Culture of rabbit corneal stromal cells on thermo-sensitive materials by the radiation polymerization / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To explore the synthesis of thermo-sensitive poly N-isopropylacry-lamide(PNIPAAm)and the petri dish grafted with PNIPAAm hydrogels by the electron accelerator, as well as the growth conditions and the biological characteristics of rabbit corneal stromal cells on thermo-sensitive PNIPAAm hydrogels, and the cell sheets obtained from the PNIPAAm hydrogels.METHODS: NIPAAm monomer was dissolved in 2-propanol at concentrations of 55% with 0.5% N,N'-Methylenebisacry-lamide(MBA). Solution(70 μL)was added and spread uniformly over 35 mm petri dish. These dishes were immediately subjected to irradiation. After follow-up treatment, rabbit corneal stromal cells were cultured on thermo-sensitive petri dish in vitro.RESULTS: According to the monomer formula and radiation synthesis scheme in this experiment, PNIPAAm can be synthesized on the surface of the petri dish. Rabbit corneal stromal cells grew well in the thermo- sensitive surface and can be separated into sheets.CONCLUSION: The single and multilayer carrier-free cell sheets can be obtained from the use of thermo-sensitive petri dish.

An experimental study on the biological characteristics of SDF-1/CS/β-GP composite bio-membrane in vitro / 口腔医学

Objective@#To prepare a composite membrane by chitosan/β-sodium glycerophosphate(CS/β-GP) thermosensitive hydrogel combined with stromal cell derived factor-1(SDF-1) and observe its biological characteristics in vitro.@*Methods@#Different doses of SDF-1 were added into CS/β-GP solution and then the thermosensitive gel time was measured. The SDF-1/CS/β-GP solution was membrane paved and dried to prepare composite membranes. The morphological characteristics were observed by scanning electron microscope(SEM). Composite membranes were placed into cell culture medium, and the supernatant(n=3) was extracted after standing at 6, 12, 24, 36, 48, 60 h, respectively. The concentration of SDF-1 in the solution was measured. Bone mesenchymal stem cells(BMSCs) were cultured in the Transwell room, and the composite membranes containing different concentrations of SDF-1 were placed in the lower chamber. There were four groups(n=3): Group M0 used CS/β-GP membrane(control group), Group M1, M2, M3 used SDF-1/CS/β-GP membrane(SDF-1 was 100, 200, 400 ng/mL respectively). After culture for 6, 12 and 24 h, the cells under the membrane were preserved and Giemsa stained and counted. The absorbance(OD) value was measured by MTT method to calculate the cell proliferation rate. SPSS 19.0 was used for multi-factor analysis of variance.@*Results @#After adding a certain amount of SDF-1 into CS/β-GP solution, the gel time did not change significantly(P>0.05). The SDF-1/CS/β-GP membrane was translucent and porous at 37 ℃. In this experiment, the volumic mass of SDF-1 released by SDF-1/CS/β-GP composite membrane increased gradually with the experimental time(P<0.01). Transwell cell chemotaxis test showed that the number of BMSCs cells with directional migration increased with the prolongation of observation time(P<0.01) and the increase of SDF-1 volumic mass(P<0.01). In MTT test, the OD value of migration cell solution increased with the prolongation of time(P<0.01) and the increase of SDF-1 volumic mass(P<0.01). @*Conclusion@# The SDF-1/CS/β-GP composite membrane has a porous structure and biological activity of chemotactic BMSCs directional migration. It is a potential membrane for guided tissue regeneration.

The role of thermosensitive transient receptor potential vanilloid channel in the dissimilation of itching sensitized by warm in atopic dermatitis / 中国医师杂志

Atopic dermatitis (AD) is an inflammatory skin disease characterized by itch. Transient receptor potential vanilloid (TRPV) receptor subtype channel can be activated by different ranges of harmless temperature, and plays an important role in the warm itching in AD. Inhibitors of TRPV channel can alleviate the symptoms of AD, and may be used as a new target for treatment. This paper introduces the role of thermosensitive TRPV channel in the alienation of itching sensitized by warm in AD.

