Comparative Investigation on the Phytochemicals and Biological Activities of Jackfruit (Artocarpus heterophyllus Lam.) pulp from Five Cultivars.

Jackfruit is one of the major tropical fruits, but information on the phytochemicals and biological benefits of its pulp is limited. In this study, the phytochemicals and biological activities including antioxidant, antitumor and anti-inflammatory activities of five jackfruit pulp cultivars (M1, M2, M3, M7 and T5) were comparatively investigated. A total of 11 compounds were identified in all cultivars of jackfruit pulp, among which 4-hydroxybenzoic acid, caffeic acid, ferulic acid and tryptophan N-glucoside were reported for the first time in jackfruit. T5 exhibited the highest total phenolic content (7.69 ± 0.73 mg GAE/g DW), antioxidant capacity (109.8, 96.7 and 207 mg VCE/g DW for DPPH, ABTS and FRAP, respectively), antitumor activity (80.31%) and anti-inflammatory activity (78.44%) among five cultivars. These results can provide a reference for growers to choose jackfruit cultivar and offer an insight into the industrial application of jackfruit pulp derived-products.

Genome-wide DNA polymorphism in the indica rice varieties RGD-7S and Taifeng B as revealed by whole genome re-sequencing.

Next-generation sequencing technologies provide opportunities to further understand genetic variation, even within closely related cultivars. We performed whole genome resequencing of two elite indica rice varieties, RGD-7S and Taifeng B, whose F1 progeny showed hybrid weakness and hybrid vigor when grown in the early- and late-cropping seasons, respectively. Approximately 150 million 100-bp pair-end reads were generated, which covered ∼86% of the rice (Oryza sativa L. japonica 'Nipponbare') reference genome. A total of 2,758,740 polymorphic sites including 2,408,845 SNPs and 349,895 InDels were detected in RGD-7S and Taifeng B, respectively. Applying stringent parameters, we identified 961,791 SNPs and 46,640 InDels between RGD-7S and Taifeng B (RGD-7S/Taifeng B). The density of DNA polymorphisms was 256.8 SNPs and 12.5 InDels per 100 kb for RGD-7S/Taifeng B. Copy number variations (CNVs) were also investigated. In RGD-7S, 1989 of 2727 CNVs were overlapped in 218 genes, and 1231 of 2010 CNVs were annotated in 175 genes in Taifeng B. In addition, we verified a subset of InDels in the interval of hybrid weakness genes, Hw3 and Hw4, and obtained some polymorphic InDel markers, which will provide a sound foundation for cloning hybrid weakness genes. Analysis of genomic variations will also contribute to understanding the genetic basis of hybrid weakness and heterosis.

Bacillus vanillea sp. nov., Isolated from the Cured Vanilla Bean.

A Gram-positive bacterium, designated strain XY18(T), was isolated from a cured vanilla bean in Hainan province, China. Cells were rod-shaped, endospore producing, and peritrichous flagella. Strain XY18(T) grew at salinities of 0-8 % (w/v) NaCl (optimally 1-4 %), pH 4.0-8.0 (optimally 5.0-7.0 %) and temperature range 20-45 °C (optimally 28-35 °C). The predominant menaquinone was MK-7. The major cellular fatty acids were anteiso-C15:0, iso-C15:0, anteiso-C17:0, and iso-C17:0. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain XY18(T) was a member of the genus Bacillus, and closely related to B. amyloliquefaciens NBRC 15535(T) and B. siamensis PD-A10(T), with 99.1 and 99.2 % sequence similarity, respectively. However, the DNA-DNA hybridization value between strain XY18(T) and B. amyloliquefaciens NBRC 15535(T) was 35.7 %. The genomic DNA G+C content of strain XY18(T) was 46.4 mol%, significantly differed from B. siamensis PD-A10(T) (41.4 %), which was higher than the range of 4 % indicative of species. On the basis of polyphasic taxonomic study, including phenotypic features, chemotaxonomy, and phylogenetic analyses, strain XY18(T) represents a novel species within the genus Bacillus, for which the name Bacillus vanillea sp. nov. is proposed. The type strain is XY18(T) (=CGMCC 8629 = NCCB 100507).

