Proanthocyanidin Group Research Articles

Proanthocyanidins protects 3-NPA-induced ovarian function decline by activating SESTRIN2-NRF2-mediated oxidative stress in mice

Abnormal apoptosis of ovarian cells caused by oxidative stress is an important cause of premature ovarian failure (POF). Previous studies revealed that proanthocyanidins (PCs) are powerful natural antioxidants that can safely prevent oxidative damage in humans. However, the protective effect and mechanism of PCs on ovarian function during the course of POF remain unknown. In this study, female mice were injected with 3-nitropropionic acid (3-NPA) to establish an ovarian oxidative stress model; at the same time, the mice were treated with PC via gavage. Thereafter, the expression of various apoptosis genes, hormones, and related molecules was assessed. Compared with those in the control group, the ovarian index, follicle count at all levels, expression of MVH, PCNA and BCL2, and estradiol (E2) and progesterone (P) levels were significantly lower in the POF group, but significant recovery was observed in terms of MVH and PCNA expression and E2 and P levels in the POF + PCs group. The apoptosis marker genes BAX and ROS were significantly increased in the POF group but were notably restored in the POF + PCs group. In addition, the expression of Sestrin2, an antiapoptotic protein, was significantly increased in the PCs treatment group, as were the upstream and downstream regulatory factors NRF2 and SOD2, and the indices of the Sestrin2 overexpression group were similar to those of the PCs treatment group. In summary, these findings suggest that PCs have potential as innovative therapeutic agents for preventing and treating POF by activating the protective SESTRIN2-NRF2 pathway against oxidative stress.

Effects on dentin nanomechanical properties, cell viability and dentin wettability of a novel plant-derived biomodification monomer

ObjectivesTo evaluate the effects of dentin biomodification agents (Proanthocyanidin (PAC), Cardol (CD) and Cardol-methacrylate (CDMA) on dentin hydrophilicity by contact angle measurement, viability of dental pulp stem cells (DPSCs) and nanomechanical properties of the hybrid layer (HL). MethodsCDMA monomer was synthesized from cardol through methacrylic acid esterification. Human extracted third molars were used for all experiments. For nanomechanical tests, specimens were divided in four groups according to the primer solutions (CD, CDMA, PAC and control) were applied before adhesive and composite coating. Nanomechanical properties of the HL were analyzed by nanoindentation test using a Berkovich probe in a nanoindenter. Wettability test was performed on dentin surfaces after 1 min biomodification and measured by contact angle analysis. Cytotoxicity was assessed by a MTT assay with DPSCs after 48 and 72 h. Data were analyzed with Student's t test or Two-way ANOVA and Tukey HSD test (p < 0.05). ResultsCD and CDMA solutions achieved greater hydrophobicity and increased the water-surface contact angles when compared to PAC and control groups (p < 0.05). PAC group showed a greater reduction of elastic modulus in nanoindentation experiments when compared to CD and CDMA groups (p < 0.05) after 4 months of aging. CD inhibited cell proliferation compared to all further materials (p < 0.05), whilst CDMA and PAC indicated no cell cytotoxicity to human DPSCs. SignificanceCardol-methacrylate provided significantly higher hydrophobicity to dentin and demonstrated remarkable potential as collagen crosslinking, attaining the lowest decrease of HL’s mechanical properties. Furthermore, such monomer did not affect pulp cytotoxicity, thereby highlighting promising feasibility for clinical applications.

The Effect of "Proanthocyanidin" on Ischemia-Reperfusion Injury in Skeletal Muscles of Rats.

Background and Objectives: Lower limb skeletal muscle ischemia-reperfusion (IR) injury is associated with increased morbidity and mortality, and it is common in several clinical situations such as aortic aneurysms repairment, peripheral arterial surgery, vascular injury repairment, and shock. Although it is generally accepted that oxidative stress mediators have a significant role in IR injury, its precise mechanism is still unknown. Anecdotally, it is sustained not only by structural and functional changes in the organ it affects but also by damage to distant organs. The purpose of this report is to illustrate the effect of proanthocyanidin on IR injury. Materials and Methods: In our study, 18 male Wistar albino rats were used. The subjects were divided into three groups containing six mice each (control, C; ischemia-reperfusion, IR; ischemia-reperfusion and proanthocyanidin; IR-PRO). Intraperitoneal proanthocyanidin was given to the IR and proanthocyanidin groups 30 min before laparotomy, and 1 h ischemia led to these two groups. After one hour, reperfusion started. Muscle atrophy-hypertrophy, muscle degeneration-congestion, fragmentation-hyalinization, muscle oval-central nucleus ratio, leukocyte cell infiltration, catalase enzyme activity, and TBARS were all examined in lower-limb muscle samples after one hour of reperfusion. Results: When skeletal muscle samples were evaluated histopathologically, it was discovered that muscle atrophy-hypertrophy, muscle degeneration-congestion, fragmentation-hyalinization, and leukocyte cell infiltration with oval-central nucleus standardization were significantly higher in the IR group than in the C and IR-P groups. Oval-central nucleus standardization was significantly higher in the IR and IR-PRO groups than in the control group. TBARS levels were significantly higher in the IR group than in the control and IR-PRO groups, while catalase enzyme activity was found to be significantly lower in the IR group than in the control and IR-PRO groups. Conclusions: As a consequence of our research, we discovered that proanthocyanidins administered before IR have a protective impact on skeletal muscle in rats. Further research in this area is required.

