A Novel Use of Genipin-Fixed Gelatin as Extracellular Matrix for Peripheral Nerve Regeneration

Application of combining herbal medicine and biomedical material science to nerve regeneration is a new approach. In this study, we describe a novel use of purified genipin, which can be extracted from Gardenia jasminoides Ellis, fixing the gelatin to be an extracellular matrix for peripheral nerve regeneration. A 10-mm gap of rat sciatic nerve was created between the proximal and distal nerve stumps, which were sutured into silicone rubber tubes filled with either the genipin-fixed gelatin or collagen gel. Silicone rubber tubes filled with saline were used as controls. Six weeks after implantation, regeneration across the nerve gaps occurred in 80 and 90% of the animals from the groups of genipin-fixed gelatin and collagen, respectively, whereas only 30% in the control group. Large numbers of myelinated axons were also seen in the genipin-fixed gelatin (5104±3278) and the collagen groups (8063±1807). These findings indicated that the genipin-fixed gelatin could be an acceptable extracellular matrix for nerve regeneration.

[HPLC Analyzed the Iridoid Glycosides of Qingyedan Commonly Used in Folk Medicine in Yunnan]

OBJECTIVE

To compare the contents of iridoid glycosides in Qingyedan medicinal materials,and to provide the scientific basis for using resources of Qingyedan and rationality of original plant medicinal.

METHODS

The contens of three iridoid glycosides,including swertiamarin,gentiopicroside and sweroside in Qingyedan medicinal materials were determined by HPLC.

RESULTS

The constituents of 30 samples in nine species were significant difference. And the contents of iridoid glycosides in Swertia bimaculata,Swertia tenuis and Swertia pubescens were reported for the first time.

CONCLUSION

The results show that the contents of iridoid glycosides in Qingyedan medicinal materials have a significant difference due to the different species and producing areas. Therefore, these medicinal plants should not be used as alternative medicines for clinical application. Swertiamarin and sweroside can be selected as quality control components, this method is an effective method to identify and control the quality of Qingyedan materials.

Influence of cross-linking degree of a biodegradable genipin-cross-linked gelatin guide on peripheral nerve regeneration

We evaluated peripheral nerve regeneration using biodegradable genipin-cross-linked gelatin nerve conduits (GGCs) with three different cross-linking degrees, 24, 36 and 51%. Biocompatibility and biodegradability of the GGC and its efficiency as a guidance channel were examined based on the repair process of a 10-mm gap in the rat sciatic nerve. From this pilot study we concluded that GGCs with a mean cross-linking degree of 36% can ensure nerve regeneration with a more mature structure, as demonstrated by better developed epineural and perineural organisation and axonal development, as well as better-recovered electrophysiology with a relatively positive sciatic functional index and a shorter latency of the muscle action potential curve. Regenerated nerves in the GGCs with mean cross-linking degrees of 24 and 51% were less favourable, due to irritation caused by degradation material and compression by the remaining tube walls, respectively.

pH-sensitive behavior of two-component hydrogels composed of N,O-carboxymethyl chitosan and alginate

A two-component pH-sensitive hydrogel system composed of a water-soluble chitosan derivative (N,O-carboxymethyl chitosan, NOCC) and alginate cross-linked by genipin, glutaraldehyde or Ca2+ was investigated. Preparation and structures of these hydrogels and their swelling characteristics and release profiles of a model protein drug (bovine serum albumin, BSA) in simulated gastrointestinal media are reported. At pH 1.2, the swelling ratios of the hydrogels cross-linked by distinct methods were limited. Of note is that the lowest swelling ratios of test hydrogels were found at pH 4.0. At pH 7.4, the carboxylic acid groups on test hydrogels became progressively ionized and led to a significant swelling. There was barely any BSA released from the glutaraldehyde-cross-linked hydrogel throughout the entire course of the study. The amounts of BSA released at pH 1.2 from the genipin- and Ca(2+)-cross-linked hydrogels were relatively low (approx. 20%). At pH 4.0, there was still significant BSA release from the Ca(2+)-cross-linked hydrogel, while the cumulative BSA released from the genipin-cross-linked hydrogel was limited due to its shrinking behavior. At pH 7.4, the amount of BSA released from the genipin- and Ca(2+)-cross-linked hydrogels increased significantly (approx. 80%) because the swelling of both test hydrogels increased considerably. The aforementioned results indicated that the swelling behaviors and drug-release profiles of these test hydrogels are significantly different due to their distinct cross-linking structures.

