that wore a monocular-7D polymethylmethacrylate (PMMA) lens or had -7D lens wear followed by the peribulbar injection of Phosphate Buffer Solution (PBS) or bFGF. The untreated fellow eye served as a control. Guinea pigs with no treatment served as normal group. ·RESULTS:The results showed that 14 days of monocular defocus increased axial eye length and refraction, while bFGF delivery inhibited them markedly. Further, it was also found that the monocular-7D lens could decrease the levels of type I collagen, α2 integrin and β1 integrin expressions, while, unlike PBS, bFGF increased them significantly in comparison to contralateral control eyes and normal eyes. CONCLUSION:bFGF can prevent the formation anddevelopment of defocus myopia by upregulating the expressions of type I collagen, α2 integrin and β1 integrin. Taken together, our results demonstrate that bFGF promotes sclera remodeling to prevent myopia in guinea pigs.

The effect of Nifedipine on the expression of type I collagen in gingival fibroblasts

Objective：To investigate the effect of nifedipine（calciumchannel blocker） on the expression of collagen in gingival fibroblasts invitro. Methods：Primarily gingival fibroblasts were cultured and incubated with various concentrations of nifedipine（108 μg/L, 360 μg/L and 1200 μg/L）for 5 days. Gingival fibroblasts were primarily cultured derived from nifedipine responders and nonresponders in the presence of 360 μg/L nifedipine. Enzyme-linked immunosorbent assay was used to evaluate the amount of type I collagen. Cell proliferation was measured by cell counting with evaluating MTT value. Results：The expressions of collagen and cell proliferation were significantly different among the high concentration groups and the others on the fifth day, especially higher in 360 μg/L and 1200 μg/L groups and also different among nifedipine responders and non-responders. Conclusion：The expression of collagen and cell proliferation may be concerned with the biological mechanism for gingival overgrowth.

Effect of chitosan/type I collagen/gelatin composites in biocompatibility and nerve repair

Chitosan, collagen I and gelatin were mixed in appropriate quantities to develop a new nerve repair material, with good arrangement and structure, as well as even aperture size. The composite material was sterilized by 60Co irradiation for 24 hours prior to implantation in the right thigh of rats following sciatic nerve damage. Results showed that the material was nontoxic to the kidneys and the liver, and did not induce an inflammatory response in the muscles. The composite material enhanced the recovery of sciatic nerve damage in rats. These experimental findings indicate that the composite material offers good biocompatibility and has a positive effect on injured nerve rehabilitation.

骨质疏松症患者PINP、25-(OH)VitD_(3)、BMP-2与中医辨证分型的相关性研究

目的:分析骨质疏松症患者血清总I型胶原氨基末端前肽(PINP)、25-羟维生素D3[25-(OH)VitD_(3)]及骨形态发生蛋白2(BMP-2)与其中医辨证分型的相关性。方法:收集我院2020年8月~2023年8月医院收治的157例骨质疏松症患者的一般资料及中医四诊资料进行回顾性分析,并统计骨质疏松症患者中医辨证分型结果,对不同症型患者基本资料、PINP、25-(OH)VitD_(3)、BMP-2水平进行比较。结果:157例骨质疏松症患者中医辨证分型属肾阳虚证34例,脾肾阳虚证43例,肝肾阴虚证49例,血瘀气滞证31例。不同中医辨证分型的骨质疏松患者血清PINP、25-(OH)VitD_(3)及BMP-2水平整体相比,差异有统计学意义(P<0.05);其中,血瘀气滞组PINP水平显著高于肾阳虚组、脾肾阳虚组及肝肾阴虚组患者(P<0.05),而其余3组两两间相比,差异无统计学意义(P>0.05);脾肾阳虚证患者25-(OH)VitD_(3)水平明显低于肾阳虚组、肝肾阴虚组及血瘀气滞组(P<0.05),且肾阳虚组低于肝肾阴虚组及血瘀气滞组(P<0.05),而其余两组相比差异无统计学意义(P>0.05);血瘀气滞组BMP-2水平显著低于肾阳虚组、脾肾阳虚组及肝肾阴虚组患者(P<0.05),而其余3组两两间相比,差异无统计学意义(P>0.05);二分类logistics回归分析结果显示,血瘀气滞与PINP呈正相关(P<0.05),与BMP-2呈负相关(P<0.05);脾肾阳虚与25-(OH)VitD_(3)呈负相关(P<0.05)。结论:骨质疏松症患者的血清PINP、25-(OH)VitD_(3)、BMP-2水平与其中医辨证分型具有一定相关性,可作为评估患者中医辨证分型的参考指标。