Role of Stromal Cell-Derived Factor-1 in Endothelial Progenitor Cell-Mediated Vascular Repair and Regeneration.

Endothelial progenitor cells (EPCs) are immature endothelial cells that participate in vascular repair and postnatal neovascularization and provide a novel and promising therapy for the treatment of vascular disease. Studies in different animal models have shown that EPC mobilization through pharmacological agents and autologous EPC transplantation contribute to restoring blood supply and tissue regeneration after ischemic injury. However, these effects of the progenitor cells in clinical studies exhibit mixed results. The therapeutic efficacy of EPCs is closely associated with the number of the progenitor cells recruited into ischemic regions and their functional abilities and survival in injury tissues. In this review, we discussed the regulating role of stromal cell-derived factor-1 (also known CXCL12, SDF-1) in EPC mobilization, recruitment, homing, vascular repair and neovascularization, and analyzed the underlying machemisms of these functions. Application of SDF-1 to improve the regenerative function of EPCs following vascular injury was also discussed. SDF-1 plays a crucial role in mobilizing EPC from bone marrow into peripheral circulation, recruiting the progenitor cells to target tissue and protecting against cell death under pathological conditions; thus improve EPC regenerative capacity. SDF-1 are crucial for regulating EPC regenerative function, and provide a potential target for improve therapeutic efficacy of the progenitor cells in treatment of vascular disease.

Simultaneously constructing nanotopographical and chemical cues in 3D-printed polylactic acid scaffolds to promote bone regeneration.

Topographical structures and bioactive surface coatings are effective in improving the biological function for bone regeneration. However, the simultaneous introduction of these benefits into three-dimensional (3D) porous scaffolds poses a daunting challenge. In this study, we proposed a simple yet effective approach to decorate 3D-printed polylactic acid (PLA) scaffolds with chemically modified nanotopographical patterns. The nanotopography was produced by etching the amorphous phase of PLA in an alcohol/alkali solution to expose dense lamellae. Subsequently, conformal decoration of polydopamine (PDA) was realized via self-assembly of catecholamines without changing the surface nanotopography. In vitro cell experiments including live and dead staining, cell morphology, cell growth, and alkaline phosphatase showed that the combination of nanotopography and PDA-coating led to a favorable enhancement of osteoblasts adhesion, spread and proliferation in 3D-printed scaffolds. The contribution of integrated patterns to bone regeneration was evaluated using a rat femur critical-sized defect model in vivo. Micro-CT evaluation and histological analysis demonstrated that the scaffold decorated with integrated pattens promoted osteogenesis more than the bare scaffolds and the scaffolds decorated with only nanotopography. Our proposed approach offers a promising method for improving bioactivity of 3D polymer scaffolds for bone tissue regeneration.

[Analysis of soluble Ca content in banana pulp based on pretreatment of digestion model in vitro].

In the present paper, soluble Ca content in banana pulp was analyzed with pretreatment of digestion model in vitro. All the samples were digested by strong acid (perchloric acid and nitric acid with 1 : 4 ratio) and determined by AA700 flame atomic absorption spectrophotometry (FAAS). Meanwhile, the reproducibility of the analytical method was investigated. The results showed that (1) Content of Ca was 1.479 mg x g(-1) x DW in eighty percent maturity banana pulp. And the relative standard deviation was 4.12%. (2) Contents of Ca in the soluble and insoluble fractions were 1.108 and 0.412 mg x g(-1) x DW, respectively in eighty percent maturity banana pulp with pretreatment of digestion model in vitro. The extraction rate was 74.9% and the residue rate was 27.8%. (3) The relative standard deviations of the analytical results of Ca contents in those two fractions were 2.56% and 9.10%, respectively, in the reproducibility tests. It was showed that the digestion model in vitro did not affect the reproduction quality significantly. Moreover, the deviation between the theoretical value and the summation value of the extraction and the residue rates was only 2.7%, which showed good availability of the digestion model in vitro to be used as a pretreatment method in mineral element analysis process. (4) Relative standard deviation and recovery yield in the determination procedure were 0.11% (n = 9) and 99.2%, respectively.