[Determination of harpagide and harpagoside in Scrophulariae Radix by HPLC-UV]

OBJECTIVE

To develop a method for the determination of harpagide and harpagoside in Scrophulariae Radix (Xuanshen) by HPLC-UV under double wavelength, and to study the changes of these two constituents during processing, and to set the limitation of harpagide and harpagoside contents in crude drug and sliced pieces of Xuanshen.

METHOD

The analyses were performed on an Agilent Technologies ZORBAX SB-C18 (4.6 mm x 250 mm, 5 microm) eluted with acetonitrile-water (containing 0.03% phosphoric acid) in gradient model. The flow rate was 1.0 mL x min(-1) . The column temperature was 25 degrees C. The UV detector wavelength was set at 210 nm before 13 min and then changed to 280 nm.

RESULT

Harpagide and harpagoside were separated well. The linear calibration curves were obtained over of 0.0549 - 1.46 microg for harpagide (r = 0.9999, n =7) ,0.0225 - 0.900 microg for harpagoside (r = 0.9998, n = 9). The recoveries ( +/- RSD)% were 98.1 (+/- 2.4)% for harpagide and 98.8 (+/- 4.3)% for harpagoside. The contents of harpagide were 0. 277% - 0.620%, harpagoside were 0.078% - 0.362% in Xuanshen, and harpagide were 0.276% - 1.059%, harpagoside were 0. 059% - 0.183% in sliced Xuanshen, respectively. After the processing of Scrophulariae Radix, the content of harpagide increases 13.7% - 96.0%, while harpagoside decreases 11.0%-73.9%.

CONCLUSION

This method is simple, accurate, and can be used for the quality control of Scrophulariae Radix. We propose that the total content of harpagide and harpagoside in either crude drug or sliced pieces of Scrophulariae Radix should not be less than 0.45%.

[Simultaneous determination of five constituents in Scrophularia ningpoensis by HPLC]

OBJECTIVE

To develop an HPLC method for the simultaneous quantitation of five constituents in Scrophularia ningpoensis.

METHOD

Samples were analyzed on an Agilent SB-C18 column(4.6 mm x 250 mm, 5 microm) eluted with acetonitrile and water containing 0.03% phosphate acid as mobile phases in a linear gradient mode. The flow rate was kept at 1.0 mL x min(-1), and the column temperature was set to 30 degrees C. The DAD detector wavelengths were 210, 280, 330 nm.

RESULT

The linear ranges were 50-400 mg x L(-1) for harpagide, 1-40 mg x L(-1) for harpagoside, 1-20 mg x L(-1) for cinnamic acid, 0.5-4.5 mg x L(-1) for acteoside,1-60 mg x L(-1) for angoroside C, respectively. The average recoveries of the five constituents were 100.8% (RSD 0.62%), 101.7% (RSD 0.32%), 98.8% (RSD 0.48%), 99.9% (RSD 1.4%), 99.2% (RSD 1.1%), respectively.

CONCLUSION

Through the validation, the method was proved to be sensitive, accurate, repeatable, and can be used for quality control of the roots of S. ningpoensis.

Anti-inflammatory effect of Ajuga bracteosa Wall Ex Benth. mediated through cyclooxygenase (COX) inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Ajuga bracteosa Wall Ex Benth. (Labiateae) is described in Ayurveda for the treatment of rheumatism, gout, palsy and amenorrhea.

AIM OF THE STUDY

The aim of present investigation is to study anti-inflammatory activity of Ajuga bracteosa, to understand possible mechanism of action and to identify the constituents responsible for its activity.

MATERIALS AND METHODS

The anti-inflammatory activity of 70% ethanolic extract was evaluated in TPA-induced mouse ear edema assay and in vitro cyclooxygenase (COX)-1 and COX-2 inhibitory activity was determined using EIA kits employing appropriate reference standards. Aajugarin I, lupulin A, withaferin A, reptoside and 6-deoxyharpagide were isolated from the 70% ethanolic extract by silica gel column chromatography.