血清N-MID、TPINP与β-CTX水平检测在骨质疏松症中的临床意义

目的:探究血清骨钙素N端中分子片段(N-MID)、总I型胶原氨基端前肽(TPINP)、β胶原降解产物(β-CTX)水平检测在骨质疏松症(OP)中的临床意义。方法:选取120例OP患者为OP组;同期100名体检无OP者为对照组。比较两组对象血清N-MID、TPINP、β-CTX水平及腰椎L_(1~4)和股骨颈骨密度(BMD);Pearson相关性分析血清N-MID、TPINP、β-CTX水平与腰椎L_(1~4)和股骨颈骨BMD的关系;多因素Logistic回归分析影响OP发生的因素;受试者工作特征(ROC)曲线分析血清N-MID、TPINP、β-CTX水平对OP的诊断价值。结果:OP组患者血清N-MID、TPINP、β-CTX水平高于对照组(P<0.05);腰椎L_(1~4)及股骨颈BMD低于对照组(P<0.05)。相关性分析显示,血清N-MID、TPINP、β-CTX水平与腰椎L_(1~4)及股骨颈BMD均呈负相关关系(P<0.05)。回归分析显示,血清N-MID、TPINP、β-CTX、腰椎L_(1~4)及股骨颈BMD均为OP发生的独立影响因素(P<0.05)。ROC曲线分析显示,血清N-MID、TPINP、β-CTX诊断OP的最佳截断值分别为36.645、49.940、0.545 ng/mL;三项指标联合诊断OP的曲线下面积(AUC)为0.904,敏感度为90.80%,均高于单一指标诊断(P<0.05)。结论:与健康人群比较,OP患者血清N-MID、TPINP、β-CTX水平升高,且与患者BMD密切相关;血清N-MID、TPINP、β-CTX联合检查对OP有较高诊断价值。

50Hz正弦交变磁场对体外培养大鼠成骨细胞分化及BMP-2和collagen-I基因表达的影响

目的:研究频率为50 Hz不同强度正弦交变电磁场(electromagnetic fields,EMFs)对体外培养成骨细胞(Osteoblasts,OB)分化的影响。方法:体外分离培养大鼠颅骨成骨细胞,传代后随机分为9组,分别用频率50 Hz,磁场强度为0 mT(对照组)、0.9 mT、1.2 mT、1.5 mT、1.8 mT、2.1 mT、2.4 mT、2.7 mT和3.0 mT的正弦交变磁场处理,30 min/次/d。倒置相差显微镜下观察细胞形态;第3 d、6 d、9 d测定钙含量;第10 d茜素红钙化结节染色;RT-PCR法检测BMP-2和Collagen-I基因的表达。结果:磁场处理了3 d以后成骨细胞呈漩涡样分布;第9 d磁场组钙盐沉淀量普遍高于对照组,尤以1.8 mT显著高于对照(P<0.01)及其他各组(P<0.05);磁场处理组的BMP-2、Collagen-I基因表达水平高于对照组,其中1.8 mT和2.1 mT组表达量明显较高。结论:本实验所用50 Hz,0.9 mT^3.0 mT的正弦交变磁场能促进体外培养成骨细胞分化成熟,并提高BMP-2和Collagen-I的基因表达水平,其中以1.8 mT效果最为明显。

Targeting collagen expression in alcoholic liver disease

Alcoholic liver disease （ALD） is a leading cause of liver disease and liver-related deaths globally, particularly in developed nations. Liver fibrosis is a consequence of ALD and other chronic liver insults, which can progress to cirrhosis and hepatocellular carcinoma if left untreated. Liver fibrosis is characterized by accumulation of excess extracellular matrix components, including type I collagen, which disrupts liver microcirculation and leads to injury. To date, there is no therapy for the treatment of liver fibrosis; thus treatments that either prevent the accumulation of type I collagen or hasten its degradation are desirable. The focus of this review is to examine the regulation of type I collagen in fibrogenic cells of the liver and to discuss current advances in therapeutics to eliminate excessive collagen deposition.

