Effect of Metalloproteinase Inhibitors on the Microtensile Bond Strength of Composite Resin to Er: YAG Laser-Irradiated Dentin

Abstract This study evaluated the effect of matrix metalloproteinase (MMP) inhibitors - 2% (CHX) and sodium fluoride (NaF) (5000 ppm) - on microtensile bond strength (μTBS) of composite resin to Er:YAG laser-irradiated dentin after chemical degradation of the bond interface. The occlusal surface of forty sound human molars was removed exposing the dentin surface (n=10), which was polished, irradiated with Er:YAG laser, acid etched and dried. Twenty specimens were rewetted with 2% CHX (control group) and 20 were rewetted with NaF (5000 ppm). The adhesive system was applied and a 4-mm-high plateau of light-cured composite resin was built up. Resin-dentin sticks were obtained with a rectangular cross-sectional area (0.8-1 mm2) and were either stored in water at 37 ?#61616;C for 24 h or submitted to chemical degradation. For chemical degradation, they were immersed in 10% NaOCl aqueous solution for 5 h and rinsed in water for 1 h. The sticks were submitted to microtensile test in a mechanical testing machine at 0.5 mm/min until failure. Fracture pattern was analyzed using SEM. μTBS values were calculated in MPa and submitted to analysis of variance ANOVA (α=0.05). The variance analysis showed that the 'MMP inhibitor' and 'degradation' factors (p=0.214 and p=0.093, respectively) and interaction between the factors were not statistically significant (p=0.143). Mixed failure predominated in all groups. In conclusion, the 2% CHX and NaF 5000 ppm presented similar μTBS of composite resin to laser-irradiated dentin before and after chemical degradation.

Resumo Este estudo avaliou o efeito dos inibidores de metaloproteinase, clorexidina 2% e fluoreto de sódio (5000 ppm), na resistência de união entre a dentina irradiada por laser Er:YAG e a resina composta após a degradação química da interface de união. A superfície oclusal de quarenta molares humanos hígidos (n=10) foi removida expondo uma superfície de dentina, que foi polida, irradiada com laser Er:YAG, condicionada com ácido e seca. Vinte espécimes foram re-umedecidos com clorexidina 2% (Grupo controle) e 20 com fluoreto de sódio (5000 ppm). O sistema adesivo foi aplicado e um platô de resina composta fotopolimerizável de 4 mm de altura foi construído. Palitos de resina-dentina foram obtidos com secção transversal retangular (0,8-1 mm2). Eles foram armazenados em água (24 h a 37 ?#61616;C) ou submetidos a degradação química. Para a degradação química, foram imersos em solução aquosa de hipoclorito de sódio a 10% durante 5 horas e lavados em água durante 1 h. Os palitos foram submetidos ao teste de microtração em uma máquina de ensaios mecânicos a 0,5 mm/min até a fratura. O padrão de fratura foi analisado em MEV. Os valores de resistência de união foram calculados em MPa e submetidos à análise de variância ANOVA (α=0,05). A análise de variância mostrou que os fatores inibidor de metaloproteinases e degradação (p=0,214 e p=0,093, respectivamente), e a interação entre os fatores não foram estatisticamente significantes (p=0,143). A predominância de falha mista foi detectada para todos os grupos. Em conclusão, a clorexidina a 2% e fluoreto de sódio (ppm 5000) apresentaram resistência de união entre dentina irradiada e resina composta semelhante antes e após a degradação química.

Effects of metoclopramide on the expression of metalloproteinases and interleukins in left colonic anastomoses. An experimental study

