Effects of the led therapy on the global DNA methylation and the expression of Dnmt1 and Dnmt3a genes in a rat model of skin wound healing.

The use of light emitting diodes (LED) as a therapeutic resource for wound healing has increased over the last years; however, little is still known about the molecular pathways associated to LED exposure. In the present study, we verified the effects of LED therapy on DNA methylation and expression of the DNA methyltransferase (Dnmt) genes, Dnmt1 and Dnmt3a, in an in vivo model of epithelial wound healing. Male Wistar rats were submitted to epithelial excision in the dorsal region and subsequently distributed within the experimental groups: group 1, animals that received irradiation of 0.8 J/cm(2) of LED (604 nm); group 2, animals that received 1.6 J/cm(2) of LED (604 nm); control (CTL), animals not submitted to therapeutic intervention. LED applications were performed during 7 days, and tissues from the periphery of the wound area were obtained for molecular analysis. The Image-J software was used for analysis of the wound area. DNA methylation was evaluated by ELISA-based method and gene expressions were quantified by real-time PCR. Decrease on global DNA methylation profile was observed in all experimental groups (CTL, 1, and 2) revealing the participation of DNA methylation in the healing process. Significant decrease in the wound area accompanied by increase in the Dnmt3a expression was associated to group 2. Based on our findings, we propose that DNA methylation is an important molecular mechanism associated to wound healing and that irradiation with 1.6 J/cm(2) of LED evokes an increase in the expression of the Dnmt3a that might associates to the efficiency of the epithelial wound healing.

Noradrenaline microinjected into the dorsal periaqueductal gray matter causes anxiolytic-like effects in rats tested in the elevated T-maze.

AIMS: The dorsal periaqueductal gray matter (dPAG) is involved in the integration of behavioral and cardiovascular responses caused by fear and anxiety situations. Some studies suggest an involvement of noradrenergic neurotransmission in the dPAG in anxiety modulation, however, there is no evidence about its role in panic attacks. The goal of this work was to study the effect of NA microinjection in dPAG in rats submitted to the elevated T-maze (ETM). MATERIALS AND METHODS: Male Wistar had a cannula implanted in the PAG where it was injected NA in the doses of 1, 3, 15, 45nmol/50nl or artificial cerebrospinal fluid previous the ETM test. KEY FINDINGS: NA intra-dPAG decreased inhibitory avoidance behavior in the ETM without changing escape, indicating only an anxiolytic-like effect. Furthermore, the microinjection of NA did not change the general exploratory activity of the animals submitted to the open field test, suggesting that the anxiolytic-like effect is not due to an increase in exploratory activity. SIGNIFICANCE: The results indicate an involvement of noradrenergic neurotransmission in the dPAG in defensive reactions associated with generalized anxiety, but not as main mechanisms for the panic, in rats submitted to the elevated T-maze providing support for other research aimed at improving the treatment of generalized anxiety.