Effect of magnesium ions/Type I collagen promote the biological behavior of osteoblasts and its mechanism

Type I collagen(Col I)is a main component of extracellular matrix(ECM).Its safety,biocompatibility,hydrophilicity and pyrogen immunogenicity make it suitable for tissues engineering applications.Mg2t also control a myriad of cellular processes,including the bone development by enhancing the attachment and differentiation of osteoblasts and accelerating mineralization to enhance bone healing.In our studies,Mg2t bind collagen to promote the proliferation and differentiation of osteoblasts through the expression of integrins and downstream signaling pathways.In order to clarify the biological behavior effect of 10mM Mg2t/Col I coating,we performed 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT),alkaline phosphatase(ALP),406-diamidino-2-phenylindole(DAPI),Alizarin red staining and Rhodamine B-isothiocyanate(RITC)-labeled phalloidin experiments and found that 10mM Mg2t group,Col I-coating group,10mM Mg2t/Col I-coating group,respectively,promoted the proliferation and differentiation of osteoblasts,especially 10mM Mg2t/Col I-coating group.We detected the mRNA expression of osteogenic-related genes(Runx2,ALP and OCN,OPN and BMP-2)and the protein expression of signaling pathway(integrin a2,integrin b1,FAK and ERK1/2),these results indicated that 10mM Mg2t/Col I coating play an critical role in up-regulating the MC3T3-E1 cells activity.The potential mechanisms of this specific performance may be through activating via integrin a2b1-FAK-ERK1/2 protein-coupled receptor pathway.

Is type Ⅰ alpha 2 collagen gene responsible for intracranial aneurysm in Northeast China?

In this study, we investigated whether a single nucleotide polymorphism （rs42524 G 〉 C） in the type I alpha 2 collagen gene was associated with sporadic ruptured intracranial aneurysm or its clinical characteristics in patients from Northeast China. Genotyping of the rs42524 G 〉 C polymorphism was carried out using a polymerase chain reaction-restriction fragment length polymorphism assay. The data showed that the frequency of the rs42524 GC ＋ CC genotype was significantly higher than the GG genotype among intracranial aneurysm patients whose Hunt and Hess grading scale was 〉 3. In addition, the rs42524 G 〉 C genotype was found to have a statistically significant association with intracranial aneurysm risk. These findings indicate that the type I alpha 2 collagen gene gene may be involved in a predisposition to intracranial aneurysm in the Northeast Chinese population. Crucially, the rs42524 C allele may be an important risk factor for increased severity of the condition in patients with ruptured intracranial aneurysms.

白细胞介素1β与机械牵拉共同作用角膜成纤维细胞CollagenⅠ及Lumican的表达

背景:继发性圆锥角膜是角膜屈光手术后的并发症之一,但其发生机制尚不清楚。目的:探讨白细胞介素1β与机械牵拉对角膜成纤维细胞CollagenⅠ和Lumican表达的影响。方法:体外培养角膜成纤维细胞,对其施加不同幅度(5%,10%,15%)的机械牵拉和不同质量浓度的白细胞介素1β,共同作用12,24,36 h,通过实时荧光定量PCR检测CollagenⅠ和Lumican m RNA的表达变化。结果与结论:(1)白细胞介素1β单独作用12 h使CollagenⅠα1的表达降低(P<0.05),作用24 h使Lumican的表达升高(P<0.05);(2)5%牵拉单独作用24,36 h使CollagenⅠα1表达升高(P<0.05);10%和15%牵拉单独作用12,24,36 h使CollagenⅠα1和CollagenⅠα2的表达降低(P<0.05);(3)5%牵拉单独作用12 h使Lumican表达升高(P<0.05),而10%和15%牵拉单独作用12 h使Lumican表达降低(P<0.05);5%,10%,15%牵拉24 h和36 h时使Lumican表达升高(P<0.05);(4)白细胞介素1β和机械牵拉共同作用24,36 h使CollagenⅠα1和CollagenⅠα2表达降低,Lumican表达升高;(5)结果提示,白细胞介素1β能抑制CollagenⅠ的合成,而促进Lumican的表达。低幅度机械牵拉能促进角膜成纤维细胞胶原的合成,中高幅度机械牵拉抑制其胶原的合成。两者共同作用能抑制角膜成纤维细胞胶原合成且促进Lumican的表达。

Fabrication and Properties of Poly(vinylalcohol)-glycosaminoglycantype I Collagen Composite Membrane as Tissue Regeneration Scaffolds

