Browsing by Author "Freitas, Diamantino"
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- Effects of high-intensity infrasound on liver lipid content of ratsPublication . Pereira, Gonçalo Martins; Pereira, Sofia S.; Santos, Madalena; Brito, José; Freitas, Diamantino; Carvalho, António Oliveira de; Águas, Artur; Oliveira, Maria João; Oliveira, PedroPrevious experimental studies show that exposure to noise with high and audible frequencies causes multiple metabolic alterations, such as increased liver glycogen and triglycerides. However, the effect of exposure to sound with lower frequencies, such as high-intensity infrasound (frequency <20 Hz and sound pressure level >90 dB), on the liver lipid content is still unclear. As such, we aimed to study the effect of exposure to high-intensity infrasound of both normal and glucose intolerant rats on the liver lipid content. For this study, 79 wild-type male Wistar rats were randomly divided into two groups: G1, no treatment, and G2, induced glucose intolerance. Each of these two groups was randomly divided in two subgroups: s (animals kept in silence) and i (animals continuously exposed to high-intensity infrasound noise). At three noise-exposure time-points (1, 6 and 12 weeks) the rats were sacrificed, the liver was excised and hepatic lipids extracted. Data analysis was performed using a two-way ANOVA (p = 0.05). No significant effects due to interactions between the several factors exist on the liver lipid content (p=0.077). Moreover, no significant effects due to infrasound exposure (p=0.407) or glucose tolerance status (p=0.938) were observed. Our study shows that continuous exposure to high-intensity infrasound has no influence on the lipid content of the liver of both normal and glucose intolerant animals. This finding reinforces the need for further experimental studies on the physiological effects of infrasound due to its possible hazardous effects on human health.
- Infrasound exposure promotes development of atrial fibrosis in ratsPublication . Lousinha, Ana; Oliveira, Maria João R.; Borrecho, Gonçalo; Brito, José; Oliveira, Pedro; Pereira, Gonçalo; Carvalho, António Oliveira de; Freitas, Diamantino; Águas, Artur P.; Antunes, Eduardo
- Infrasound induces coronary perivascular fibrosis in ratsPublication . Lousinha, Ana; Oliveira, Maria João R.; Borrecho, Gonçalo; Brito, José; Oliveira, Pedro; Carvalho, António Oliveira de; Freitas, Diamantino; Águas, Artur P.; Antunes, EduardoBACKGROUND: Chronic exposure to industrial noise is known to affect biological systems, namely, by inducing fibrosis in the absence of inflammatory cells. In rat hearts exposed to this environmental hazard, we have previously found myocardial and perivascular fibrosis. The acoustic spectrum of industrial environments is particularly rich in high-intensity infrasound (<20 Hz), whose effects on the heart are unknown. We evaluated the morphological changes induced by IFS in rat coronaries in the presence and absence of dexamethasone. METHODS: Adult Wistar rats were divided into three groups: group A (GA)-IFS (<20 Hz, 120 dB)-exposed rats for 28 days treated with dexamethasone; group B (GB)-IFS-exposed rats; group C (GC)-age-matched controls. The midventricle was prepared for observation with an optical microscope using 100× magnification. Thirty-one arterial vessels were selected (GA 8, GB 10, GC 13). The vessel caliber, thickness of the wall, and perivascular dimensions were quantified using image J software. Mann-Whitney and Kruskal-Wallis tests were used to compare the groups for lumen-to-vessel wall (L/W) and vessel wall-to-perivascular tissue (W/P) ratios. RESULTS: IFS-exposed rats exhibited a prominent perivascular tissue. The median L/W and median W/P ratios were 0.54 and 0.48, 0.66 and 0.49, and 0.71 and 0.68, respectively, in GA, GB, and GC. The W/P ratio was significantly higher in GC compared with IFS-exposed animals (P=.001). The difference was significant between GC and GB (P=.008) but not between GC and GA. CONCLUSION: IFS induces coronary perivascular fibrosis that differs under treatment with corticosteroid.