[Analysis of primary elemental speciation distribution in mungbean during enzymatic hydrolization].

In the present paper, trace elements contents of cuprum, zincum, manganese and ferrum in mungbean and their primary speciation distribution during enzymatic hydrolization were investigated with ICP-AES OPTIMA 5300DV plasma emission spectroscopy. The trace elements were separated into two forms, i.e. dissolvable form and particulate form, by cellulose membrane with 0.45 microm of pore diameter. All the samples were digested by strong acid (perchloric acid and nitric acid with 1 : 4 ratio ). The parameters of primary speciations of the four elements were calculated and discussed. The results showed: (1) Contents of cuprum, zincum, manganese and ferrum in mungbean were 12.77, 31.26, 18.14 and 69.38 microg x g(-1) (of dry matter), respectively. Different treatment resulted in different elemental formulation in product, indicating that more attention should be paid to the trace elements pattern when producing mungbean beverage with different processes. (2) Extraction rates of cuprum, zincum, manganese and ferrum in extract were 68.84%, 51.84%, 63.97% and 30.40% with enzymatic treatments and 36.22%, 17.58%, 7.85% and 22.99% with boil treatment, respectively. Both boil and enzymatic treatments led to poor elemental extraction rates, which proved that it was necessary to take deep enzymatic hydrolysis treatment in mungbean beverage process as the trace element utilization rate was concerned. (3) Amylase, protease and cellulose showed different extraction effectiveness of the four trace elements. Generally, protease exhibited highest efficiency for the four elements extraction. All of the four trace elements were mostly in dissolvable form in all hydrolysates and soup. (4) Relative standard deviations and recovery yields are within 0.12%-0.90% (n = 11) and 98.6%-101.4%, respectively. The analysis method in this paper proved to be accurate.

Role of HA and BG in engineering poly(ε-caprolactone) porous scaffolds for accelerating cranial bone regeneration.

Effects of varied bioactive fillers on the biological behavior of porous polymer/inorganic composite scaffolds are lack of comprehensive comparison and remain elusive. Moreover, composite scaffolds with high porosity suffer from inferior mechanical performance. Herein, high-pressure molding and salt leaching were employed to prepare poly(ε-caprolactone) (PCL) composite porous scaffolds loaded with hydroxyapatite (HA) and bioactive glass (BG), respectively. Structural analysis indicated all the porous scaffolds presented interconnected open-pore structure with the porosity of ~87% and pore size of ~180 µm, hinging on the amounts and size of porogen. Compared to PCL/HA scaffolds, PCL/BG scaffolds showed ~2.3-fold augment in the water absorption. Attributing to the compact framework, the PCL/HA and PCL/BG porous scaffolds exhibited outstanding compressive modulus, which was notably higher than other PCL composite porous scaffolds reported in literatures. Cells culture results demonstrated that PCL/BG scaffolds displayed higher expression of osteogenic differentiation than PCL and PCL/HA scaffolds. Furthermore, in vivo results showed that more mature bone was formed within PCL/BG scaffolds than PCL/HA scaffolds, manifesting that the introduction of BG accelerated cranial bone regeneration to obtain complete bone healing within a short time. Therefore, these data indicate that PCL/BG scaffolds are more competitive for bone tissue engineering application. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 654-662, 2019.

Accelerating Bone Healing by Decorating BMP-2 on Porous Composite Scaffolds.

Although artificial polymeric scaffolds act as vital characters in bone repair, their application is limited due to their inferior bioactivity. Herein, osteoinductive poly(ε-caprolactone) (PCL) composite scaffolds were prepared by synchronously enlisting bioactive nanohydroxyapatite (nHA), bioglass (BG), and bone morphogenetic protein-2 (BMP-2), which was bound up with polydopamine (pDA). It was found that pDA deposition not only significantly enhanced hydrophilicity and cell affinity of composite scaffolds but also endowed steady immobilization of BMP-2 with long-term yet sustained release. Compared to pure PCL and PCL/nHA/BG (PHB) scaffolds, the designed PHB-pDA-BMP-2 scaffolds significantly induced the differentiation of bone marrow stromal cells toward an osteogenic lineage. Meanwhile, in vivo examinations revealed the prominent osteogenic capability of PHB-pDA-BMP-2 scaffolds, which enabled complete bone healing of calvarial bone defects in rabbits by 12 weeks. This finding indicates that the developed porous composite scaffolds hold great potential for bone regeneration.