The objective of this paper is to design a based on composite membrane with certain mechanical porous polyvinyl alcohol （PVA） strength and biocompatibilities serving as tissue regenerative scaffolds. PVA-glycosaminoglycan （GAG）-type I collagen （COL） composite membrane was fabricated by PVA with different molecular weight （Mw） and alcoholysis degree （AD） being blended with certain amounts of GAG and COL and dried at 38~C for 24 h. The water content of the composite membranes were from 61.9% to 95.1% and swelling ratio ranged from 123.6% to 621.7%. Scanning electron micro- scope （SEM） analysis proved that PVA-GAG-COL composite membrane has porous and homogenous structure. Biocompatibility test results showed that the composite membrane was nontoxic, which could promote adhesion and proliferation of fibroblasts on the com- posite membrane. In conclusion, PVA-GAG-COL composite membrane with high water content and swelling ratio, suitable mechanical strength and good biocompatibility, has potential in tissue engineering and regenerative medicine.

Promotion of minTBP-1-PRGDN on the attachment,proliferation and collagen I synthesis of human keratocyte on titanium

AIM: To investigate the influence of minTBP-1-PRGDN on the attachment,proliferation and collagen I synthesis of human keratocyte on titanium(Ti) surface. · METHODS: The chimeric peptide RKLPDAPRGDN(minTBP-1-PRGDN) was synthesized by connecting RKLPDA(minTBP-1) to the N-terminal of PRGDN,the influence of minTBP-1-PRGDN on the attachment,proliferation and collagen I synthesis of human keratocyte on Ti surface were tested using PRGDN and minTBP-1 as controls. The keratocytes attached to the surface of Ti were either stained with FITC-labeled phalloidin and viewed with fluorescence microscope or quantified with alamar Blue method. The proliferation of keratocytes on Ti were quantified with 3-(4,5-dim-ethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide uptaking methods. The secretion of type I collagen was determined using an ELISA kit. ·RESULTS: The results showed that minTBP-1-PRGDN at a concentration of 100ng/mL was the most potent peptide to enhance the attachment of human keratocytes to the surface of Ti(1.40±0.03 folds,P =0.003),to promote the proliferation(1.26 ±0.05 folds,P =0.014) and the synthesis of type I collagen(1.530 ±0.128,P =0.008). MinTBP-1 at the same concentration could only promote the attachment(1.13±0.04 folds,P =0.020) and proliferation(1.15±0.06 folds,P =0.021),while PRGDN had no significant influence(P 】0.05). ·CONCLUSION: Our data show that the novel chimericpeptide minTBP-1-PRGDN could promote the attachment,proliferation and type I collagen synthesis of human keratocytes on the surface of titanium.

Efficient induction of neural progenitor cells from human ESC/iPSCs on Type I Collagen

A stable,rapid and effective neural differentiation method is essential for the clinical applications of human embryonic stem cells(ESCs)or induced pluripotent stem cells(iPSCs)in treating neurological disorders and diseases.Herein,we established a novel and robust monolayer differentiation method to produce functional neural progenitor cells(NPCs)from human ESC/iPSCs on Type I Collagen.The derived cells not only displayed the requisite markers,but also behaved similarly to classic NPCs both in vitro and in vivo.Upon transplantation into traumatic brain injury model,the derived NPCs facilitated recovery from injury.We also found that SMAD signaling stayed down throughout the differentiation process on Type I Collagen,and the pluripotent signals were rapidly downregulated along with raising up of neural early markers on the third day.Meanwhile,ATAC-seq data showed the related mediation of distinct transcriptome and global chromatin dynamics during NPC induction.Totally,our results thus provide a convenient way to generate NPCs from human ESC/iPSCs for neural diseases’treatment.

Association of bone turnover biomarkers with severe intracranial and extracranial artery stenosis in type 2 diabetes mellitus patients