A Critical Review on Thermo-Sensitive Vaginal Gel for the Foundation of Preparing Thermo-Sensitive Vaginal Gel of PVK (Panchvalkal Kashaya) Extract

RTI (Reproductive Tract Infection) is the vital cause of suffering in women and neonates. According to WHO estimation 340 million new cases of curable STI (Sexually Transmitted Disease) other than HIV/AIDS occurs every year, most of which are occurring in developing countries. Genital tract infection is the prime cause of most gynaecological disease. Vaginal candidiasis is the most common cause of Genital tract infection. It (Vaginal candidiasis) is a common condition and up to 75% of all women suffer at least one episode of this infection during their life time. For treating the pathological condition of genital tract, direct application or self application of medicine is very difficult and the residence time of the medicine is less due to self cleansing properties of vaginal canal. Application of the drug in other route may cause systemic adverse reaction. To overcome this arduous situation, in situ thermo-sensitive gel form has great importance. In this article an attempt have been made for the review of the thermo-sensitive vaginal gel and the scholar has gathered the basic knowledge to develop an Ayurvedic formulation Panchavalkal kashaya thermo-sensitive vaginal gel by this review. This work will be done in School of Pharmaceutical Science, Shoolini University, Solan, HP.

Preparation, in vitro characterization and pharmacokinetics of paclitaxel thermosensitive gel / 药学学报

Local drug delivery is a new strategy to prevent postoperative recurrence of cancer, thermosensitive gel is a typical topical drug delivery system. In this study, a novel paclitaxel thermosensitive gel (PTG) was prepared to prevent recurrence after chemotherapy for cancer, the effects of drug particle size on release and absorption rate in vivo were investigated. Paclitaxel suspensions with different particle sizes were prepared by medium grinding, high pressure homogenization, air crushing and screening. Using poloxamer as the gel matrix and carbomer as the biological adhesive, Box-Behnen was used to optimize the formulation of PTG. The morphology, viscosity, rheological properties and biological adhesion of thermosensitive gel were characterized. The relationship between dissolution and release of thermosensitive gel was investigated by weight loss method, pharmacokinetics was studied in rats. The paclitaxel suspensions with the particle sizes of 350 nm, 800 nm, 3 μm and 9 μm were prepared, 19% poloxamer 407, 4% poloxamer 188 and 0.1% carbomer were used to prepare PTG. The phase transition temperature of thermosensitive gel was 30 to 35 ℃, there was a good linear relationship between in vitro release and gel dissolution. In the pharmacokinetic study, area under the curve (AUC0-t) increased with the decrease of particle size. In general, the PTG prepared in this study can rapidly change into gel under human body temperature, provided with good adhesion. The release rate in vitro is closely related to the particle size, the release rate increased with the decrease of particle size. This study provides data support for preventing postoperative recurrence of cancer. The animal welfare and experimental process in this paper follow the regulations of the Animal Ethics Committee of the Academy of Military Medical Sciences.

Based on clinical application research progress of thermosensitive gel in different drug delivery sites / 药学学报

The advantages of local administration are as follow: release drugs directly at the lesion, increase the drug concentration in lesion location and reduce the side effects of systemic administration. Thermosensitive gel is one of typical local administration agents. It exhibits the different physical characteristics with the change of temperature. It is sol-gel at low temperature or storage temperature, while when the temperature rises to the transition temperature or near the body temperature, it is semisolid gel with a certain viscoelasticity, and can recover rapidly. It can enhance the local adhesion, which prolongs the local retention time of drugs. As a result, thermosensitive gel can control and display the release of drugs, which can significantly improve the bioavailability of drugs. This review summarizes the characteristics of thermosensitive gel, thermosensitive materials, and its application in different parts: nasal cavity, eye, vagina, periodontal, skin, tumor and joint cavity, based on clinical needs.