[Analysis of speciation distribution of se in mungbean during enzymatic hydrolization].

In the present paper, selenium content in mungbean and selenium speciation distribution in mungbean during enzymatic hydrolization was investigated with AFS-230E atomic fluorescence photometer. Selenium in the decoction and enzymatic hydrolysates samples were separated into two species including primary speciation and secondary speciation. The primary speciation included the soluble and the suspended forms and was divided by 0.45 microm filter membrane. The secondary speciation included the inorganic and the organic forms and was divided by D101 macroreticular resin. The speciation parameters of selenium such as extractive rate, remain rate, residue rate, immerse-residue ratio and speciation distribution coefficients, etc in different samples were calculated. The results showed: (1) Selenium content in mungbean was 54.79 microg x g(-1) (of dry matter). (2) Over 90% selenium in mungbean was extracted by enzymatic treatment, but only 19.26% selenium came out in water when only treated by hot water. The extraction rates of Se in the process of amylase, protease and cellulase were 33. 64%, 55.96% and 5.189%, respectively. It was inferred that most selenium was in conjugate or complexation form in mungbean protein. (3) The distribution coefficient of selenium in organic form was 59.87% in the total enzymatic product and 3.64% in the mungbean soup. Organic form distribution coefficients of selenium in amylase and protease hydrolysates were 15.51% and 44.36%, respectively. No organic selenium was detected in cellulase hydrolysate. It was inferred that selenium was in complexation form in mungbean cellulose. All the results showed that enzymatic hydrolization treatment did not only improve the total content of selenium greatly, but also materially improved the organic form content of selenium in water. The recovery for the method was 97.8% and RSD was 1.1% (n=11).

Advanced technology for nanostarches preparation by high speed jet and its mechanism analysis.

Nanostarches were successfully prepared by high speed jet (HSJ) after pretreatment of micronization. The nanostarches were obtained at the conditions of micronization treatment for 60min, and then one cycle at 240MPa of HSJ (188.1nm). Moreover, after HSJ treated for three cycles, the particle size could reach the level of nanometer materials (66.94nm). The physicochemical properties of nanostarches had been characterized. Rapid Visco-Analysis (RVA) showed that the viscosity of nanostarches significantly decreased compared with native tapioca starch and slightly decreased with increasing processing cycles of HSJ. Steady shear analysis indicated that all samples displayed pseudoplastic, shear-thinning behavior, while the flow curves of nanostarches were little impact by the processing cycles of HSJ. X-ray diffraction analysis showed that the complete destruction of tapioca starch crystalline structure was obtained after HSJ treatment. Molecular characteristics determination suggested that the degradation of amylopectin chains occurred after the treatment of micronization and HSJ, which was proved by the decrease of weight-average molar mass. The results demonstrated that nanostarches were obtained due to the breakdown of starch molecules. This study will provide useful information of the nanostarches for its potential industrial application.

[Species of Iron in Size-resolved Particle Emitted from Xuanwei Coal Combustion and Their Oxidative Potential].