RESULTS

The 70% ethanol extract of whole plants of Ajuga bracteosa showed a significant (p<0.05) and dose-dependent anti-inflammatory activity in an acute inflammation model at the dose of 0.5 and 1.0 mg/ear. The extract also exhibited a strong in vitro COX-1 and COX-2 inhibitory activity at 25 and 50 μg/mL concentration. Among the isolated compounds 6-deoxyharpagide exhibited highest COX-2 inhibition while rest of the compounds exhibited weak to moderate COX-1 and COX-2 inhibition at 30 μM concentration.

CONCLUSIONS

The results suggest that the 70% ethanol extract of Ajuga bracteosa possesses promising anti-inflammatory activity, which is possibly mediated through inhibition of COX-1 and COX-2 enzymes. The isolated constituents could be responsible in part for its anti-inflammatory and COX inhibitory activity. The study supports traditional use of Ajuga bracteosa for inflammatory diseases.

Iridoid glycosides from Saprosma ternatum

Three new iridoid glycosides, epiasperuloside (1), epipaederosidic acid (2), and epipaederoside (3), together with 7 known compounds, were isolated from the 85% ethanol extract of the leaves of Saprosma ternatum Hook. f. Their structures were determined by application of spectroscopic (NMR, MS) and chemical methodologies. The antioxidant activity was evaluated for all isolates in terms of both DPPH and ABTS bioassays. Epiasperuloside (1) showed some antioxidant activity.

Two new secoiridoid glycosides from Verbena officinalis

Two new secoiridoid glycosides, verbenoside A (1) and verbenoside B (2), have been isolated from the ethanol extract of the aerial parts of Verbena officinalis L. Their structures were elucidated on the basis of spectroscopic evidences, especially 1D, 2D NMR, and MS experiments.

Two new dimeric secoiridoid glycosides from the fruits of Ligustrum lucidum

Two new secoiridoid glycosides, ligusides A and B (1 and 2), as well as seven known compounds (3-9), were isolated from the fruits of Ligustrum lucidum. Their structures were elucidated on the basis of spectroscopic and chemical analysis.

Three new secoiridoid glycoside dimers from Swertia mileensis

Three new secoiridoid glycoside dimers named swerilactosides A-C (1-3) were isolated from Swertia mileensis. Their structures were elucidated based on extensive spectral analyses (1D and 2D NMR, MS, and IR spectroscopic means).

Investigation on magnetically controlled delivery of doxorubicin from superparamagnetic nanocarriers of gelatin crosslinked with genipin

Gelatin (Type B) nanoparticles were prepared by a single W/O emulsion technique and characterized by infrared (IR) spectra, transmission electron micrographs (TEM), surface potential measurements and magnetization studies. Whereas the IR spectra clearly confirmed the presence of gelatin, genipin and doxorubicin in the loaded nanoparticles, the transmission electron micrographs (TEM) image depicts smooth surface, spherical shape and non-uniform size of nanoparticles (up to 100 nm). The prepared nanoparticles were loaded with doxorubicin, a well known anticancer drug, and in vitro release dynamics of entrapped drug was investigated as a function of various experimental factors such as percent loading of the drug, chemical architecture of the nanocarriers, and pH, temperature, ionic strength and nature of the release medium in presence and absence of magnetic field. The nanoparticles were also studied for their water sorption capacity. The drug release process was analyzed kinetically using Ficks power law and a correlation was established between the quantity of released drug and swelling of the nanoparticles.

Kinetic characterization and comparison of various protein crosslinking reagents for matrix modification

We have characterized the relative efficacies of a number of protein crosslinking agents that have the potential for use in the crosslinking of proteinaceous matrices both in vitro and in vivo. The crosslinkers tested were; L: -threose (LT), Genipin (GP), Methylglyoxal (MG), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), proanthrocyanidin (PA) and glutaraldehyde (GA). The relative effectiveness of the crosslinkers with regard to their saturating concentrations was: GA > PA > EDC > MG = GP >> LT. Most of the crosslinkers displayed a pH dependence and were more effective at more alkaline pH. At optimal pH and saturating conditions, the relative reaction rates of the crosslinkers were: PA = GA > EDC > GP > MG >> LT.

Active ingredients of traditional Japanese (kampo) medicine, inchinkoto, in murine concanavalin A-induced hepatitis

AIM OF THE STUDY

The traditional Japanese (kampo) medicine inchinkoto (ICKT) is used in Eastern Asia as a choleretic and hepatoprotective agent. Previously, we reported that ICKT ameliorates murine concanavalin A (con A)-induced hepatitis via suppression of interferon (IFN)-gamma and interleukin (IL)-12 production. In the present study, we investigated the active ingredients of ICKT.