BACKGROUND Intracranial and extracranial artery stenosis is associated with cerebral infarction.Vascular calcification and atherosclerosis are the main causes of stenosis and major risk factors for cardiovascular and cerebrovascular events in patients with type 2 diabetes mellitus(T2DM).Bone turnover biomarkers(BTMs)are associated with vascular calcification,atherosclerosis,glucose,and lipid metabolism.AIM To investigate the association of circulating BTM levels with severe intracranial and extracranial artery stenosis in patients with T2DM.METHODS For this cross-sectional study including 257 T2DM patients,levels of the BTMs serum osteocalcin(OC),C-terminal cross-linked telopeptide of type I collagen(CTX),and procollagen type I N-peptide were measured by electrical chemiluminescent immunoassay,and artery stenosis was assessed by color Doppler and transcranial Doppler.Patients were grouped according to the existence and location(intracranial vs.extracranial)of artery stenosis.Correlations between BTM levels,previous stroke,stenosis location,and glucose and lipid metabolism were analyzed.RESULTS T2DM patients with severe artery stenosis had a higher frequency of previous stroke and levels of all three tested BTMs(all P<0.05)than patients without.Some differences in OC and CTX levels were observed according to the location of artery stenosis.Significant associations were also observed between BTM levels and some glucose and lipid homeostasis parameters.On multivariate logistic regression analysis,all BTMs were significant predictors of artery stenosis in T2DM patients with and without adjustment for confounding factors(all P<0.001),and receiver operating characteristic curve analysis demonstrated the ability of BTM levels to predict artery stenosis in T2DM patients.CONCLUSION BTM levels were found to be independent risk factors for severe intracranial and extracranial artery stenosis and were differentially associated with glucose and lipid metabolism in patients with T2DM.Therefore,BTMs may be promising biomarkers and potential therapeutic targets for artery stenosis.

PI3K/CTGF信号通路在TGF-β1诱导A549细胞表达collagen Ⅰ过程中的作用

目的:研究磷脂酰肌醇3-激酶/结缔组织生长因子(PI3K/CTGF)信号通路在转化生长因子β1(TGF-β1)诱导人肺腺癌A549细胞表达I型胶原蛋白(collagen I)过程中的分子机制。方法:体外培养A549细胞,予TGF-β1刺激,观察CTGF和collagen I的mRNA和蛋白表达及PI3K信号通路的活化;PI3K抑制剂LY294002预先处理A549细胞后,观察TGF-β1刺激下CTGF和collagen I mRNA和蛋白表达的变化;CTGF特异性si RNA干扰A549细胞中CTGF的表达后,观察TGF-β1刺激下collagen I mRNA和蛋白表达的变化和PI3K信号通路的活化。结果:TGF-β1可以诱导A549细胞中CTGF和collagen I的mRNA和蛋白表达以及PI3K信号通路的活化;PI3K特异性抑制剂LY294002可以部分逆转TGF-β1诱导的A549细胞中CTGF和Collagen I mRNA和蛋白表达的升高。干扰CTGF可以降低TGF-β1诱导的A549细胞collagen I mRNA和蛋白表达,而不影响PI3K信号通路的活化。结论:CTGF是TGF-β1/PI3K信号通路调控的即刻早期反应效应蛋白,参与了TGF-β1诱导的A549细胞中collagen I表达。

rhPTH_((1-34))对成骨细胞增殖、CollagenⅠ及Osterix mRNA表达的影响

目的观察间歇给予重组人甲状旁腺激素(1-34)[rhPTH(1-34)]对体外成骨细胞增殖、Ⅰ型胶原蛋白(Collagen Ⅰ)及Osterix mRNA表达的影响,初步探讨rhPTH(1-34)对体外成骨细胞的作用机制。方法体外培养新生大鼠成骨细胞,间歇循环给予0、10-11、10-10、10-9、10-8、10-7M rhPTH(1-34)干预,(24 h为一循环,前12h给药),共2次,用MTT法检测细胞的增殖;RT-PCR法半定量测定成骨细胞Collagen Ⅰ、Osterix mRNA的表达。结果显示rhPTH(1-34)可明显促进成骨细胞的增殖(P<0.05),促进成骨细胞Collagen Ⅰ和Osterix mRNA表达(P<0.05),10-9 M增殖、表达最明显,呈剂量依赖关系。结论 rhPTH(1-34)可促进成骨细胞的增殖、分化,可能是通过Collagen Ⅰ和Osterix mRNA表达来调节。

Preparation and Characterisation of Collagen from Freshwater Fish Scales

Acid-soluble collagen (ASC) and pepsin-solubilized collagen (PSC) were prepared from the waste freshwater carp fish scales. The results of SDS-PAGE showed that purified collagens were composed of at least two different chains which were in accordance with the type I collagen with α chain composition of (α1)2α2. Compared with the carp fish ordinary muscle type I collagen , porcine dermis type I collagen and other seawater fish collagens, freshwater carp fish scales collagen contained relative high half-cystine (Cys-s), but lower denaturation temperature(Td) than the porcine dermis type I collagen. These collagens had evident absorption at 230 nm by UV-Vis spectra. The spectrum X-ray diffraction showed that the collagen remained single-helix and tri-helix configuration with the minimum values of the repeat spacings (d) of about 4.48 ? and 11.87 ?. Therefore, to make more effective use of limited-resources, carp fish scales can be a potential resource for the extraction of type I collagen or gelatin.