Many reports have claimed that high lung cancer mortality rate in Xuanwei is associated with the residential coal combustion. Considering iron is the main chemical element in the particles emitted from Xuanwei coal combustion, and especially, reactive oxygen species (ROS) could be generated by redox-active transition metals (TM) such as iron (Fe) in particles, therefore, raw coal samples from 4 coal mines in Xuanwei were sampled, and size-resolved particles emitted from the raw coal samples were collected by using of Andersen Five-stage High Volume Sampler. Species of iron in the raw coal sample, size-resolved particles and bottom ashes were analyzed by BCR sequential extraction method (community bureau of reference, BCR). The generation potential of·OH free radicals from coal emission particles in the surrogate lung fluid (SLF) solution was measured by using high pressure liquid chromatography (HPLC). Our results demonstrated that a large fraction of oxidizable Fe could be found in raw coal samples. However, the acid extractable, reducible and oxidizable fractions of Fe in the fly ash particles accounted for a large proportion (46%-78%) in the size-resolved particles after coal combustion. There was difference in levels of·OH free radicals generated from coal emission particles in the SLF for 24 hours among particles with different sizes. The concentration of·OH increased in both fine particles (<1 µm, 1.1-2 µm, 2-3.3 µm) and coarse particles (3.3-7 µm, >7 µm) as the particles size decreased. Linear correlation could be found between the oxidizable fractions of iron and the generation of·OH in particles emitted from coal combustion (R2=0.32).

Surgical repair of hard palate cleft with absorbable membrane: the new surgical technique and its clinical application.

This study evaluated a new surgical technique with absorbable membrane to repair hard palate cleft without extensive mobilisation of the mucoperiosteum. From 2001 to 2002, 32 selected patients with complete unilateral clefts underwent this surgical operation. The traditional flap surgical operation was performed at the soft palate, uvula and anterior alveolar cleft. The absorbable membrane was implanted to the hard palate cleft gap to guide the regeneration of the mucoperiosteum. The patients were followed up for 1-6 months after the operation. The speech assessment was carried out 12 months after the operation. Of 32 patients, 30 were successfully operated by this method and no obvious complications occurred. Primary healing on tissue defect of hard palate was obtained in 27 patients and secondary healing in 3 patients. Eighty percent of the 30 patients had good or excellent speech 12 months after the operation. The operation failed in 2 patients. The surgical technique with absorbable membrane to repair hard palate appears to have several valuable advantages including the decreased area of the hard palate involved and favourable outcome for speech in the majority of cases.

Atorvastatin protects endothelial colony­forming cells against H2O2­induced oxidative damage by regulating the expression of annexin A2.

Endothelial dysfunction and injury are central events in the pathogenesis of ischemic vascular disorders. Endothelial progenitor cells (EPCs) are mobilized from the bone marrow into the peripheral circulation, where they locate to sites of injured endothelium and are involved in endothelial repair and vascular regeneration. During these processes, EPCs are exposed to oxidative stress, a crucial pathological condition, which occurs during vascular injury and limits the efficacy of EPCs in the repair of injured endothelium. Statins are effective inhibitors of 3­hydroxy­3­methylglutaryl coenzyme A reductase, and are commonly used to manage and prevent ischemic vascular disease by reducing plasma cholesterol levels. In addition to lowering cholesterol, statins have also been reported to exert pleiotropic actions, including anti­inflammatory and anti­oxidative activities. The present study aimed to investigate the ability of atorvastatin to protect endothelial colony­forming cells (ECFCs), a homogeneous subtype of EPCs, from hydrogen peroxide (H2O2)­induced oxidative damage, and to determine the mechanism underlying this protective action. MTT assay, acridine orange/ethidium bromide staining, reactive oxygen species assay, western blot analysis and tube formation assay were employed. The results demonstrated that H2O2 induced cell death and decreased the tube­forming ability of the ECFCs, in a concentration­dependent manner; however, these effects were partially attenuated following administration of atorvastatin. The reversion of the quantitative and qualitative impairment of the H2O2­treated ECFCs appeared to be mediated by the regulation of annexin A2, as the expression levels of annexin A2 were decreased following treatment with H2O2 and increased following treatment with atorvastatin. These results indicated that annexin A2 may be involved in the H2O2­induced damage of ECFCs, and in the protective activities of atorvastatin in response to oxidative stress.

Effect of nerve growth factor and Schwann cells on axon regeneration of distracted inferior alveolar nerve following mandibular lengthening.