Study of proanthocyanidin promotes osteogenic differentiation of human periodontal ligament stem cells through the transcription factor EB-induced autophagy-lysosome pathway

Objective: To investigate the mechanism of proanthocyanidin (PA) in regulating the osteogenic differentiation of human periodontal ligament stem cells (PDLSCs), and to explore the effects of PA on the expression and nuclear translocation of transcription factor EB (TFEB) and on the autophagy-lysosome pathway. Methods: PDLSCs were divided into control group and PA group, which were subjected to RNA sequencing analysis (RNA Seq) to detect differentially expressed genes. The osteogenic differentiation ability and autophagy level were observed by real-time fluorescence quantitative PCR (RT-qPCR) analysis, alkaline phosphatase (ALP) staining and transmission electron microscope (TEM), respectively. Scratch assay and Transwell assay were used to detect the migration ability of PDLSCs. Lysotracker and immunofluorescence staining were used to detect the biogenesis of lysosomes. The total protein expression of transcription factor EB (TFEB) as well as that in cytoplasm and nucleus were detected by Western blotting. Confocal laser scanning microscope (CLSM) was used to observe the nuclear translocation of TFEB. The PDLSCs were treated with small interfering RNA (siRNA) technology to knock down the expression levels of TFEB gene with or without PA treatment. Western blotting was used to analyze the expressions of autophagy-related proteins Beclin1 and microtubule-associated protein 1 light chain 3 (LC3B), as well as osteogenic-related proteins runt-related transcription factor 2 (RUNX2), ALP, and osteocalcin in PDLSCs. Results: Compared with the control group, the osteogenic-related and autophagy-related genes showed differential expression in PDLSCs after PA treatment (P<0.05). The mRNA expression levels of osteogenic-related genes RUNX2 (2.32±0.15) and collagen type Ⅰ alpha 1 (COL1α1) (1.80±0.18), as well as the autophagy related genes LC3B (1.87±0.08) and Beclin1 (1.63±0.08) were significantly increased in the PA group, compared with the control group (1.01±0.16, 1.00±0.10, 1.00±0.07, 1.00±0.06, respectively, all P<0.01). Compared with the control group, the PA group had higher ALP activity, and more autophagosomes and autophagolysosomes observed by TEM. PA promoted the migration of PDLSCs (P<0.05) and the increased number of lysosomes and the expression of lysosomal associated membrane protein 1 (LAMP1). In the PA group, the relative expression level of total TFEB protein (1.49±0.07) and the nuclear/cytoplasmic expression of TFEB protein (1.52±0.12) were significantly higher than the control group (1.00±0.11, 1.00±0.13, respectively) (t=6.43, P<0.01; t=5.07, P<0.01). The relative nuclear/cytoplasmic fluorescence intensity of TFEB in the PA group (0.79±0.09) was increased compared with the control group (0.11±0.08) (t=8.32, P<0.01). Knocking down TFEB significantly reduced the expression of TFEB (1.00±0.15 vs 0.64±0.04), LAMP1 (1.00±0.10 vs 0.69±0.09), Beclin1 (1.00±0.05 vs 0.60±0.05), and LC3B Ⅱ/Ⅰ (1.00±0.06 vs 0.73±0.07) in PDLSCs (P<0.05, P<0.05, P<0.01, P<0.01). When TFEB gene was knocked down, the expression levels of Beclin1 (1.05±0.11), LC3B Ⅱ/Ⅰ (1.02±0.09), RUNX2 (1.04±0.10), ALP (1.04±0.16), and osteocalcin (1.03±0.15) proteins were significantly decreased in the PA group compared with the pre-knockdown period (1.28±0.03, 1.44±0.11, 1.38±0.11, 1.62±0.11, 1.65±0.17, respectively) (P<0.05, P<0.01, P<0.05, P<0.01, and P<0.01, respectively). Conclusions: PA promotes the osteogenic differentiation of PDLSCs through inducing the expression and nuclear translocation of TFEB and activating the autophagy-lysosome pathway.

