The Japanese Journal of Dysphagia Rehabilitation
Online ISSN : 2434-2254
Print ISSN : 1343-8441
Original Paper
Effects of Pulmonary Aspiration of Barium Sulfate or Various Gelling Agents for Jelly Foods on Lung Tissue and Pulmonary Function in Rats
―A Study of Pulmonary Aspiration Model in Rats―
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2009 Volume 13 Issue 3 Pages 176-182


As the elderly population grows, dysphagia patients are increasing due to cerebrovascular diseases. These patients often use jelly foods for recovering swallowing function but have a high risk of aspiration. However, there have been few studies on the influence of jelly food aspiration.

The aim of this study was to investigate the functional and histopathologic effects on lung function of different gelling agents for jelly foods (gelatin, carrageenan, and agar) and barium sulfate after pulmonary aspiration in rats. Male SD rats were randomly assigned to one of five groups (n=5 per group). After anesthesia induction by inhalation of isoflurane, rats were intubated endotracheally with a 16-gauge angiocatheter and test samples (saline solution [0.9%], barium sulfate [contract media], gelatin jelly, carrageenan jelly, and agar jelly) were injected into the lung through the trachea in a dose of 0.1 ml/kg to induce aspiration. After 2 days, the rats were sacrificed and tissue samples from the trachea to the lungs were taken for histological examinations. Blood samples were also taken to measure parameters such as pH, pO2, and pCO2. Then, the rheological properties of the jelly samples were measured at 10, 20, 30, and 37℃ using a rheometer.

With the aspiration of barium sulfate, inflammation reaction in the lungs was slight and pulmonary gas change function (blood pH, pO2, and pCO2) was not affected. These results suggested that barium sulfate is relatively safe in terms of aspiration at the dose employed in this study.

In the aspiration of various jelly samples, alveolar histiocytes were statistically higher in the agar or carrageenan jelly than in the saline. Lipid-laden alveolar macrophages were significantly higher in the agar or carrageenan jelly than in the saline. The gel stiffness of jelly was decreased as temperature increased, and gelatin jelly melted completely to liquid at near the body temperature of 37℃. Blood pH, pO2, and pCO2 remained unchanged after pulmonary aspiration of each jelly. These data suggested that pulmonary aspiration of jelly does not affect lung function at the dose employed in the study.

Based on the results, we concluded that lung tissue damages such as inflammation reaction occurring after pulmonary aspiration of jelly depend on the viscosity of jelly at near body temperature, and hence the choice of suitable training food is important for direct therapy of dysphagia patients.

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© 2009 The Japanese Society of Dysphagia Rehabilitation
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