MATERIALS AND METHODS

ICKT and extracts of its component herbs were fractionated, and their effects on liver injury and cytokine production in vivo (biochemical markers of liver injury and cytokine levels in serum) and in vitro (cytokine and nitrite production in the cultures of splenocytes and peritoneal macrophages).

RESULTS

Decoctions of component herbs, Artemisiae Capillari Spica (Artemisia capillaris Thunberg: 'Inchinko' in Japanese), Gardeniae Fructus (Gardenia jasminoides Ellis: 'Sanshishi') and Rhei Rhizoma (Rheum palmatum Linné: 'Daio') were administered orally. Inchinko and Sanshishi decreased serum transaminases and IFN-gamma concentrations. Examination of fractions of component herbs suggested that capillarisin, a component of Inchinko, has potent hepatoprotective activity in vivo. In in vitro studies, capillarisin and genipin, an intestinal metabolite of geniposide that is contained in Sanshishi, were examined. IFN-gamma production was significantly suppressed by capillarisin and genipin in con A-stimulated splenocyte culture. Genipin also suppressed IL-1beta, IL-6, and IL-12p70 synthesis. Capillarisin and genipin decreased nitrite release from IFN-gamma-stimulated macrophages.

CONCLUSIONS

These results suggested that both Inchinko and Sanshishi may contribute to the protective effects of ICKT against con A hepatitis. Capillarisin was found to be potently hepatoprotective, and genipin may also contribute, especially via modulation of cytokine production.

In vitro study in the endothelial cell compatibility and endothelialization of genipin-crosslinked biological tissues for tissue-engineered vascular scaffolds

To overcome the cytotoxicity of the chemical reagents used to fix bioprostheses, genipin, a naturally occurring crosslinking agent, was used to fix biological tissues in present study. We prepared the biological vascular scaffolds through cell extraction and fixing the porcine thoracic arteries with 1% (by w/v) genipin solution for 3 days, and then examined their mechanical properties and microstructures; glutaraldehyde- and epoxy-fixed counterparts were used as controls. HUVECs were seeded on the type I collagen-coated surface of different modified acellular vascular tissues (fixed with different crosslinking agents), and the growths of HUVECs on the specimens were demonstrated by means of MTT test, the secretion of PGI2 and vWF by HUVECs on the various specimens was also measured. Finally, HUVECs were seeded on the luminal surface of acellular biological vascular scaffolds (<6 mm internal diameter) which were, respectively, treated in the same manner described above, and then cultured for 9 days. On the ninth day, the HUVECs on the luminal surface of these vascular scaffolds were examined morphologically and by immunohistochemistry. Genipin-fixation can markedly diminish antigenicity of the vascular tissues through partially getting rid of cell or reducing the level of free amino groups in the vascular tissues. Genipin-fixed acellular vascular tissues mimicked the natural vessels due to the maintenance of the integrity of total structure and the large preservation of the microstructures of collagen fibers and elastic fibers; therefore, it appeared suitable to fabricate vascular scaffolds in mechanical properties. Compared to controls, the genipin-fixed acellular vascular tissues were characterized by low cytotoxicity and good cytocompatibility. The HUVECs can not only proliferate well on the genipin-fixed acellular vascular tissues, but also preserve the activities and function of endothelial cells, and easily make it endothelialized in vitro. The results showed that the genipin-fixed acellular porcine vascular scaffolds should be promising materials for fabricating vascular grafts or the scaffolds of tissue-engineered blood vessels.

Iridoids from Fraxinus excelsior with adipocyte differentiation-inhibitory and PPARalpha activation activity