Randomized clinical trial of non-antibiotic prophylaxis with d-Mannose plus Proanthocyanidins vs. Proanthocyanidins alone for urinary tract infections and asymptomatic bacteriuria in de novo kidney transplant recipients: The Manotras study

BackgroundStudies analyzing non-antibiotic alternatives in kidney transplant UTI's are lacking. d-Mannose, a simple sugar, inhibits bacterial attachment to the urothelium, as does Proanthocyanidins; both could act as a synergic strategy preventing UTI; nonetheless their efficacy and safety have not been evaluated in kidney transplant population yet. MethodsThis is a pilot prospective, double-blind randomized trial. Sixty de novo kidney transplant recipients were randomized (1:1) to receive a prophylactic strategy based on a 24-h prolonged release formulation of d-Mannose plus Proanthocyanidins vs. Proanthocyanidins (PAC) alone. The supplements were taken for the first 3 months after kidney transplant and then followed up for 3 months as well. The main objective of the study was to search if the addition of Mannose to PAC alone reduced the incidence of UTI and/or asymptomatic bacteriuria in the first 6 months post-transplantation. Results27% of patients experienced one UTI episode (cystitis or pyelonephritis) while asymptomatic bacteriuria was very common (57%). Incidences according UTI type or AB were: 7% vs. 4% for cystitis episode (p 0.3), 4% vs. 5% for pyelonephritis (p 0.5) and 17% vs. 14% for asymptomatic bacteriuria (p 0.4) for patients in the Mannose+PAC group vs. PAC group respectively. The most frequent bacteria isolated in both groups was Escherichia coli (28% of all episodes), UTI or AB due to E. coli was not different according to study group (30% vs. 23% for Mannose+PAC vs. PAC alone p 0.37). ConclusionsNon-antibiotic therapy is an unmet need to prevent UTI after kidney transplantation; however, the use of d-Mannose plus PAC does not seem capable to prevent it.

Polyphenols Can Improve Resin-Dentin Bond Durability by Promoting Amorphous Calcium Phosphate Nanoparticles to Backfill the Dentin Matrix.

To investigate the effects of proanthocyanidins (PA), myricetin, resveratrol, and kaempferol on the modification of dentin collagen and the inhibition of matrix metalloproteinase (MMP) activity, and to evaluate their contributions to the biomimetic remineralization and resin-dentin bonding performance. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and in situ zymography were applied to verify the collagen modification and MMP activity inhibition induced by these four polyphenols. Scanning electron microscopy/energy dispersive spectrometer (SEM/EDS) analysis, X-ray diffraction (XRD), ATR-FTIR, Vickers hardness numbers (VHN), and micro-computed tomography (micro-CT) were performed to characterize the remineralized dentin. Microtensile bond strength (μTBS) and nanoleakage were investigated to evaluate the effects of the four polyphenols on resin-dentin bonding durability. ATR-FTIR and in situ zymography confirmed that these four polyphenols could modify dentin collagen and inhibit MMP activity, respectively. Chemoanalytic characterization exhibited the efficacies of the four polyphenols in promoting dentin biomimetic remineralization. The surface hardness of PA-pretreated dentin was the greatest. Micro-CT results demonstrated that the PAs group possessed the highest amount of dentin surface minerals and the lowest amount of deep-layer minerals. The surface and deep-layer mineral contents of the Myr group were higher than Res and Kae groups. Treatment with these four polyphenols significantly increased the initial μTBS compared with the control group without primer conditioning. μTBS decreased significantly during aging, and the decrease was more severe in the PAs and Kae groups than in the Myr and Res groups. With or without aging, the polyphenol groups exhibited relatively less fluorescence. However, the Myr and Res groups showed less serious nanoleakage after aging. PA, myricetin, resveratrol, and kaempferol can modify dentin collagen, inhibit MMP activity, promote biomimetic remineralization, and improve resin-dentin bond durability. Compared with PA and kaempferol, myricetin and resveratrol are more effective in improving resin-dentin bonding.

Biocompatible Films of Collagen-Procyanidin for Wound Healing Applications.