Controlled release and cytobiology of recombinant human parathyroid hormone 1-34 mediated by hyaluronic acid thermo-sensitive hydrogels / 药学学报

The bone formation promoter recombinant human parathyroid hormone 1-34 [PTH (1-34)] has a short half-life and low bioavailability. In this study, we prepared a biodegradable and temperature-sensitive hyaluronic acid-poly-N-isopropyl acrylamide (AHA-g-PNIPAAm), and further investigated its effects of PTH (1-34) release and cell behavior as drug carrier. The structure of AHA-g-PNIPAAM was confirmed by hydrogen nuclear magnetic resonance spectroscopy and infrared spectroscopy. Next, PTH (1-34) loaded thermo-sensitive hydrogels were prepared by physical swelling method and their stability was investigated. The morphology of hydrogel was observed by scanning electron microscope. The minimum critical transition temperature and drug release behavior of hydrogels were investigated by ultraviolet spectrophotometry. The tetrazolium-based colorimetric assay (MTT assay) was used to investigate the toxicity and proliferation effects of PTH (1-34)-loaded thermo-sensitive hydrogel on mouse mononuclear macrophage RAW264.7 and mouse precranial osteoblasts MC3T3-E1. The effect of PTH (1-34)-loaded thermo-sensitive hydrogel on the differentiation of RAW264.7 was investigated by the tartrate-resistant acid phosphatase assay. The results showed that the PTH (1-34)-loaded thermo-sensitive hydrogel prepared in this study displayed regular three-dimensional honeycomb structure, and had good stability, thermo-sensitivity and sustained and controlled release properties, which could promote the proliferation of MC3T3-E1 cells more effectively and inhibit the differentiation of RAW264.7 into osteoclasts.

Study of DLTH inhibiting RA by regulating immune function and cartilage degradation / 中国药理学通报

Aim To observe the immune regulation and cartilage protection of dexamethasone-loaded thermosensitive hydrogel (DLTH) on rheumatoid arthritis (RA) rats via conceiving a newly injectable sustained DLTH with chitosan-glycerin-borax as carrier. Methods Thirty rats were randomly divided into three groups, namely control, model and DLTH group. RA model was established through immune induction in model and DLTH group. From the 12th day, rats of DLTH group were injected with 40 (jlL DLTH (1 mg · kg

Construction and in vivo evaluation of a thermosensitive hydrogel system loading with Pseudomonas aeruginosa DNA vaccine / 中国药科大学学报

@#A thermosensitive hydrogel system consisting of PLGA-PEG-PLGA hydrogel and Pseudomonas aeruginosa DNA vaccine was constructed and the immune efficacy of the system was evaluated. The PLGA-PEG-PLGA thermosensitive hydrogel containing Pseudomonas aeruginosa DNA vaccine was prepared by a simple physical mixing method. The gelation temperature, cytotoxicity, and release curve in vitro were tested.The degradability of hydrogel in vivo was evaluated. The mice were divided into control group (PBS), hydrogel group (Hydrogel), in vivo-jetPEI/plasmid DNA group (in vivo-jetPEI/pDNA), and hydrogel + in vivo-jetPEI/plasmid group (Gel+in vivo-jetPEI/pDNA). Mice were immunized three times with a ten-day interval. Two weeks after the last immunization, the mice were sacrificed. The proliferation of splenic lymphocytes, serum specific IgG antibodies and IFN-γ in supernatant of splenic lymphocytes were detected. The gelation temperature of PLGA-PEG-PLGA hydrogel was (32 ± 0.5) ℃. There was no obvious toxicity to cells in vitro, and about 80% of plasmid DNA was released after 7 days in vitro. PLGA-PEG-PLGA hydrogel was biodegradable, and degraded almost completely after 15 days in vivo. The spleen lymphocytes proliferated; the levels of specific IgG antibodies and IFN-γ of in vivo-jetPEI/pDNA and Gel+in vivo-jetPEI/pDNA groups increased. The hydrogel could enhance the immune response induced by DNA vaccine.Results suggest that the thermosensitive hydrogel system consisting of PLGA-PEG-PLGA hydrogel and Pseudomonas aeruginosa DNA vaccine is a promising new strategy for the development of PA vaccine.