Two new secoiridoid glucosides, excelsides A (1) and B (2), were isolated from the seeds of Fraxinus excelsior. Their structures were elucidated as (2S,4S,3E)-methyl 3-ethylidene-4-(2-methoxy-2-oxoethyl)-2-[(6-O-beta-D-glucopyranosyl-beta-d-glucopyranosyl)oxy]-3,4-dihydro-2H-pyran-5-carboxylate and (2S,4S,3E)-methyl 3-ethylidene-4-{2-[2-(4-hydroxyphenyl)ethyl]oxy-2-oxoethyl}-2-[(6-O-beta-d-glucopyranosyl-beta-d-glucopyranosyl)oxy]-3,4-dihydro-2H-pyran-5-carboxylate, respectively, on the basis of NMR and MS data. Eight known compounds were identified as nuzhenide (3), GI3 (4), GI5 (5), ligstroside (6), oleoside 11-methyl ester (7), oleoside dimethyl ester (8), 1'''-O-beta-D-glucosylformoside (9), and salidroside (10). Compounds 1-9 inhibited adipocyte differentiation in 3T3-L1 cells. Dilutions of the aqueous extract of F. excelsior (1:10,000) as well as compounds 2, 3, 4, 5, and 8 activated the peroxisome proliferator-mediated receptor-alpha (PPARalpha) reporter cell system in the range of 10(-4) M, compared to 10(-7)-10(-8) M for the synthetic PPARalpha activator, WY14,643. Both biological activity profiles support the hypothesis that inhibition of adipocyte differentiation and PPARalpha-mediated mechanisms might be relevant pathways for the antidiabetic activity of F. excelsior extract.

Two new secoiridoid glycosides from the leaves of Olea europaea L

Two new secoiridoid glycosides, oleuricines A (1) and B (2), together with five known triterpenoids, beta-amyrin, oleanolic acid, erythrodiol, urs-2beta,3beta-dihydroxy-12-en-28-oic acid, and beta-maslinic acid, were isolated from the EtOAc-soluble part of EtOH extract of the leaves of Olea europaea L. The structures of these compounds were elucidated by various spectroscopic methods, including intensive 1D, 2D NMR, and HR-ESI-MS techniques.

Hemoglobin Polymerized with a Naturally Occurring Crosslinking Agent as a Blood Substitute: In Vitro and In Vivo Studies

A naturally occurring crosslinking agent, genipin, extracted from the fruits of Gardenia jasminoides ELLIS was used by our group to chemically modified biomolecules. Genipin and its related iridoid glucosides have been widely used as an antiphlogistic and cholagogue in herbal medicine. Our previous study showed that the cytotoxicity of genipin is significantly lower than glutaraldehyde. The study was to investigate the feasibility of using genipin to polymerize hemoglobin as a blood substitute. The results indicated that the rate of hemoglobin polymerization by glutaraldehyde was significantly faster than that by genipin and it readily produced polymers with molecular masses greater than 500,000 Da. It was found that the maximum degree of hemoglobin polymerization by genipin was approximately 40% if over-polymerization is to be prevented. With increasing the reaction temperature, hemoglobin concentration, and genipin-to-hemoglobin molar ratio, the duration taken to achieve the maximum degree of hemoglobin polymerization by genipin became significantly shorter. The P50 value of the unmodified hemoglobin was 9 mmHg, while that of the genipin-polymerized PLP-hemoglobin increased to 21 mmHg. It was found in a rat model that the genipin-polymerized PLP-hemoglobin resulted in a longer circulation time than the unmodified hemoglobin. In conclusion, the results of the study indicated that the genipin-polymerized hemoglobin solution has a lower oxygen affinity and a longer vascular retention time than the unmodified hemoglobin solution.

Gardenia jasminoides Ellis ethanol extract and its constituents reduce the risks of gastritis and reverse gastric lesions in rats

In this study we investigated the effects of Gardenia jasminoides Ellis (GJE) extract and its constituents, such as ursolic acid and genipin, on gastritis in rats and the growth of human gastric cancer cells. The GJE extract, ursolic acid and genipin showed the acid-neutralizing capacities, the antioxidant activities, and the inhibitory effects on the growth of Helicobacter pylori (H. pylori), which are almost equivalent to positive control compounds. In addition, the GJE extract and ursolic acid had cytotoxic activity against AGS and SUN638 gastric cancer cells. The genipin and ursolic acid inhibited significant HCl/ethanol-induced gastric lesions. Taken together, GJE extract and its constituents might have antigastritic activities, associated with the antioxidant activities, acid-neutralizing capacities, and anti-H. pylori action. Also, we could suggest that genipin and ursolic acid may be useful for the treatment and/or protection of gastritis.