The study investigated the effect of polyphenols present in Cassia auriculata (CA) leaves in enhancing the stability of the collagen protein and the wound healing potential of collagen films. The crude ethanol extract of CA was analyzed for the presence of phytochemicals and purified by column chromatography using solvents with increasing polarity. The ethanol eluted active fractions (EEAF) that precipitated gelatin was characterized using HP-TLC, FTIR spectroscopy, ESI-FT-MS/MS, and 1H NMR spectroscopy. The active compound was identified to be procyanidin B belonging to the proanthocyanidins group. The wound healing property of EEAF and collagen type I extracted from Clarias batrachus fish skin and the bovine tendon was assessed by in vitro scratch assay on L929 mice fibroblast cell lines. The EEAF-treated collagen coating enhanced in vitro wound closure in comparison with the uncoated dish. It was observed that EEAF treatment improved the physical strength of collagen films. The in vivo wound healing of the EEAF-treated collagen film was examined in male Wister rats and the wound site tissues were assessed. In vivo wound examination showed enhanced healing with EEAF incorporated collagen films. Comparatively, the EEAF-treated bovine tendon collagen films showed improved physical properties and better wound healing property than fish collagen films.

The effect of natural reducing agents on push-out bond strength of AH plus and BioRoot RCS to sodium hypochlorite treated root dentin.

Aims:To evaluate the effect of natural anticoagulants 6.5% proanthocyanidin (PA) and 25% bamboo salt on push-out bond strength (PBS) of AH Plus and BioRoot RCS to dentin.Subjects and Methods:30 single-rooted extracted human teeth were collected. After establishing the working length samples were prepared up to size F3. 5 ml of 3% NaOCl was used as irrigant during instrumentation followed by rinse with 5 ml of 17% ethylenediaminetetraacetic acid. Samples were randomly divided into groups based on the final irrigation solution: Group I – AH plus sealer group, Ia – Saline group, Ib – PA group, Ic – Bamboo salt (BS) group. Group II – BioRoot RCS group, IIa – Saline group, IIb – PA group, IIc – BS group. After obturation, samples were embedded in self-cure acrylic resin and 2 mm thick root slices were made at coronal middle and apical 3rd. These slices were subjected to PBS testing followed by stereomicroscopic examination for checking the mode of failure.Statistical Analysis Used:Kruskal–Wallis and Dunn's post hoc test.Results:3% NaOCl significantly decreased the bond strength of AH Plus as compared to BioRoot RCS to dentin (P < 0.05). Both PA and BS were capable of increasing the PBS of AH Plus and BioRoot RCS to NaOCl-treated dentin.Conclusions:Final irrigation with antioxidants such as PA and BS eliminates the risk of reduced bond strength of sealer to root canal walls, which ensues following the use of NaOCl as an irrigant.

The effect of proanthocyanidin and casein phosphopeptide-amorphous calcium phosphate on the bond strength durability to caries-affected dentin.

ObjectivesThe aim of this study was to evaluate the effect of proanthocyanidin (PA) and casein phosphopeptide‐amorphous calcium phosphate (CPP‐ACP) paste on the micro‐shear bond strength (μSBS) durability of an etch‐and‐rinse adhesive to caries‐affected dentin (CAD).Materials and methodsThe occlusal surfaces of 80 human molars with occlusal caries were ground to expose flat dentin surfaces with CAD. Then, they were randomly divided into four groups (n = 20) according to the CAD pretreatment. The study groups included no pretreatment, pretreatment with CPP‐ACP for 3 min, pretreatment with PA for 1 min, and pretreatment with PA for 1 min followed by CPP‐ACP for 3 min before adhesive application. After restoring the specimens with composite resin, μSBS testing was performed for half of the bonded surfaces in each group after 24 h and the other half was tested after 6 months of water storage and failure mode analysis was performed.ResultsThe PA group was associated with a higher μSBS than the control and CPP‐ACP groups after 24 hours (p < 0.05). No significant difference was observed regarding the μSBS of the control and the other groups after 24 h (p > 0.05). No significant difference was observed regarding the μSBS of the PA and PA + CPP‐ACP groups (p > 0.05). The μSBS of the 6‐month specimens was significantly lower than those of the 24‐h specimens for all the groups (p < 0.05) except for the PA group which did not exhibit a significant difference between the two times (p > 0.05). The most common type of failure was mixed failure.ConclusionPA pretreatment could stabilize the CAD‐resin interface and protect degradation over time. The same effect was not observed for CPP‐ACP or PA + CPP‐ACP.