OBJECTIVE: To study the effect of nerve growth factor (NGF) and Schwann cells on axon regeneration of the inferior alveolar nerve following mandibular lengthening with distraction osteogenesis. METHODS: Unilateral mandibular osteodistraction was performed in 9 healthy adult male goats with a distraction rate of 1 mm/d. Every 3 goats were killed on days 7, 14 and 28 after mandibular lengthening, respectively. The inferior alveolar nerves in the distraction callus were harvested and processed for ultrastructural and NGF immunohistochemical study. The inferior alveolar nerves from the contralateral side were used as controls. RESULTS: On day 7 after distraction, axon degeneration and Schwann cell proliferation were observed, and very strong staining of NGF in the distracted nerve was detected. On day 14 after distraction, axon regeneration and remyelination were easily observed, and NGF expression started to decline. On day 28 after distraction, the gray scale of NGF immunoreactivity recovered to the normal value and the Schwann cells almost recovered to their normal state. CONCLUSIONS: Gradual mandibular osteodistraction can result in mild or moderate axon degeneration of the inferior alveolar nerve. Nerve trauma may stimulate the proliferation of Schwann cells and promote the synthesis and secretion of NGF in the Schwann cells. Schwann cells and NGF might play important roles in axon regeneration of the injured inferior alveolar nerve following mandibular lengthening.

Correction of mandibular deficiency by inverted-L osteotomy of ramus and iliac crest bone grafting.

This study was to describe the use of inverted-L osteotomy of ramus and iliac bone graft for the management of mandibular deficiency in adult patients. From 2008 to 2010, 11 patients (aged 19 to 29 years) with mandibular deficiency underwent intraoral or extraoral inverted-L osteotomy of ramus and iliac crest bone grafting. Data were collected from the patients' records, photographs and radiographs. The height and width of the ramus were successfully expanded by inverted-L osteotomy and iliac crest bone grafting with minimal complications in all patients, resulting in significant improvement in occlusion and facial appearance. Our early results showed that the inverted-L osteotomy of ramus and iliac crest bone grafting is safe and effective, and should be considered as a good alternative for the patients with mandibular deficiency.

Effect of C/N ratios on the performance of earthworm eco-filter for treatment of synthetics domestic sewage.

PURPOSE: The performances of filter systems that use earthworms and plants, combined with earthworm eco-filter (EE) systems in treating synthetic domestic sewage (SDS) with different C/N ratios, were investigated for a 9-month period. METHODS: The effects of the combination of filters, earthworms, plants, as well as the combination of earthworms and plants on SDS nutrient removal efficiency were separately investigated to select the optimum system for treating SDS. The results of the current study could be used to determine how treatment performance responds to different C/N ratios and to explain and predict the performance of an operating EE system. RESULTS: EE systems with earthworms and plants (EP groups) consistently performed better than the other types of systems (CK, E, and P; that is, without earthworms and without plants, with earthworms and without plants, and without earthworms and with plants, respectively) under all C/N ratios. The highest removal efficiencies of chemical oxygen demand, total nitrogen, total phosphorus, and total organic carbon were achieved under C/N ratios of 6:1, 6:1, 6:1, and 9:1, respectively. The optimum nutrient removal efficiency was achieved at C/N = 6, and the contribution order for nutrient removal was EP > P > E > CK. CONCLUSIONS: Influent C/N ratios, the time of year, and the synergetic effects of earthworm behavior and microorganisms significantly affected nutrient removal efficiencies. Considering the removal of all nutrients, EE systems with plants and earthworms achieved optimum removal effects in July when the influent C/N ratio was controlled at 6. Appropriate control of carbon and nitrogen source concentrations permitted the achievement of optimal nutrient removal effects.

[Narrowing and sliding genioplasty procedure combined with mandibular outer cortex ostectomy technique to correct square jaw in short face].