PURPOSE : To evaluate the effects of metoclopramide on metalloproteinases (MMP) and interleukins (IL) gene expression in colonic anastomoses in rats. METHODS : Eighty rats were divided into two groups for euthanasia on the 3rd or 7th postoperative day (POD), then into two subgroups for sepsis induction or not, and then into subgroups to receive either metoclopramide or saline solution. Left colonic anastomosis were performed and then analyzed. RESULTS : On the 3rd POD, metoclopramide was associated with increased expression of MMP-1a, MMP-13, and TNF-α. On the 7th POD, the transcripts of all MMPs, TNF-α, IL-1β, IFN-γ, and IL-10 of the treated animals became negatively modulated. In the presence of sepsis, metoclopramide did not change MMPs and decreased IL-6, IL-1β, IFN-γ and IL-10 gene expression on the 3rd POD. On the 7th POD, increased expression of all MMPs, IFN-γ and IL-10 and negative modulated TNF-α and IL-6 gene expression. CONCLUSION : Administration of metoclopramide increased metalloproteinases and interleukins gene expression on the 3rd postoperative day and negatively modulated them on the 7th POD. In the presence of abdominal sepsis, metoclopramide did not change MMPs and decreased ILs gene expression on the 3rd POD. On the 7th POD, the drug increased expression of all MMPs.

Effect of human follicular fluid on implantation of mouse embryo

Prevention of implantation is considered as one of the suitable methods for contraception or interception. Therefore during this study the effect of human follicular fluid [FF] on mouse implantation was evaluated. The results obtained during this study show that FF contains enzymes and upon incubation with mouse uterine tissue, results in delimitation of epithelium. This effect was inhibited by heat inactivation or addition of EDTA to FF. In vivo uterine wash with follicular fluid on days 3,4,5 and 6-post mating prevents implantation and therefore significantly reduces implantation and pregnancy rate. However uterine wash on day 7 post mating with FF had no effect on implantation and pregnancy rate. On day 3,4,5,6 and 7 with Ham's 10 as control had no effect on implantation or pregnancy rate. Addition of EDTA also prevented the in vivo effect of FF, suggesting that the active agent present in FF is likely to be a metalloprotoinase which inactivates with heat and addition of EDTA. Taking into consideration the fact that FF does not affect the pregnancy of the next cycles, thus the FF or its active agent can be considered as good interceptive agent for prevention of pregnancy rate

Actividad de las metaloproteinasas en el miocardio de ratas sometidas a endotoxina y su inhibición con doxiciclina / Metalloproteinase activity in myocardium of rats exposed to endotoxin: its inhibition with doxycycline

Background: The ventricular dysfunction of endotoxic shock could be secondary to the activity of myocardial metalloproteinases that degrade collagenous matrix. Metalloproteinase activity can be inhibited with doxycycline in some tissues. Aim: To study if the effect of endotoxemia on myocardial metalloproteinase activity can be inhibited with doxycycline. Material and methods: Left ventricular metalloproteinase activity was studied in four groups of rats. Group 1 received intraperitoneal dextrose in water, group 2 received 8 mg/kg intraperitoneal E coli endotoxin, group 3 received 60 mg/kg/day doxycycline for three days and group 4 received doxycycline and E coli endotoxin. Enzymatic activity was measured by Western Blot and zymography. Results: Zymography showed a higher metalloproteinase 2 (49 percent) and 9 (100 percent) activity in rats treated with endotoxin, when compared with control rats. In group 4, doxycycline reduced the activity of metalloproteinases 2 and 9 by 71 percent and 63 percent respectively, as compared with group 3. Western blot showed a 50 percent increase in the expression of metalloproteinase 1 in rats treated with endotoxin, that was reduced by 64 percent with the use of doxycycline. Conclusions: Endotoxin administration increases myocardial metalloproteinases and doxycyclin inhibits this activation. Therefore, doxycyclin could reduce the degradation of myocardial fibrillar collagen and ventricular dysfunction of endotoxic shock

Actividad de metaloproteinasas de arterias y venas y su regulación mediante doxiciclina / Metalloproteinase activity of arteries and veins and it regulation through doxycicline

Segments of internal mammary arteries and saphenous veins and cultured smooth muscle cells were incubated with and without doxycicline. Metalloproteinases activity was assessed by zymography and Western Blot. Activity of Metalloproteinase-9 in saphenous veins was 217 percent less than in internal mammary arteries. In these vessels doxycicline decreased metalloproteinase-9 activity by 207 percent and metalloproteinase-1 expression. In cultured smooth muscle cells, the median inhibitory concentration of doxycicline for metalloproteinase-2 was 138 uM (r2=0.82). Internal mammary arteries and saphenous veins have different metalloproteinase activities, that are inhibited by doxycicline