Creation of macroporous calcium phosphate cements as bone substitutes by using genipin-crosslinked gelatin microspheres

Macroporous calcium phosphate cements (CPCs) were developed using genipin-crosslinked gelatin microspheres (GMs) with two weight ratios (2.5 wt% and 5 wt%). The initial setting time of the composite was prolonged by GMs. After GMs/CPCs were soaked in phosphate-buffered saline (PBS) for several weeks, macropores appeared as a result of the degradation of GMs. The presence of GMs accelerated the setting reaction and improved the structure of the composite. The compressive strength increased up to 12 MPa (2.5 wt% GMs/CPCs) and 14 MPa (5 wt% GMs/CPCs) after one week of PBS soaking, then gradually decreased to 9 MPa (2.5 wt% GMs/CPCs) and 7 MPa (5 wt% GMs/CPCs) after three weeks of soaking, and further to 6 MPa (2.5 wt% GMs/CPCs) and 2 MPa (5 wt% GMs/CPCs) after five weeks of soaking. CPCs with 2.5 wt% GMs were the most favorable composite in the tested samples. Cell experiments showed that rat osteoblasts displayed normal morphologies when exposed to the 2.5 wt% GMs/CPCs, and proliferation of the cells was also enhanced. An in vivo study showed that new bone tissue was able to grow into the pores that resulted from GM degradation. This study suggests that the new composite could be a promising candidate for use as a bone substitute under non-compression-loaded circumstances.

[Characterization and biocompatibility of human-like collagen-hyaluronic acid scaffold for blood vessel]

Human-like collagen (HLC) was cross-linked with hyaluronic acid by genipin in different ratio. The concentrations of hyaluronic acid in the mixture were 0, 0.01%, 0.05% and 0.1%. The blood vessel tubular grafts were then fabricated by freeze-drying. Microstructure, element composite, mechanical properties, cytotoxicity grade, and biocompatibility of different vascular scaffold groups were studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), tensile test, burst pressure experiment, cytotoxicity experiment, endothelial cells planted in blood vessel scaffolds and hypodermic embedding of mice. The results showed that HLC-HA (0.05%) tubular scaffold exhibited interconnected well-distributed and porous structure and porosity of 94.38%; achieved the desirable mechanical property with stress of (1000.8 +/- 7.9) kPa and burst pressure of (1058.6 +/- 8.2) kPa, hypocytotoxicity, favourable cytocompatibility, hisocompatibility and disposition of degradation.

[Effect of UCP2 activity inhibitor genipin on heart function of aging rats]

To estimate the role of uncoupling proteins in aging rat heart recovery from prolonged ischemia we used genipin application during Langendorfpreparation. It was shown that genipin in dose-depended manner depressed coronary flow, heart rate and cardiac diastolic function. Such effect was similar to that observed during myocardial Ca2+ overload by gradually elevated CaCl2, in perfusion solution. Moreover, postischemic disturbances of cardiodynamic parameters, oxygen cost of myocardial work were much increased in genipin pretreated hearts that in control ones. Thus, genipin inhibition of UCP2 activity has cardiodepressive effects that imply UCPs in cardiac calcium regulation.

[Effects of uncoupling proteins on nitric oxide synthesis and oxidative stress development in ishemia-reperfusion of old rat hearts]

Genipin is aglycone of geniposide, one of the active compounds of Gardenia gasminoides Ellis. The gardenia fruit extract has been used in traditional Chinese medicine to relieve the symptoms of type 2 diabetes that is accompanied with extensive oxidative stress and endothelial dysfunction of NO production. Besides, genipin was shown to inhibit UCP-depended proton leak through the inner mitochondrial membrane that leads to increased membrane potential and ATP production. We studied the effects of genipin at ischemia/reperfusion-induced oxidative stress and activity of NOS isozymes using Langendorfperfused old rat heart model. Ischemia/reperfusion is well-known oxidative agent, and showed significant increasing of superoxide radical, hydrogen peroxide and hydroxyl radical. Genipin application in doze 10-5 mol/L for 15 min before prolonged ischemia exerted powerful antiradical and antilipoperoxidative effects. Heart ischemia/reperfusion was supported with peroxynitrite generation and nitrozative stress. We demonstrated the inhibitory property of genipin on INOS expression that possibly occurs via protein kinase A inhibition and stabilization of I-kappaB-NF-kappaB complex. Genipin stimulated cNOS activity seemingly activating PI3K/Akt signaling pathway. Although, post-ischemic recovery ofcardiodynamic parameters of old rat hearts were depressed due to "switching off" the NO production by inducible NOS which is important in early period of reperfusion. Thus, we conclude that genipin is powerfull antioxidant and posses insulin-like activity due to its property of managing the NO production at intracellular signal transduction cascade level.