Preparation and in vivo and in vitro Characteristic Evaluation of Ligustrazine Ophthalmic Liposome Thermosen- sitive Gel / 中国药房

OBJECTIVE：To prepare Liguatrazine opthalmic liposome therm osensitive gel ，and to investigate its in vivo and in vitro characteristics. METHODS ：The ammonium sulfate gradient method was used to prepare Liguatrazine liposomes. The preparation technology was optimized by using orthogonal test. Using poloxamer P 407 as gel matrix ，Liguatrazine liposomes were prepared into thermosensitive gel. A membraneless model was used to study the dissolution and in vitro drug release of the gel. The modified Franz diffusion cell was used to investigate corneal permeability and further determine corneal hydration value. The effects of the gel on the proliferation of human corneal epithelial cell HCE-T. HE staining and Draize test were used to investigate the stimulatory effects of the gel on corneal cells of the rabbit ，and the histological changes of the eyes were observed. RESULTS ：The optimal preparation technology of Liguatrazine liposome was drug-lipid ratio of 1 ∶ 10（m/m），the ammonium sulfate concentration of 0.2 mol/L，phospholipid-cholesterol ratio of 4∶1（m/m），incubation temperature of 45 ℃. Then ligustrazine opthalmic liposome thermosensitive gel was prepared with 23％ poloxamer P 407 as gel matrix. The gel had good gelatinization temperature. The in vitro drug release and dissolution showed zero-order kinetic characteristics ，and in vitro drug release of the gel was mainly related to dissolution （R2＝0.993 4）. The cumulative transcorneal permeability of the gel was 43.3％ within 6 hours and corneal hydration value was 72.98％. Low and medium concentrations （1，5 mg/L）of Ligustrazine opthalmic liposome thermosensitive gel had no obvious proliferation toxicity to HCE-T cells ，but it showed cytotoxicity at high concentration （10 mg/L）. The mean Draize eyeirritation score of the gel on rabbit cornea was within non-stimulation，and there was no abnormal change in rabbit （No.2018001） corneal histology. CONCLUSIONS ： Prepared Ligustrazine opthalmic liposome thermosensitive gel has a suitable phase transition temperature ，good corneal permeability ，and low corneal irrit ation.

Thermosensitive In Situ Gel Of Tinidazole In Treatment Of Bacterial Vaginosis: Formulation And Evaluation

Bacterial Vaginosis (BV) is the leading cause of vaginal discharge. Because of its big surface area, wealthy blood supply, avoidance of the first-pass effect and high permeability to many drugs, the vagina offers a promising location for local impact as well as systemic drug delivery. In situ gels give several benefits, such as ease of administration in the respective body cavities, elevated spreadability at certain temperatures, reduced administration frequency, improved patient compliance and comfort compared to standard dosage forms. Tinidazole (TNZ) can give effective treatment over the BV. In situ gel of TNZ containing polaxomer 407and HPMC E100 or carbopol 941NF was optimized on the basis of various evaluation parameters. Gelation temperature (Tgel) and pH of all batches was found in range of 36.6 to38.0 ºC and 4.20 to 5.03, viscosity was found in range of 1100-2050 cps at 25ºC and 4800-6530 cps at 37ºC. The Spredability was found in range of 16-20 cm. From these evaluation parameters we selected best combination for the mucoadhesive property, antimicrobial study, in vitro drug release and for HET CAM irritation study. The optimized formulation gives satisfactory results. In this study we also compare the performance of two mucoadhesive polymer. Based on maximum desirability and cost effectiveness, in situ vaginal gel containing 20% polaxomer and 0.5% HPMC E100 could be considered as a highly promising treatment for bacterial vaginosis.

Formulation Optimization of Citalopram Hydrobromide Thermosensitive Nasal Gel and Its In Vitro Properties / 中国药学杂志

