Rumi Ueha1, Nogah Nativ-Zeltzer2, Taku Sato3, Takao Goto3, Akihito Yamauchi3, Peter C Belafsky2, Tatsuya Yamasoba3. 1. Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-8655, Japan. ruu1025@yahoo.co.jp. 2. Department of Otolaryngology, The University of California, Davis, Sacramento, CA, USA. 3. Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-8655, Japan.
Abstract
PURPOSE: Barium sulfate (Ba) suspension is the most widely used contrast agent for upper gastrointestinal and videofluoroscopic swallow studies (VFSS). The effect of Ba concentration on lung injury is uncertain. The aims of this study were to explore the effects of different barium concentrations on the respiratory organs and elucidate the underlying mechanisms of these effects in an established animal model of aspiration. METHODS: Animal model study. Eight-week-old male Sprague-Dawley rats were allocated into three groups (n = 12, each group). Two groups underwent tracheal instillation of low (30% w/v) and high (60% w/v) concentration Ba (low-Ba, high-Ba). A control group was instilled with saline. Half of the animals were euthanized on day 2 and the remaining half were euthanized on day 30. Histological and gene analyses were performed. RESULTS: Both low-Ba and high-Ba aspiration caused inflammatory cell infiltration in the lung at 2 days post aspiration with an increase in the expression of inflammatory cytokines. At 30 days post aspiration, small quantities of barium particles remained in the lung of the low-Ba group without any inflammatory reaction. Chronic inflammation was recognized in the high-Ba group up to 30 days post aspiration. CONCLUSION: A small amount of high concentration Ba (60% w/v) caused sustained inflammation in the rat lung at least 30 days after aspiration. Even with a small amount of low concentration Ba aspiration (30% w/v), Ba particles can remain in the lung over a month, causing sustained late effects.
PURPOSE:Barium sulfate (Ba) suspension is the most widely used contrast agent for upper gastrointestinal and videofluoroscopic swallow studies (VFSS). The effect of Ba concentration on lung injury is uncertain. The aims of this study were to explore the effects of different barium concentrations on the respiratory organs and elucidate the underlying mechanisms of these effects in an established animal model of aspiration. METHODS: Animal model study. Eight-week-old male Sprague-Dawley rats were allocated into three groups (n = 12, each group). Two groups underwent tracheal instillation of low (30% w/v) and high (60% w/v) concentration Ba (low-Ba, high-Ba). A control group was instilled with saline. Half of the animals were euthanized on day 2 and the remaining half were euthanized on day 30. Histological and gene analyses were performed. RESULTS: Both low-Ba and high-Ba aspiration caused inflammatory cell infiltration in the lung at 2 days post aspiration with an increase in the expression of inflammatory cytokines. At 30 days post aspiration, small quantities of barium particles remained in the lung of the low-Ba group without any inflammatory reaction. Chronic inflammation was recognized in the high-Ba group up to 30 days post aspiration. CONCLUSION: A small amount of high concentration Ba (60% w/v) caused sustained inflammation in the rat lung at least 30 days after aspiration. Even with a small amount of low concentration Ba aspiration (30% w/v), Ba particles can remain in the lung over a month, causing sustained late effects.