Effects of Dietary Proanthocyanidins Supplementation on Growth Performance, Digestive Enzymes Activities and Microbiota in the Intestine of Juvenile American Eels (Anguilla rostrata) Cultured in Cement Tanks

This trial was conducted to investigate the effects of proanthocyanidins (PACs) on the growth performance, digestive enzymes activities and microbiota in the intestines of juvenile American eels (Anguilla rostrata) cultured in cement tanks. Six cement tanks stocked with similar fish size and weight (about 120 g/fish and 2116 kg/tank) were randomly divided into a control group fed with a commercial diet and a PACs group fed with a commercial diet supplemented 400 mg/kg PACs, with three replicates in each group. The trial period lasted 60 days. The finial fish weight and weight gain rate were significantly improved by PACs supplementation (P&lt;0.05). There were no significant differences in feed efficiency and feeding rate between the control group and PACs group (P&gt;0.05). Activities of protease in intestines were significantly enhanced by PACs supplementation (P&lt;0.05), however dietary PACs supplementation had no significant effect on the activities of amylase and lipase (P&gt;0.05). Furthermore, dietary PACs supplementation increased the richness and decrease the diversity of intestinal microbiota. At the phylum level, the higher relative abundance of Proteobacteria and the lower relative abundances of Firmicutes and Actinobacteria were found in PACs group compared to control group. At the genus level, PACs supplemented in diet significantly increased the relative abundances of Candidatus Arthromitus, Paracoccus and Eubacterium hallii (P&gt;0.05). In conclusion, dietary 400 mg/kg PACs supplementation improved growth performance and activity of protease in intestine, and modulate intestinal microbiota of juvenile American eel cultured in cement tanks.

The antibiofilm and collagen-stabilizing effects of proanthocyanidin as an auxiliary endodontic irrigant.

To evaluate the antibiofilm effect of proanthocyanidin (PA) solution as an irrigant against Enterococcus faecalis (E.faecalis) and its influence on the mechanical properties and biodegradation resistance of demineralized root dentine. Enterococcus faecalis were introduced into human root dentine tubules by a serial centrifugation method and grown for 1week. Dentine blocks infected with 1-week-old E.faecalis biofilms were treated with the following irrigants: sterile water (control), 2% chlorhexidine (CHX), 2% PA, 5% PA and 10% PA. After treatment, the live and dead bacteria proportions within E.faecalis biofilms were analysed using confocal laser scanning microscopy. To evaluate the biostability of fully demineralized dentine treated by the aforementioned irrigants, the elastic modulus and hydroxyproline release of human dentine incubated in collagenase solution were tested at baseline, after irrigant treatment and after biodegradation, respectively. Furthermore, the surface chemical bond of demineralized dentine collagen treated by various irrigants was characterized by X-ray photoelectron spectroscopy (XPS). Statistical analysis was performed using one-way anova and Tukey's post hoc multiple comparisons with the significance level at 5%. The proportion of dead E.faecalis volume was significantly higher in the PA and CHX groups than that in the control group (P<0.05). PA irrigation significantly increased the mechanical properties of demineralized dentine (P<0.05), and the effect was enhanced with increasing PA concentration. CHX and PA groups had significantly less elasticity loss and hydroxyproline release (P<0.05). The biomodification of dentine collagen by PA was verified by increased C-O/C-N peak percentage under C1s and C-O peak percentage under O1s narrow-scan XPS spectra. Proanthocyanidin killed E.faecalis within biofilms and enhanced the biostability of the collagen matrix of demineralized root dentine. It might be used as an auxiliary endodontic irrigant with antibiofilm and collagen-stabilizing effects.