OBJECTIVE: To optimize the formulation of citalopram hydrobromide (CTH ) thermosensitive nasal gel and further evaluate its in vitro properties. METHODS: With gelling temperature and gelling time as evaluating indexes, central composite design-response surface and single factor experimental design method were used to optimize the formulation of CTH thermosensitive nasal gel by using poloxamer 407(F127) and carbomer 940 (CP940) as gel materials. Meanwhile, nasal mucosa permeation enhancer for CTH was then sieved by using Franz diffusion cell and ex vivo sheep nasal mucosa as experimental model. Finally, CTH thermosensitive nasal gel was prepared with cold method and then its in vitro properties was evaluated. In vitro cumulative erosion and cumulative release rate of the drug thermosensitive nasal gel were investigated by membrane-free dissolution method and dialysis membrane method, respectively. Moreover, the effect of temperature and pH on the viscosity of the drug nasal gel formulation was also evaluated. RESULTS: The optimal formulation of the thermosensitive nasal gel consisted of CTH 8.0%, F127 20.27%, CP940 0.17%, DM-β-CD 3.0%, ethylparaben 0.05% and distilled water. The gelling temperature, gelling time and pH of the drug thermosensitive nasal gel were found to be about 32.5 ℃,42 s and 5.0, respectively. The in vitro cumulative erosion and cumulative release percentage were both greater than 90% in 55 min and furthermore there was good linear correlation between these two parameters (r=0.998 6). Additionally, in vitro cumulative release of the drug from the gel formulation was determined to be 92% within 8 h, which conformed to Higuchi kinetic equation. Furthermore, the viscosity of the drug nasal gel was influenced by temperature as well as pH in different extent. CONCLUSION: The optimized formulation of the CTH thermosensitive nasal gel with central composite design-response surface method and single factor design method shows suitable gelling temperature, gelling time, pH value for nasal preparation and obvious in vitro drug sustained release characteristics.

Pharmacokinetics and Brain Delivery of Citalopram Hydrobromide Thermosensitive Nasal Gel in Rats / 中国药学杂志

OBJECTIVE: To investigate the pharmacokinetics of citalopram hydrobromide(CTH)thermosensitive nasal gel and further evaluate its brain delivery in rats. METHODS: The concentrations of CTH in rat plasma and brain tissue were determined by HPLC method. With intragastric administration (ig) of CTH solution as control, CTH thermosensitive nasal gel was intranasally given to rats and the concentrations of CTH in plasma and brain tissues were then determined. Moreover, the main pharmacokinetic parameters of CTH in plasma and brain tissues such as tmax, ρmax,relative bioavailability (Fr) and drug targeting efficiency (DTE) were estimated. RESULTS: Main pharmacokinetic parameters of CTH following nasal and ig administration to rats such as tmax and ρmax were 5 and 45 min, 2 152.86 and 589.68 ng•mL-1 in plasma, and 5 and 45 min, 17 660.56 and 1 171.68 ng•g-1 in brain tissue, respectively. Finally, the Fr and DTE of CTH thermosensitive nasal gel were found to be 184.91% and 250.03%, respectively. CONCLUSION: CTH thermosensitive nasal gel may be an ideal non-oral new dosage form with many advantages such as rapid in vivo absorption, high bioavailability and obvious brain delivery characteristics.

Thermosensitive gel of polysaccharide from Ganoderma applanatum combined with paclitaxel for mice with 4T1 breast cancer / 中国中药杂志

Polysaccharide from Ganoderma applanatum has the activities of anti-tumor and enhancing immune function. There were no reports on antitumor effect of its intratumoral injection. In this study, the polysaccharide was extracted from G. applanatum by water extraction and alcohol precipitation, and purified by ceramic membrane after removing protein by Sevage method. The total polysaccharide content from G. applanatum(PGA)was about 63%. The combination of PGA and paclitaxel showed synergistic effect on cytotoxicity of 4 T1 cells at lower concentrations in vitro. In addition, the growth curve of 4 T1 cells showed that PGA could retard the growth of 4 T1 cells gradually. The PGA thermosensitive gel(PGA-TG)was prepared by using poloxamer 188 and 407. The gel temperature was 36 ℃, and the PGA-TG could effectively slow down the release rate of PGA in vitro. 4 T1 breast cancer-bearing mice were used as a model to evaluate the therapeutic effect of intratumoral injection of PGA combined with tail vein injection of nanoparticle albumin-bound paclitaxel(nab-PTX). In high and low dose PGA groups, each mice was given with 2.25, 1.125 mg PGA respectively, twice in total, and the dosage of paclitaxel was 15 mg·kg~(-1), once every 3 days, for a total of five times. The tumor inhibition rate was 29.65% in the high dose PGA-TG group, 58.58% in the nab-PTX group, 63.37% in low dose PGA-TG combined with nab-PTX group, and 68.10% in high dose PGA-TG combined with nab-PTX group respectively. The inhibitory effect in high dose PGA-TG group combined with nab-PTX on tumors was significantly higher than that in nab-PTX group(P<0.05). The results showed that paclitaxel therapy combined with intratumoral injection of PGA-TG could improve the therapeutic effect for 4 T1 mice and reduce the side effects of chemotherapy.

