MicroRNA-126 upregulation, induced by training, plays a role in controlling microcirculation in dexamethasone treated rats.

Microcirculation maintenance is associated with microRNAs. Nevertheless, the role of microRNAs induced by training in preventing dexamethasone (DEX)-induced microvascular rarefaction remains unknown. The study aim was to investigate if training-induced microRNAs are able to improve microcirculation proteins and prevent DEX-induced microvascular rarefaction. Rats underwent training for 8 weeks and then were treated with DEX (50 µg/kg per day, s.c.) for 14 days. Arterial pressure was measured and tibialis anterior (TA) muscle was collected for analyses. DEX induced hypertension concomitantly with capillary density loss (CD, -23.9%) and decrease of VEGF (-43.0%), p-AKT/AKT (-39.6%) and Bcl-2 (-23.0%) and an increase in caspase-3-cleaved protein level (+34.0%) in TA muscle. Training upregulated microRNA-126 expression (+13.1%), prevented VEGF (+61.4%), p-AKT/AKT (+37.7%), Bcl-2 (+7.7%) decrease and caspase-3-cleaved (-23.1%) increase associated with CD (+54.7%) reduction and hypertension prevention. MiRNA-126 upregulation, induced by training, plays a role in controlling microcirculation, which may be a potential target against DEX-induced microvascular rarefaction.

The effectiveness of glass ionomer cement as a fiber post cementation system in endodontically treated teeth.

This study compared the performance of a glass ionomer (GC Gold Label 1, GIC) as a fiber post cementation system for glass fiber posts with a self-adhesive resin cement (Relyx U200, RUC) and a conventional resin cement system (Scotchbond Muli-Purpose and Relyx ARC, RAC). Thirty endodontically treated canines were randomly divided in three groups (n = 10), according to the fiber post cementation system: (RAC)-Scotchbond Multi-Purpose and Relyx X ARC; (RUC)-Relyx U200 and (GIC)-GC Gold Label 1 Luting & Lining. Rhodamine was incorporated into the cementation system prior to the fiber post cementation. After glass fiber post cementation, roots were incubated in artificial saliva for 6 months. After that, specimens from the cervical, middle, and apical thirds of the post space were prepared and analyzed using a push-out bond strength test and confocal laser microscopy. ANOVA one way and Tukey tests showed that GIC and RUC demonstrated similar push-out bond strength values, independently of the post space third (p > .05); however, values were greater than those shown by RAC (p < .05). For dentin penetrability, GIC and RUC also had similar results (p > 0.05) and lower than RAC (p < 0.05). Inside the root canal, the cementation system using glass ionomer cement (GC Gold Label 1 Luting & Lining) has similar push-out bond strength to the self-adhesive resin cement (Relyx U200) and these were higher than the conventional resin (Relyx ARC), despite its higher dentin penetrability.

Exercise training attenuates dexamethasone-induced hypertension by improving autonomic balance to the heart, sympathetic vascular modulation and skeletal muscle microcirculation.

OBJECTIVE: Although aerobic exercise training has been recommended as nonpharmacological treatment of high blood pressure, the mechanisms of training-induced blood pressure lowering effects in dexamethasone (DEX)-induced hypertension remain unclear. Therefore, the aim of this study was to investigate the preventive role of exercise training in counteracting DEX-induced hypertension. METHODS: Rats were submitted to aerobic exercise training for 8 weeks or kept sedentary and then treated with DEX (50 µg/kg/day, s.c.) or saline injections for 14 days. Thereafter, all rats underwent carotid artery catheterization, and cardiovascular autonomic modulation was evaluated by spectral analysis. In addition, soleus muscle was collected for morphometric and protein level analysis. RESULTS: DEX treatment increased arterial pressure concomitantly with an increase in low-frequency spectral power of systolic arterial pressure and low frequency in pulse interval (94.11 and 58.58%, respectively), and a decrease in high-frequency spectral power of pulse interval (-12.05%). Capillary density (-25.87%), capillary-to-fibers ratio (-21.22%), vascular endothelial growth factor level (-15.10%), B-cell lymphoma 2 (Bcl-2) level (-16.40%) and Bcl-2/Bcl-2 associated X protein ratio (-27.14%) were all decreased after DEX treatment. Exercise training attenuated DEX-induced increase in arterial pressure accompanied by an attenuation of low-frequency spectral power of systolic arterial pressure, low frequency in pulse interval increases and high-frequency spectral power of pulse interval decrease. Training also prevented the decrease in capillary density (+44.43%), capillary-to-fibers ratio (+36.97%), vascular endothelial growth factor (+16.46%), Bcl-2 (+15.21%) protein level and Bcl-2/Bcl-2-associated X protein ratio (+30.93%). CONCLUSION: These results demonstrate that exercise training improves cardiovascular autonomic balance to the heart associated with an improvement in sympathetic modulation of vascular tone and microcirculatory function in the skeletal muscle of DEX-induced hypertensive rats.