Protective effects of oligomeric proanthocyanidins in mice exposed to paraquat

Objective: To investigate the protective effect of oligomeric proanthocyanidins (OPCs) in paraquat-exposed mice. Methods: An acute lung injury model was established by a single intraperitoneal injection of paraquat (PQ) in BALB/c mice. The mice were randomized into control group, paraquat-exposed group (PQ group) , oligomeric proanthocyanidins group (OPCs group) , and paraquat and oligomeric proanthocyanidins-exposed group (PQ+OPCs group) , with 10 mice in each group. Only normal saline was intraperitoneally injected into the mice in the control group. The mice in the PQ group were divided into 8 subgroups according to the dose of poison administered, i.e., 0, 25, 50, 75, 100, 150, 200, and 300 mg/kg; the mice in each subgroup were given a single intraperitoneal injection of PQ and were observed and recorded for death at 3, 6, 12, 24, 36, 48, 60, 84, and 96 hours after PQ injection. Origin 8.0 was used to calculate the median lethal dose (LD(50)) of the mice at 24, 36, 48, and 60 hours after PQ injection, and the PQ dose (100 mg/kg, ip) was chosen based on the accumulated mortality rate. An OPCs-treated experimental model was established by an intraperitoneal injection of OPCs followed by a single PQ injection (100 mg/kg, ip) 1 hour later to observe the effects of OPCs on the apparent poisoning effect and fatality rate in PQ-induced mice. Immunohistochemistry was used to determine the effect of OPCs on PQ-induced lung tissue lesions. The peripheral blood samples of the mice were collected to determine the effects of OPCs on PQ-induced inflammatory factors such as tumor necrosis factor-α (TNF-α) , interleukine-1β (IL-1β) , and transforming growth factor-β1 (TGF-β1) using enzyme-linked immunosorbent assay. Results: The mortality rate was significantly correlated with the dose and exposure time in PQ-exposed mice; the mortality rate gradually increased with increasing dose and exposure time of the poison (P<0.05) . The LD(50) values for the mice were 216.67, 124.11, and 71.24 mg/kg at 24, 48, and 72 hours after PQ exposure, respectively. PQ could induce animal death at 12 hours after injection, and the mortality rate of the animals was 40% (4/10) at 48 hours after PQ exposure. The PQ-induced mortality rate of the mice in the PQ+OPCs group was reduced, and the mortality rate of the animals was 10% (1/10) at 48 hours after PQ exposure. Compared with treatment in the control group, OPCs exposure alone had no significant effect on the expression of TNF-α and TGF-β1 in the peripheral blood (P>0.05) , but it significantly inhibited the expression of IL-1β (P<0.05) . After 48 hours, the expression of TNF-α, TGF-β1, and IL-1β in peripheral blood significantly increased by 39%, 45%, and 38%, respectively, in the PQ group (P<0.05) , but they significantly decreased by 31%, 13%, and 22%, respectively, in the OPCs+PQ group as compared with the PQ group (P<0.05) . Conclusion: OPCs pretreatment can significantly alleviate PQ-induced poisoning effect.

Relative abundances of novel cyclic prodelphinidins in wine depending on the grape variety.

The identification of cyclic B-type procyanidins in grape and wine was recently disclosed. Some of these were also found in berries of totally different vegetal species (eg, Vaccinium sp.). However, presence of a wider class of these cyclic condensed tannin compounds with variably substituted monomers has never been addressed so far. Here, an extended list of oligomeric cyclic proanthocyanidins (PAC) bearing variable substitution patterns on the main flavan-3-ol unit has been searched in wines. Nearly 7600 theoretical structures were calculated and searched in red and white wine samples made from different grape varieties. Moreover, a hydrogen/deuterium exchange approach (already applied to a cyclic tetrameric procyanidin) coupled to high-resolution mass spectrometry was applied to confirm their cyclic B-type structure rather than a non cyclic A-type structure, otherwise isomeric and undistinguishable by LC-MS alone. The main group of novel cyclic PAC observed is shown to contain (epi)gallocatechin beside (epi)catechin as the constituent monomers.

Effect of collagen cross-linkers on micro tensile bond strength of total-etch adhesive to dentin

Purpose: To evaluate the efficiency of collagen cross-linkers on micro-tensile bond strength of total-etch adhesive with and without thermal cycling. Materials and methods: The occlusal surfaces of twenty-four caries-free permanent human molars were ground flat to obtain a uniform surface free of enamel exposing the mid thickness of dentine. The prepared speciemens were randomly divided into four equal test groups according to the type of dentin pretreatment (n=6). Group I; control group: the exposed dentin did not receive additional treatment after acid etching. Group II; the etched dentin was treated with Gluma Desensitizer(GA). Group III; the specimens surface was painted with 5% glutaraldhyde solution (GD). Group IV; the specimen surface was painted with 15% proanthocyanidin (PA). Single Bond Universal adhesive was applied to the dentin surface of all the test groups and the dentin specimens were restored with resin composite. The specimens were sectioned to obtain beams of 0.9±0.1 mm in thickness and 5.5±1 mm in length and half of the resultant beams of each group were subjected to thermo cycling. Tensile load was applied until bonding failure of the specimen occurred and micro tensile bond strength was calculated in Mega Pascal. Comparison between all test groups was done using One Way ANOVA followed with Tukey’s post hoc test when the ANOVA test was significant. p value was ≤0.5. Comparison between the thermocycled and none thermocycled groups was done using unpaired student t test. Results: The highest statistically significant microtensile bond strength values were found in the Gluma and GD surface pretreated groups, with no statistical significant difference between them. The lower micro tensile bond strength values were found in the control and PA groups with no significant difference between them, while thermocycling did not decrease the microtensile strength values of the PA group.Conclusions:1-Gluma and glutaraldehyde used as cross-linkers increased the microtensile bond strength of dental adhesive to dentin and maintain collagen stability with thermocycling. 2-The PA cross-linkers did not improve microtensile bond strength but maintain bond stability with thermocycling increasing the longevity of the adhesive bond.