Application of TTI in quality control of the military thermo-sensitive drugs / 药学实践杂志

To ensure the safety and efficacy of the military thermo-sensitive drugs, it is necessary to monitor the temperature changes through the whole process of production, transportation, storage, distribution and application. The characteristics of various commercial TTI were analyzed. The applications of TTI technology in the quality control for military thermo-sensitive drugs were reviewed in order to provide accurate quality assurance for those drugs.

Rheology and in vitro release properties of thermosensitive in situ gel of Yihuang Decoction and its common gel for vaginal use / 中国中药杂志

To evaluate the traits and rheological properties of thermosensitive in situ gel of Yihuang Decoction and its common gel for vaginal use, and predict the release behavior of Yihuang Decoction in situ gel in vitro. Poloxamer was used as thermosensitive material to prepare Yihuang Decoction vaginal in situ gel, and Yihuang Decoction common gel was prepared with carbopol. Then the differences of the two gels before and after diluting with vaginal fluid were compared. The rheological parameters of Yihuang Decoction in situ gel and its common gel were determined with Anton Paar MCR102 rheometer. In addition, berberine hydrochloride was selected as an index component to evaluate the in vitro release properties of Yihuang Decoction vaginal thermosensitive in situ gel. Yihuang Decoction vaginal thermosensitive in situ gel was Newtonian fluid under low-temperature conditions, which was yellow and transparent. After reaching the gelling temperature of 24.5 ℃, it became semi-solid, pseudoplastic fluid. The gelling temperature was predicted to be 37 ℃, and the phase transition time was 30 s after diluting with simulated vaginal fluid. However, the rheological properties of Yihuang Decoction common gel had no significant changes with temperature. Compared with in situ gel, the color of common gel was darker and more translucent. Besides, its mobility was stronger after diluting with simulated vaginal fluid. The in vitro release study showed that the kinetic behavior of berberine hydrochloride in Yihuang Decoction vaginal thermosensitive in situ gel was matched with the Higuchi equation. Through simulation of vaginal administration, physical properties and dynamic rheological parameters were used to intuitively and scientifically evaluate the two gels. Compared with the common gel, the thermosensitive in situ gel could quickly attached to the vaginal mucosa and release drug, and thus was more suitable for developing vaginal administration of Yihuang Decoction, which also provides references for studying new vaginal preparation of Yihuang Decoction.

Preparation of Periplaneta americana Thermosensitive Hydrogel and Investigation of Its Wound Healing Effect on Diabetic Rats / 中国实验方剂学杂志

