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CHANGES IN COMPLEX CARBOHYDRATE CONTENT AND STRUCTURE IN RAT LUNGS CAUSED BY PROLONGED OZONE INHALATION
Impact/Purpose:
Ozone is formed when emissions from mobile and industrial sources react in the presence of sunlight. It is a highly reactive gas, and the major component of urban smog. Because inhaling ozone affects lung function in humans, the U.S. Environmental Protection Agency has set a National Ambient Air Quality Standard (NAAQS) for this pollutant. The current NAAQS is 0.12 parts per million (ppm); compliance requires that this level not be exceeded for more than one hour, once per year.
Because of ozone's reactive nature, prolonged or repeated exposure to ozone is thought to be a potential risk factor for lung cancer. This concern prompted the National Toxicology Program (NTP) to conduct a bioassay of prolonged exposure to evaluate ozone's carcinogenicity in rats and mice. Another concern is that long-term exposure to ozone may injure the tissues of the respiratory tract, and lead to the development or exacerbation of chronic lung diseases such as fibrosis and emphysema. To examine this hypothesis, the NTP allotted additional animals to investigators funded by the Health Effects Institute to study noncancerous alterations in lung tissue, structure, and function that are characteristic of chronic lung diseases.
One characteristic of the early stages of chemically induced fibrosis and emphysema in laboratory animals is an increase in the level of complex carbohydrates (a heterogeneous group of carbohydrate-containing polymers) in lung connective tissue. Connective tissue is important because it confers mechanical strength to the lungs by providing a supporting framework for cells; however, increased connective tissue can distort normal lung structure and decrease the lung's efficiency for gas exchange. The study of the effects of long-term ozone exposure on lung complex carbohydrates, described in this report, was one of eight laboratory studies supported by the NTP/HEI collaborative agreement. In addition to stu
Ozone is formed when emissions from mobile and industrial sources react in the presence of sunlight. It is a highly reactive gas, and the major component of urban smog. Because inhaling ozone affects lung function in humans, the U.S. Environmental Protection Agency has set a National Ambient Air Quality Standard (NAAQS) for this pollutant. The current NAAQS is 0.12 parts per million (ppm); compliance requires that this level not be exceeded for more than one hour, once per year.
Because of ozone's reactive nature, prolonged or repeated exposure to ozone is thought to be a potential risk factor for lung cancer. This concern prompted the National Toxicology Program (NTP) to conduct a bioassay of prolonged exposure to evaluate ozone's carcinogenicity in rats and mice. Another concern is that long-term exposure to ozone may injure the tissues of the respiratory tract, and lead to the development or exacerbation of chronic lung diseases such as fibrosis and emphysema. To examine this hypothesis, the NTP allotted additional animals to investigators funded by the Health Effects Institute to study noncancerous alterations in lung tissue, structure, and function that are characteristic of chronic lung diseases.
One characteristic of the early stages of chemically induced fibrosis and emphysema in laboratory animals is an increase in the level of complex carbohydrates (a heterogeneous group of carbohydrate-containing polymers) in lung connective tissue. Connective tissue is important because it confers mechanical strength to the lungs by providing a supporting framework for cells; however, increased connective tissue can distort normal lung structure and decrease the lung's efficiency for gas exchange. The study of the effects of long-term ozone exposure on lung complex carbohydrates, described in this report, was one of eight laboratory studies supported by the NTP/HEI collaborative agreement. In addition to st
Description:
EPA GRANT NUMBER: R828112C065III
Title: Changes in Complex Carbohydrate Content and Structure in Rat Lungs Caused by Prolonged Ozone Inhalation
Investigator: Bhandaru Radhakrishnamurthy
Institution: Tulane University of Louisiana
EPA Project Officer: Stacey Katz
Project Period: April 1, 2000 - March 31, 2005
Project Amount: $0
RFA: Health Effects Institute
Research Category: Health Effects
Description
Objective:Ozone is formed when emissions from mobile and industrial sources react in the presence of sunlight. It is a highly reactive gas, and the major component of urban smog. Because inhaling ozone affects lung function in humans, the U.S. Environmental Protection Agency has set a National Ambient Air Quality Standard (NAAQS) for this pollutant. The current NAAQS is 0.12 parts per million (ppm); compliance requires that this level not be exceeded for more than one hour, once per year.
Because of ozone's reactive nature, prolonged or repeated exposure to ozone is thought to be a potential risk factor for lung cancer. This concern prompted the National Toxicology Program (NTP) to conduct a bioassay of prolonged exposure to evaluate ozone's carcinogenicity in rats and mice. Another concern is that long-term exposure to ozone may injure the tissues of the respiratory tract, and lead to the development or exacerbation of chronic lung diseases such as fibrosis and emphysema. To examine this hypothesis, the NTP allotted additional animals to investigators funded by the Health Effects Institute to study noncancerous alterations in lung tissue, structure, and function that are characteristic of chronic lung diseases.
One characteristic of the early stages of chemically induced fibrosis and emphysema in laboratory animals is an increase in the level of complex carbohydrates (a heterogeneous group of carbohydrate-containing polymers) in lung connective tissue. Connective tissue is important because it confers mechanical strength to the lungs by providing a supporting framework for cells; however, increased connective tissue can distort normal lung structure and decrease the lung's efficiency for gas exchange. The study of the effects of long-term ozone exposure on lung complex carbohydrates, described in this report, was one of eight laboratory studies supported by the NTP/HEI collaborative agreement. In addition to stu
dying lung and nasal structure and function, investigators studied other constituents of lung connective tissue.
Approach:Dr. Bhandaru Radhakrishnamurthy used standard biochemical methods to measure changes in the content, structure, and function of complex carbohydrates in lung tissue from male and female rats exposed to 0, 0.12, 0.5, and 1.0 ppm ozone for 20 months.
Supplemental Keywords: Air, ambient air quality, air toxics, epidemiology, health effects, particulate matter, human health risk assessment, mobile sources, ozone, inhalation studies, animal models, disease, cumulative effects., Scientific Discipline, RFA, Toxicology, Risk Assessments, Disease & Cumulative Effects, Biochemistry, Environmental Chemistry, exposure and effects, inhalation toxicology, environmental health effects, effects of ozone in the lung, lung content, lung inflammation, lung injury, emissions, automobiles, air pollutants, human health effects, particulates, engines, ambient particle health effects, motor vehicles, air pollution, airway disease, inhalability, inhaled, lung disease, carbohydrate content of lungs, PM, human exposure, particulate exposure, lung structure