Evaluation of 5% proanthocyanidin and 30% alpha-tocopherol on shear bond strength of composite to bleached enamel: An In vitro study

Objective: The aim of this in vitro study is to evaluate and compare the effect of 5% proanthocyanidin and 30% alpha-tocopherol on the bond strength of composite resin to the bleached enamel. Materials and Methods: The labial enamel surface of sixty central incisors was flattened for the purpose of this study. Fifteen teeth served as control group which did not receive bleaching nor antioxidant treatment. The remaining 45 teeth then were randomly divided into three groups of 15 each. They are Group 1: bleaching with 38% hydrogen peroxide for 10 min without the use of antioxidant, Group 2: bleaching followed by treating with 5% proanthocyanidin, and Group 3: bleaching followed by treating with 30% alpha-tocopherol. The bonded specimens were stored in distilled water (37°C, 24 h) and tested for shear bond strength in a universal testing machine. The data were analyzed with one-way ANOVA and Tukey's post hoc test. Results: Higher bond strength values were seen in the control group followed by 5% proanthocyanidin group. Conclusion: Use of 5% proanthocyanidin can effectively reverse the bond strength of bleached enamel.

Therapeutic effects of proanthocyanidin and coenzyme Q10 on nitrogen mustard-induced ocular injury.

Nitrogen mustard (NM) is a devastating casualty agent in chemical warfare. There is no effective antidote to treat NM-induced ocular injury. We aimed to assess the effects of proanthocyanidin (PAC) and coenzyme Q10 (CoQ10) on NM-induced ocular injury. Eighteen male rats were divided into the following 4 groups: NM, NM + PAC, NM + CoQ10, and control. The 3 NM groups received a single dose of NM (0.02 mg/μL) on the right eye to induce ocular injury. The control group received saline only. Thirty minutes after the application of NM, the NM + PAC group received PAC (100 mg/kg) via gastric gavage, while the NM + CoQ10 group received CoQ10 (10 mg/kg) via intraperitoneal injection. PAC and CoQ10 were administered once a day for 5 consecutive days. The rats were then sacrificed. Macroscopic images of the eyes were examined and eye tissues were collected for histology. The treatment groups were compared to the control group with regard to both corneal opacity and lid injury scores. The findings were not significantly different for both the NM + PAC and NM + CoQ10 groups. In both the NM + PAC and NM + CoQ10 groups, the histological changes seen in the NM group demonstrated improvement. Our results indicate that PAC and CoQ10 treatments have therapeutic effects on NM-induced ocular injury in a rat model. PAC and CoQ10 may be novel options in patients with NM-induced ocular injury.

Protective effects of proanthocyanidins against cadmium-induced testicular injury through the modification of Nrf2-Keap1 signal path in rats

The purpose of this study was to evaluate the potential chemoprotective effects of proanthocyanidins (PAs) against cadmium (Cd)-induced oxidative damage of testes via Nrf2-Keap1 signal pathway in rats. Briefly, by using biochemical histological analysis, as well as the real time PCR and western blot approach, oxidative damage in rat testicular tissue was observed after exposure to Cd. In addition, significant down-regulations of mRNA and protein levels of nuclear erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1), γ-glutamyl cysteine synthetase (γ-GCS), glutathione peroxidase (GSH-Px) and quinone oxidoreductase 1 (NQO1), as well as a significant up-regulation of Kelch sample related protein-1 (Keap1) levels in testicular tissue were observed after Cd exposure. Notably, these alterations were reverted back to near normalcy in Cd+PAs group rats. In conclusion, PAs exhibited a significant chemopreventive potential against Cd-induced testicular oxidative damage in rats, possibly through the modification of Nrf2-Keap1 signal path.

The effect of two cross-linking agents on dentin bond strength of resin-modified glass ionomer.