Objective:To prepare Periplaneta americana thermosensitive hydrogel and investigate its effect on wound healing in diabetic rats. Method:Taking N-isopropylacrylamide (NIPAM) and acrylic acid (AAc) as monomers, thermosensitive poly(NIPAM-co-AAc) [P(NIPAM-co-AAc)] polymeric material was prepared by free radical polymerization, then thermoresponsive copolymer P(NIPAM-co-AAc)-g-HA was synthesized by conjugating P(NIPAM-co-AAc) to hyaluronic acid (HA). The structure and lower critical solution temperature (LCST) of the graft copolymer were characterized by proton nuclear magnetic resonance spectroscopy (1H-NMR) and ultraviolet spectrophotometry (UV). P. americana thermosensitive hydrogel was prepared by dialysis method, and it was characterized by scanning electron microscope (SEM), rotation rheometer and thermogravimetric analyzer to observe section structure, rheological properties and thermal stability. Differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy were employed to identify the inclusion of P(NIPAM-co-AAc)-g-HA temperature sensitive material for P. americana extract, and to investigate the effect of P. americana thermosensitive hydrogel on wound healing in diabetic rats, and the rate of wound healing was calculated by Image-Pro Plus 6.0 software. Hematoxylin-eosin (HE) and Masson staining were used to observe the pathological changes of the wounds of rats in each group. Result:P(NIPAM-co-AAc)-g-HA temperature sensitive material was successfully synthesized, its LCST was between 29 ℃ and 31 ℃, it had a dense and uniform porous structure and could uniformly include P. americana extract. Pharmacodynamic studies showed that P. americana thermosensitive hydrogel group had the best effect on promoting wound healing, its infiltration degree of inflammatory cells was significantly reduced, collagen and fibroblasts arranged neatly and compactly, and the density of neovascularization was significantly increased by comparing with the model group. Conclusion:P. americana thermosensitive hydrogel can effectively promote wound healing of diabetic rats and overcome the shortage of marketed P. americana liquid preparations, this paper can provide a reference for the development of P. americana extract preparations to promote wound healing in diabetic patients.

A green route for the fabrication of thermo-sensitive chitosan nerve conduits and their property evaluation / 中国修复重建外科杂志

Objective: To explore a green route for the fabrication of thermo-sensitive chitosan nerve conduits, improve the mechanical properties and decrease the degradation rate of the chitosan nerve conduits. Methods: Taking advantage of the ionic specific effect of the thermo-sensitive chitosan, the strengthened chitosan nerve conduits were obtained by immersing the gel-casted conduits in salt solution for ion-induced phase transition, and rinsing, lyophilization, and 60Co sterilization afterwards. The nerve conduits after immersing in NaCl solutions for 0, 4, 12, 24, 36, 48, and 72 hours were obtained and characterized the general observation, diameters and mechanical properties. According to the above results, the optimal sample was chosen and characterized the microstructure, degradation properties, and cytocompatibility. The left sciatic nerve defect 15 mm in length was made in 20 male Sprague Dawley rats. The autologous nerves (control group, n=10) and the nerve conduits (experimental group, n=10) were used to repair the defects. At 8 weeks after operation, the compound muscle action potential (CMAP) was measured. The regenerated nerves were investigated by gross observation and toluidine blue staining. The gastrocnemius muscle was observed by HE staining. Results: With the increased ionic phase transition time, the color of the conduit was gradually deepened and the diameter was gradually decreased, which showed no difference during 12 hours. The tensile strength of the nerve conduit was increased gradually. The ultimate tensile strength showed significant difference between the 48 hours and 12, 24, and 36 hours groups ( P0.05). As a result, the nerve conduit after ion-induced phase transition for 48 hours was chosen for further study. The scanning electron microscope (SEM) images showed that the nerve conduit had a uniform porous structure. The degradation rate of the the nerve conduit after ion-induced phase transition for 48 hours was significantly decreased as compared with that of the conduit without ion-induced phase transition. The nerve conduit could support the attachment and proliferation of rat Schwann cells on the inner surface. The animal experiments showed that at 8 weeks after operation, the CMAPs of the experimental and control groups were (3.5±0.9) and (4.3±1.1) m/V, respectively, which showed no significant difference between the two groups ( P0.05］. The nerve conduit of the experimental group could repair the nerve defect. There was no significant difference between the experimental and control groups in terms of the histomorphology of the regenerated nerve fibers and the gastrocnemius muscle. Conclusion: The green route for the fabrication of thermo-sensitive chitosan nerve conduits is free of any toxic reagents, and has simple steps, which is beneficial to the industrial transformation of the chitosan nerve conduit products. The prepared chitosan nerve conduit can be applied to rat peripheral nerve defect repair and nerve tissue engineering.

