Lung injury caused by exposure to the gaseous fraction of exhaust from biomass combustion (cashew nut shells): a mice model.

Currently, to reduce the use of nonrenewable energy sources in energy matrices, some industries have already incorporated biomass as a source of energy for their processes. Additionally, filters are used in an attempt to retain the particulate matter present in exhaust gases. In this work, the emission gases of a cashew nut shell (CNS) combustion reactor and the deleterious effects on the respiratory system of mice exposed to gaseous fraction present in CNS emissions (GF-CNS) are analyzed. The system for CNS combustion is composed of a cylindrical stainless steel burner, and exhaust gases generated by CNS combustion were directed through a chimney to a system containing two glass fiber filters to retain all the PM present in the CNS exhaust and, posteriorly, were directed to a mice exposure chamber. The results show changes in the variables of respiratory system mechanics (G, H, CST, IC, and PV loop area) in oxidative stress (SOD, CAT, and NO2-), as well as in the histopathological analysis and lung morphometry (alveolar collapse, PMN cells, mean alveolar diameter, and BCI). Through our results, it has been demonstrated that even with the use of filters by industries for particulate material retention, special attention should still be given to the gaseous fraction that is released into the environment.

Essential oil of Croton Zehntneri attenuates lung injury in the OVA-induced asthma model.

OBJECTIVE: Croton zehntneri Pax et Hoffm. is a Euphorbiaceae species, popularly known as "canela de cunhã," a native plant of northeastern Brazil, whose essential oil (EOCZ) shows relatively specific myorelaxant action for the smooth muscle of the airways and in the respiratory tract. Based on this information, EOCZ figures as a candidate for testing in the treatment of asthma, and the present study investigated the benefits of using EOCZ in an ovalbumin-induced asthma model. METHODS: 48 male BALB/c mice were divided into six groups (n = 8). In the ST, SO100, and SO300 groups, mice were sensitized and challenged with saline, and then treated with 200 µL of 0.1% Tween 80, 100 mg/kg EOCZ and 300 mg/kg EOCZ, respectively. In the OT, OO100, and OO300 groups, mice were sensitized and challenged with OVA, and then treated with 200 µL of 0.1% Tween 80, 100 mg/kg EOCZ and 300 mg/kg EOCZ, respectively. RESULTS: Our results demonstrated significant changes in all respiratory mechanics variables analyzed between the OO300 and OT groups demonstrating the effectiveness of EOCZ to attenuate the OVA-induced lung injury. In addition, the use of EOCZ at a dose of 300 mg/kg showed an antioxidant effect and decreased inflammatory cells in the pulmonary parenchyma. In conclusion, our results demonstrated that EOCZ was able to improve the lesion in the respiratory system of mice subjected to OVA-induced asthma. CONCLUSIONS: The antioxidant action of EOCZ was likely the main mechanism of action in the reversal of this lesion, so more tests should be performed for its confirmation.

Changes of respiratory system in mice exposed to PM4.0 or TSP from exhaust gases of combustion of cashew nut shell.

Air pollution is a topic discussed all over the world and the search for alternatives to reduce it is of great interest to many researchers. The use of alternative energy sources and biofuels seems to be the environmentally safer solution. In this work, the deleterious effects on the respiratory system of mice exposed to PM4.0 or TSP, present in exhaust gases from the combustion of CNS were investigated, through data from respiratory system mechanics, oxidative stress, histopathology and morphometry of the parenchyma pulmonary. The results show changes in all variables of respiratory system mechanics, in oxidative stress, the histopathological analysis and lung morphometry. The results provide experimental support for epidemiological observations of association between effects on the respiratory system and exposure to PM4.0 or TSP from CNS combustion exhaust gases, even at acute exposure. It can serve as a basis for regulation or adjustment of environmental laws that control the emissions of these gases.

Antispasmodic effects of eugenol on rat airway smooth muscle.

This study was undertaken to assess the effects of eugenol (EUG) on tracheal muscle (TM) and the putative mechanisms underlying these effects. Cumulatively increasing concentrations (1-1000 µm) of EUG did not affect the resting tonus of TM. However, EUG (1-2000 µm) reduced the contractions induced by electrical field stimulation (IC(50) = 842.3 ± 52.7 µm), an effect that was unaltered by either 10 µm montelukast (IC(50) = 816.1 ± 70.1 µm) or 2 µm indomethacin (IC(50) = 693.1 ± 170.8 µm). EUG also completely relaxed the sustained contractile responses to 80 mM K(+) (IC(50) = 597.3 ± 60.6 µm) and 1 µm carbamoylcholine (IC(50) = 571.3 ± 148.8 µm), an effect that was unaltered by indomethacin (2 µm). Under Ca(2+) -free conditions, EUG reduced the ACh-induced contractions (IC(50) = 703.4 ± 256.1 µm), the CaCl2 -induced contractions in preparations pretreated with 60 µm ACh in the presence of nifedipine, and the Ba(2+) -induced contractions in preparations depolarized with K(+) . In tracheal preparations maintained in Ca(2+) -containing solution, EUG (300-2000 µm) relaxed the contractile response to phorbol dibutyrate (1 µm), an activator of protein kinase C. It is concluded that in TM, EUG induces a myogenic antispasmodic effect (not modulated by arachidonic acid derivatives) either through various mechanisms almost with the same pharmacological potency or via an action on a step common to all of them. These mechanisms seem to include blockade of voltage- and receptor-operated Ca(2+) channels, IP3 -induced Ca(2+) release from sarcoplasmic reticulum and reduction of the sensitivity of contractile proteins to Ca(2+) .