Effects of multiple pulmonary aspirations of enteral solutions on lung tissue damage

The effect of methylene blue treatment on aspiration pneumonia

BACKGROUND

The study aimed to examine whether methylene blue (MB) prevents different pulmonary aspiration materials-induced lung injury in rats.

METHODS

The experiments were designed in 60 Sprague-Dawley rats, ranging in weight from 250-300 g, randomly allotted into one of six groups (n = 10): saline control, Biosorb Energy Plus (BIO), hydrochloric acid (HCl), saline + MB treated, BIO + MB treated, and HCl + MB treated. Saline, BIO, and HCl were injected into the lungs in a volume of 2 mL/kg. After surgical procedure, MB was administered intraperitoneally for 7 days at a daily dose of 2 mg/kg per day. Seven days later, rats were killed, and both lungs in all groups were examined biochemically and histopathologically.

RESULTS

Our findings show that MB inhibits the inflammatory response reducing significantly (P < 0.05) peribronchial inflammatory cell infiltration, alveolar septal infiltration, alveolar edema, alveolar exudate, alveolar histiocytes, interstitial fibrosis, granuloma, and necrosis formation in different pulmonary aspiration models. Pulmonary aspiration significantly increased the tissue hydroxyproline content, malondialdehyde levels, and decreased (P < 0.05) the antioxidant enzyme (superoxide dismutase and glutathione peroxidase) activities. MB treatment significantly (P < 0.05) decreased the elevated tissue hydroxyproline content and malondialdehyde levels and prevented the inhibition of superoxide dismutase and glutathione peroxidase (P < 0.05) enzymes in the tissues. Furthermore, there is a significant reduction in the activity of inducible nitric oxide synthase (iNOS), terminal deoxynucleotidyl transferase dUTP nick end labeling, and arise in the expression of surfactant protein D in lung tissue of different pulmonary aspiration models with MB therapy.

CONCLUSIONS

MB treatment might be beneficial in lung injury and therefore shows potential for clinical use.

The effect of hyperbaric oxygen treatment on aspiration pneumonia

We have studied whether hyperbaric oxygen (HBO) prevents different pulmonary aspiration materials-induced lung injury in rats. The experiments were designed in 60 Sprague-Dawley rats, ranging in weight from 250 to 300 g, randomly allotted into one of six groups (n = 10): saline control, Biosorb Energy Plus (BIO), hydrochloric acid (HCl), saline + HBO treated, BIO + HBO treated, and HCl + HBO treated. Saline, BIO, HCl were injected into the lungs in a volume of 2 ml/kg. A total of seven HBO sessions were performed at 2,4 atm 100% oxygen for 90 min at 6-h intervals. Seven days later, rats were sacrificed, and both lungs in all groups were examined biochemically and histopathologically. Our findings show that HBO inhibits the inflammatory response reducing significantly (P < 0.05) peribronchial inflammatory cell infiltration, alveolar septal infiltration, alveolar edema, alveolar exudate, alveolar histiocytes, interstitial fibrosis, granuloma, and necrosis formation in different pulmonary aspiration models. Pulmonar aspiration significantly increased the tissue HP content, malondialdehyde (MDA) levels and decreased (P < 0.05) the antioxidant enzyme (SOD, GSH-Px) activities. HBO treatment significantly (P < 0.05) decreased the elevated tissue HP content, and MDA levels and prevented inhibition of SOD, and GSH-Px (P < 0.05) enzymes in the tissues. Furthermore, there is a significant reduction in the activity of inducible nitric oxide synthase, TUNEL and arise in the expression of surfactant protein D in lung tissue of different pulmonary aspiration models with HBO therapy. It was concluded that HBO treatment might be beneficial in lung injury, therefore, shows potential for clinical use.

Effects of Nigella sativa seed extract on ameliorating lung tissue damage in rats after experimental pulmonary aspirations

Aspiration of gastric contents can cause serious lung injury, although the mechanisms of pulmonary damage are still not clear and means of amelioration of the pulmonary damage have been little investigated. The black cumin seed, Nigella sativa L. (NS) has been shown to have specific health benefits and the aim of the current study was to investigate the possible beneficial effects of NS on experimental lung injury in male Wistar rats after pulmonary aspiration of different materials. The rats were randomly allotted into one of six experimental groups (n=7 per group): (1) saline control, (2) saline+NS treated, (3) Pulmocare (a specialized nutritional supplement given to pulmonary patients), (4) Pulmocare+NS treated, (5) hydrochloric acid, (6) hydrochloric acid+NS treated. The saline, Pulmocare and hydrochloric acid were injected into the lungs in a volume of 2 ml/kg. The rats received daily oral doses of NS volatile oil (400mg/kg body weight) by means of intragastric intubation for 7 days starting immediately after the pulmonary aspiration of the materials. After 7 days, the rats were sacrificed and tissue samples from both lungs were taken for histopathological investigation. To date, no similar study investigating the potential for NS treatment to protect against lung injury after pulmonary aspiration of materials has been reported. Our study showed that NS treatment inhibits the inflammatory pulmonary responses, reducing significantly (p<0.05) peribronchial inflammatory cell infiltration, alveolar septal infiltration, alveolar edema, alveolar exudate, alveolar macrophages, interstitial fibrosis, granuloma and necrosis formation in different pulmonary aspiration models. Our data indicate a significant reduction in the activity of inducible nitric oxide synthase (iNOS) and a rise in surfactant protein D in lung tissue of different pulmonary aspiration models after NS therapy. Based on our results, we conclude that NS treatment might be beneficial in lung injury and have potential clinical use.