The preparation of VEGF/bFGF-loaded poloxamer thermosensitive gels and the promotive effect of the gels on the skin wound healing in rats / 国际药学研究杂志

Objective: To prepare the vascular endothelial growth factor(VEGF)and basic fibroblast growth factor(bFGF)-loaded poloxamer thermosensitive gels and investigate the in vitro drug release property as well as the therapeutic effect of the drug-loaded thermosensitive gels on the full-thickness skin defected wound healing in rats. Meth- ods: The release of VEGF and bFGF from the drug-loaded gels in vitro was determined by the membrane release meth- od. The full-thickness skin defected model of rats was established and divided into four groups: the normal saline(Con- trol)group, poloxamer thermosensitive gel(Gel)group, freeze-dried VEGF and bFGF powder(VEGF/bFGF powder) group, and the VEGF/bFGF-loaded poloxamer thermosensitive gel(VEGF/bFGF-loaded gel)group. The wound healing was observed on the 3rd, 7th and 14th day of injury. The wound tissue was stained with hematoxylin-eosin. The wound healing and inflammation were observed under the microscope. The expression of CD31 was measured by the immunohis- tochemical staining and the number of new blood vessels was counted. The content of inflammatory factors in the wound was detected by ELISA. Results: The VEGF/bFGF-loaded poloxamer thermosensitive gels were successfully prepared. The in vitro drug release test showed that only about 5% of VEGF and bFGF in the drug-loaded gels was released from the gels within 1 h of the test, however, the subsequent VEGF and bFGF release could reach 60% on the fifth day of the re- lease test, suggesting the well sustained drug-release behavior of the VEGF/bFGF-loaded gels. In the wound healing test using the full-thickness skin defected rat model, the wound healing rate reached(90.3±2.4)% on the 14th day of injury, in the VEGF/bFGF-loaded gel group, which was significantly higher than that in the other groups(P<0.05). On the 3rd day of injury, compared with the Control and Gel groups, the level of IL-6 and TNF-α in the wound was significantly de- creased in the VEGF/bFGF-loaded gel group(P<0.05). The tissue HE staining showed that the skin wound healed well in the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups, and a lager number of neovascularization and the epi- dermis appeared earlier in both the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups than in the Control and the Gel groups. The immunohistochemical results further confirmed that the number of neovascularization was significant- ly higher in the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups than in the Control and Gel groups(P< 0.05). Conclusion: The prepared VEGF/bFGF-loaded poloxamer thermosensitive gels in the present study could be used to repair the full-thickness skin defected wound in rats, which could reduce the early inflammatory reaction, pro- mote the angiogenesis, and thus accelerate the healing.

Preventive effect of thermosensitive hydroxybutyl chitosan hydrogel in intrauterine adhesion in New Zealand white rabbits / 上海交通大学学报（医学版）

Objective: To observe the effect of thermosensitive hydroxybutyl chitosan (HBC) hydrogel in the prevention of intrauterine adhesion in New Zealand white rabbits. Methods: Eighteen female New Zealand rabbits were randomly divided into 3 groups, i. e., normal control group, model group and HBC group. Normal control group underwent sham operation. The models of intrauterine adhesion were constructed by both mechanical damage and infection in model group and HBC group. In HBC group, 2 mL 1.5% thermosensitive HBC hydrogel was injected into the uterine cavity immediately after injury. Two rabbits were killed in each group 1 week, 2 weeks and 4 weeks after operation, respectively. The bilateral uterine tissues were collected. The endometrial morphology and quantity of glands were observed by hematoxylin-eosin staining. The area of fibrosis in endometrium was measured by Masson staining. Results: One week after operation, compared with normal control group, the columnar epithelial cells of endometrium gradually disappeared and the ratio of endometrial fibrosis area increased significantly in the other two groups. The number of glands also decreased. After 2 weeks, intrauterine adhesion was observed in model group, and the ratio of endometrial fibrosis area continued increasing, and the number of glands decreased further. However, in HBC group, there was no residual hydrogel in the uterine cavity, and the ratio of endometrial fibrosis area decreased and the number of glands increased. After 4 weeks, there was a recovery of columnar epithelium cells, the ratio of endometrial fibrosis area, and the number of glands in HBC group, which returned to the normal level. Conclusion: Thermosensitive HBC hydrogel can effectively prevent intrauterine adhesion in New Zealand white rabbits.