[Comparison of characteristics between glutaraldehyde- and genipin-crosslinked gelatin microspheres]

OBJECTIVE

To compare the characteristics of gelatin microspheres crosslinked by glutaraldehyde (GA) or genipin (GP).

METHODS

Gelatin microspheres, prepared by the improved emulsified cold-condensation method, were crosslinked by GP and GA, respectively. After being dispersed in PBS, two kinds of microspheres with 60% degree of cross linking were compared in terms of morphology, swelling and degrading properties. rhBMP-2 were loaded into the GP and GA microspheres, and the encapsulation rate, drug loading and releasing capacity were measured; 100%, 50% and 25% leaching liquid of GP and GA microspheres were respectively cultured with rat osteoblast (DMEM group as the control), and cell proliferation was measured by MTT method to grade the cell cytotoxicity.

RESULTS

GP and GA microspheres were both spherical with the diameters of (78 +/- 18) microm and (65 +/- 10) microm, and there were no difference between both microspheres in drug loading and encapsulation rate. But, GP microspheres, with long degrading period (28 days) compared to GA microspheres (21 days), had better dispersibility, and swelling rate (89.0% +/- 4.8%), the percentage of cumulative drug releasing at 10 days (78.80% +/- 4.96%) were both lower than GA microsphere (118.0% +/- 7.6%, 90.50% +/- 5.12%). The percentages of drug loading of GP and GA were (921 +/- 73) and (965 +/- 62) ng/g, and the encapsulation rates were 88.5% +/- 2.1% and 89.7% +/- 1.8%; showing no significant difference (P > 0.05). The cell cytotoxicity of 100%, 50% and 25% leaching liquid of GP microspheres was all at the level I, but leaching liquid of GA microspheres with corresponding concentration were at the levels of III, III and II.

CONCLUSION

GP crosslinked gelatin microspheres are superior to GA crosslinked gelatin microspheres and can be widely used in tissue engineering field.

Genipin blues: an alternative non-toxic crosslinker for heart valves?

BACKGROUND AND AIM OF THE STUDY

One approach in tissue-engineering involves the implantation of decellularized, xenogenic scaffolds, with the expectation of repopulation in vivo. However, a major limitation of this method is the propensity to induce a strong immune host response. The study aim was to mitigate this immunogenicity by employing a crosslinking treatment with genipin.

METHODS

Porcine matrices were prepared using a detergent-enzymatic treatment and fixed in 0.01% or 0.001% aqueous genipin. The mechanical properties of the matrices were monitored by tensile strength testing. The survival of chicken fibroblasts was used to determine cell-friendliness of the matrices. Non-fixed, decellularized biological scaffolds (n = 3) were implanted in a sheep model and compared to an equal number of genipin-fixed scaffolds (n = 6). Matrices implanted in the pulmonary position were explanted after six weeks and examined using light and transmission electron microscopy. The antibody reaction against porcine tissue in sheep serum was also determined.

RESULTS

Statistically significant differences were found between non-fixed leaflets, 0.001% genipin-and 0.6% glutaraldehyde (GA)-fixed leaflets for work to maximum load (non-fixed 0.00646 J; genipin-fixed 0.00509 J; GA-fixed 0.00543 J) and stiffness (non-fixed 9281 N/m; genipin-fixed 16214 N/m; GA-fixed 14401 N/m). Genipin-treated matrices were not cytotoxic. For all concentrations of genipin a high proportion of viable cells was present (79-100%). Low-dose GA (10 microg/ml) showed a distinct cytotoxicity (24.8% viability). At explant, an intense chronic inflammatory response was observed in non-fixed matrices, in contrast to genipin-fixed scaffolds. The sheep serum showed a marked decrease in IgG response in both 0.001% and 0.01% genipin-fixed matrices (IgG 30 and 20, respectively) when compared to non-fixed matrices (IgG 40).

CONCLUSION

Genipin crosslinking of the matrices attenuated, but did not eliminate, the inflammatory host reaction. Whether genipin treatment might extend the durability of xenogenic scaffolds remains to be investigated.