OBJECTIVE: To evaluate the the feasibility and effectiveness of narrowing and sliding genioplasty combined with mandibular outer cortex ostectomy technique to reshape a square jaw in short face. METHODS: From July 2005 to October 2009, a total of 57 patients received narrowing and sliding genioplasty combined with mandibular outer cortex ostectomy procedure to correct square jaw in short face. All the patients had standard frontal and lateral cephalometric radiographs, panoramic radiographs, and were photographed preoperatively and postoperatively to assess their face contour. The alteration of mandibular angle, mental contour and width of lower face was observed for 6 to 24 months postoperatively. Questionnaires were used to assess the patients' satisfactory. RESULTS: It showed that the postoperative lower face had narrowed and become softer, slender and oval, with a slick mental region. The final aesthetic outcomes were quite satisfactory in all cases from both the view of surgeons and patients. CONCLUSIONS: Narrowing and sliding genioplasty combined with mandibular outer cortex ostectomy procedure could efficiently adjust the shape and position of chin to obtain a good proportion of the lower face, and to change square and short face to slender oval one by single operation in accordance with the fashionable aesthetics in orientals.

[Reconstruction of critical sized calvarial defects by porous nano-hydroxyapatite/polyamide 6 composite with bone marrow mesenchymal stem cells in rat].

OBJECTIVE: To evaluate the effects of the nano-hydroxyapatite/polyamide 6 (n-HA/PA6) on the proliferation and osteoblastic differentiation of rat bone marrow mesenchymal stem cells (BMSCs), and the feasibility of using both for constructing tissue engineered bone in the calvarias of rats with critical sized defects. METHODS: The third passage of BMSCs were cultured in osteoblastic medium and seeded on the scaffolds of n-HA/PA6, the proliferation of the BMSCs was tested by MTT (3-{4,5-dimethylthiazol-2yl}-2,5-diphenyl-2H-tetrazolium-bromide) on scheduled dates, and the osteoblastic differentiation of the BMSCs were measured by alkaline phosphatase (ALP) staining. Furthermore, the scaffolds with or without BMSCs in rat calvarial defects, after 4 weeks, 8 weeks, and 16 weeks have been implanted. Histology and scanning electron microscope were used to test the bone healing in the different groups. RESULTS: The BMSCs seeded on the n-HA/PA6 grew well, the proliferation of cells was not affected by the scaffold, and the staining of ALP was also positive. At 4 week and 8 week after implantation, the n-HA/PA6 with BMSCs showed more new bone formation on the surface of scaffolds, with a better osseointegration of implant and host bone when compared with the group of n-HA/PA6 without BMSCs. However, there was no significant difference between these two groups at 16 week. CONCLUSION: The porous n-HA/PA6 has no negative effects on the proliferation and osteoblastic differentiation of rat BMSCs, and using BMSCs as seed cells and n-HA/PA6 as scaffolds is a good choice for constructing tissue engineered bone due to the enhanced new bone formation and osseointegration.

[Osteoblastic differentiation and gene expression profile change in rat bone marrow mesenchymal stem cells after a single period of mechanical strain].

OBJECTIVE: To evaluate the osteoblastic differentiation and compare the difference in the gene expression of rat bone marrow mesenchymal stem cells (MSCs) affected by a single period of mechanical strain. METHODS: Bone marrow MSCs were harvested from the femurs and tibiae of SD rats and cultured in vitro. A four-point bending apparatus were used to perform a single 40-minute period of 2,000 microepsilon mechanical strain on these MSCs. The proliferation of the MSCs was tested by MTT on scheduled date, and the osteoblastic differentiation of the MSCs was measured by testing the expression of osteocalcin and alkaline phosphate (ALP) activity of these cells. In addition, we have investigated the possible mechanisms underlying the action of the single 40-minute period of 2,000 microepsilon mechanical strain on these MSCs, after profile blotted and handled by bioinformation, the gene expressions of these two periods of MSCs were examined. RESULTS: The MSCs have grown well in vitro. Our experiment showed that mechanical environment did not weaken the proliferation of the MSCs. However, the ALP activity and the expression of osteocalcin were significantly up-regulated by the 2,000 microepsilon mechanical strain. Using the 27 K Rat Genome Array, 416 different expressions were found. The rate of different genes was 2.8%, of which the expressions of 247 genes increased (61 genes remarkably increased) and 169 genes decreased (74 genes remarkably decreased) in these two periods of MSCs. CONCLUSION: Mechanical strain induced the osteoblastic differentiation of the MSCs, which may be attributed to the different gene levels.