Objectives:The hybrid layer at the interface of resin-modified glass ionomer cements and dentin is prone to degradation by endogenous matrix metalloproteinases. We aimed to investigate the effect of two types of collagen crosslinkers, carbodiimide and proanthocyanidin (PA), on immediate and medium-term bond strength of a resin-modified glass ionomer to dentin.Materials and Methods:Seventy-two molars were flattened on the occlusal surface to expose dentin. The specimens were divided into control, 1-ethyl-3-(3-dimethylaminopropy) carbodiimide hydrochloride (EDC), and PA groups (n = 24). In the EDC and PA groups, carbodiimide and PA solutions were applied for 1 min, respectively. Resin-modified glass ionomer was bonded. Half of the specimens in each group were tested for shear bond strength after 24 h and the other half were tested after 6 months.Statistical Analysis:Data were analyzed with SPSS version 16 (SPSS Inc, Chicago, IL, USA), using two-way ANOVA, and subgroup analysis was performed using one-way ANOVA, Tukey's test, and t-test.Results:Two-way ANOVA showed that treatment and time affected the bond strength. Carbodiimide and PA did not affect the immediate bond strength (P = 0.51). After 6 months, the bond strength of the EDC group was significantly lower than that of the control and PA groups. Bond strength of the control and PA groups increased after 6 months (P ≤ 0.002).Conclusion:PA did not interfere with maturation of RMGIC unlike carbodiimide. Therefore, it can be suggested as an matrix metalloproteinase inhibitor before bonding of resin-modified glass ionomer to dentin.

Proanthocyanidins Attenuation of H2O2-Induced Oxidative Damage in Tendon-Derived Stem Cells via Upregulating Nrf-2 Signaling Pathway.

Proanthocyanidins (PCs) have shown inhibition of oxidative damage by improving Nrf-2 expression in many tissues. However, the cytoprotective effects of PCs on H2O2-induced tendon damage have not been verified. The current study was aimed at assessing the cytoprotection of PCs on the oxidative cellular toxicity of tendon-derived stem cells (TDSCs) induced by H2O2. The TDSCs were isolated from patellar tendons of Sprague Dawley (SD) rats, and the cells after third passage were used for subsequent experiments. The isolated cells were identified by flow cytometry assay and multidifferentiation potential assay. Cell Counting Kit-8 assay was performed to examine cell viability. Real-Time PCR and Western Blot were employed to, respectively, assess the mRNA and protein expressions of Nrf-2, GCLM, NQO-1, and HO-1. PCs significantly improved the cell viability of TDSCs. Furthermore, H2O2 upregulated Nrf-2, GCLM, NQO-1, and HO-1 without significant difference, while the proteins expressions were increased with significant difference in PCs group and PCs + H2O2 cotreated group. All the findings indicated that PCs could protect against the oxidative damage induced by H2O2 in TDSCs, and the cytoprotective effects might be due to the ability of PCs to activate the expressions of GCLM, HO-1, and NQO-1 via upregulating Nrf-2 signaling pathway.

Degradation of dentin-bonded interfaces treated with collagen cross-linking agents in a cariogenic oral environment: An in situ study

ObjectivesTo evaluate the effect of treatment using collagen cross-linking agents as primer on resin–dentin bond interfaces subjected to cariogenic oral environment (COE). MethodsEach of forty human teeth had two cavities (4×4×1.5mm) prepared within enamel margins. These cavities were acid-etched and treated by the primers containing one of the following treatment agents (6.5% proanthocyanidins, 0.1% riboflavin-UVA activated light, 5% glutaraldehyde or distilled water as a control group). After that the cavities were bonded and restored with resin composite. One restoration for each tooth was tested immediately (IM) and another was included in an intra-oral palatal device that was placed in each mouth of ten adult volunteers for 14 days in COE. After 14 days, the teeth were removed and each restoration was sectioned to obtain a slice for Knoop microhardness (KHN) and resin–dentin bonded sticks for microtensile bond strength (μTBS) and nanoleakage (NL) evaluation. Data were evaluated by two-way ANOVA and Tukey’s tests (α=0.05). ResultsAfter 14days in a COE, the KHN was reduced for all groups, except for the glutaraldehyde group; however, the proanthocyanidins group retained the highest KHN in IM and after COE (p<0.05). The μTBS was not reduced after COE for the proanthocyanidins and glutaraldehyde groups, however only the proanthocyanidins treatment did not increase the NL after COE (p>0.05). ConclusionThe in situ study model seems to be a suitable short-term methodology to investigate the degradation of the bonding interfaces under a more realistic condition. Under COE, the proanthocyanidins and glutaraldehyde treatments produced stable interfaces that are worth further clinical investigation.