Fabrication of Novel Scaffolds Containing Collagen-I/Polylactic Acid/Nanohydroxyapatite via Co-electrospinning Methods

A novel scaffold containing collagen-I/polylactic acid（PLA）/nanohydroxyapatite（nHA） was prepared via co-electrospinning method. Different target substrates were used to improve the collection efficiency of this scaffold. The properties of the novel scaffold were compared with those of conventionally prepared ones. Compared to con- ventional method, the modified method was more efficient in producing the scaffold. Moreover, the porosity, thickness, and morphology of the novel scaffold were better than those of scaffolds prepared by conventional methods. The properties of collagen-I, collagen-I/PLA and collagen-I/PLA/nHA scaffolds were also compared. Diameters of the electrospun fibers ranged from 180 to 405 nm, and roughness was present on the surface of the fibers due to the deposition of crystals of nHA along the long axis of the fibers. The fibers of the collagen-I/PLA/nHA scaffold and the fibers of natural bone tissue had similar structure.

Novel electrospun poly(ε-caprolactone)/type Ⅰ collagen nanofiber conduits for repair of peripheral nerve injury

Recent studies have shown the potential of artificially synthesized conduits in the repair of peripheral nerve injury. Natural biopolymers have received much attention because of their biocompatibility. To investigate the effects of novel electrospun absorbable poly(ε-caprolactone)/type Ⅰ collagen nanofiber conduits(biopolymer nanofiber conduits) on the repair of peripheral nerve injury, we bridged 10-mm-long sciatic nerve defects with electrospun absorbable biopolymer nanofiber conduits, poly(ε-caprolactone) or silicone conduits in Sprague-Dawley rats. Rat neurologica1 function was weekly evaluated using sciatic function index within8 weeks after repair. Eight weeks after repair, sciatic nerve myelin sheaths and axon morphology were observed by osmium tetroxide staining, hematoxylin-eosin staining, and transmission electron microscopy.S-100(Schwann cell marker) and CD4(inflammatory marker) immunoreactivities in sciatic nerve were detected by immunohistochemistry. In rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits, no serious inflammatory reactions were observed in rat hind limbs, the morphology of myelin sheaths in the injured sciatic nerve was close to normal. CD4 immunoreactivity was obviously weaker in rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits than in those subjected to repair with poly(ε-caprolactone) or silicone. Rats subjected to repair with electrospun absorbable biopolymer nanofiber conduits tended to have greater sciatic nerve function recovery than those receiving poly(ε-caprolactone) or silicone repair. These results suggest that electrospun absorbable poly(ε-caprolactone)/type Ⅰ collagen nanofiber conduits have the potential of repairing sciatic nerve defects and exhibit good biocompatibility. All experimental procedures were approved by Institutional Animal Care and Use Committee of Taichung Veteran General Hospital, Taiwan, China(La-1031218) on October 2, 2014.

Modified insulin-like growth factor 1 containing collagen-binding domain for nerve regeneration

Insulin-like growth factor 1 （IGF-I） is a potential nutrient for nerve repair. However, it is impractical as a therapy because of its limited half- life, rapid clearance, and limited target specificity. To achieve targeted and long-lasting treatment, we investigated the addition of a binding structure by fusing a collagen-binding domain to IGF- 1. After confirming its affinity for collagen, the biological activity of this construct was examined by measuring cell proliferation after transfection into PC12 and Schwann cells using a 3-（4,5-dimethyl-2-thiazolyl）-2,5-di- phenyl-2-H-tetrazolium bromide assay. Immunofluorescence staining was conducted to detect neurofilament and microtubule-associated protein 2 expression, while real time-polymerase chain reaction was utilized to determine IGF-1 receptor and nerve growth/actor mRNA expression. Our results demonstrate a significant increase in collagen-binding activity of the recombinant protein compared with IGF-1. Moreover, the recombinant protein promoted proliferation of PC12 and Schwann cells, and increased the expression of neurofilament and microtubule-associated protein 2. Importantly, the recombinant protein also stimulated sustained expression of IGF-1 receptor and nerve growth factor mRNA for days. These results show that the recombinant protein achieved the goal of targeting and long-lasting treatment, and thus could become a clinically used factor for promoting nerve regeneration with a prolonged therapeutic effect.