Smoke affects lung growth, gene expression
Doctors and scientists have known for years that cigarette smoke has a range of damaging effects on the human body. In adults, excessive smoking can cause emphysema, a condition in which the lungs become rigid and brittle.
Babies and young children are particularly susceptible to the effects of second-hand smoke.
A team of Hopkins researchers led by Sharon McGrath-Morrow, a lung specialist from Hopkins Hospital, observed the effects of cigarette smoke in newborn mice to quantify its effects.
In the study, two groups of mice were exposed to cigarette smoke: newborn mice and their mothers, and six-week old mice. Some subjects in both groups were comprised the control group, but the rest were exposed to cigarette smoke for two weeks.
During the first week of the study, the mice were exposed to one hour of cigarette smoke per day. This time increased to two hours per day during the second week of the study.
Two weeks in mice is comparable to about two years in humans, so the study's results would be relevant to newborn babies and infants.
At the end of the two weeks, all the eight-week old mice and half the two-week old mice were sacrificed for observation. The other half of the two-week old mice were sacrificed when they turned eight-weeks old to look at the long-term effects of early exposure.
Lung growth was obviously impaired in mice exposed to smoke. Lungs mostly grow after birth, especially in the first two years of life for humans, but continue growing through adolescence.
Alveoli, little sacs inside the lung where the exchange of gas into the bloodstream occurs, are the most crucial part of the lung; these are the most susceptible to damage caused by cigarette smoke.
In the study, it was observed that the number of alveoli in the eight-week old mice was modestly lower than in a healthy mouse. Alveoli are the site of oxygen absorption in the lungs, so a decreased number of alveoli can cause hypoxia, or low oxygen levels in the blood.
Babies and young children are particularly susceptible to the effects of second-hand smoke.
A team of Hopkins researchers led by Sharon McGrath-Morrow, a lung specialist from Hopkins Hospital, observed the effects of cigarette smoke in newborn mice to quantify its effects.
In the study, two groups of mice were exposed to cigarette smoke: newborn mice and their mothers, and six-week old mice. Some subjects in both groups were comprised the control group, but the rest were exposed to cigarette smoke for two weeks.
During the first week of the study, the mice were exposed to one hour of cigarette smoke per day. This time increased to two hours per day during the second week of the study.
Two weeks in mice is comparable to about two years in humans, so the study's results would be relevant to newborn babies and infants.
At the end of the two weeks, all the eight-week old mice and half the two-week old mice were sacrificed for observation. The other half of the two-week old mice were sacrificed when they turned eight-weeks old to look at the long-term effects of early exposure.
Lung growth was obviously impaired in mice exposed to smoke. Lungs mostly grow after birth, especially in the first two years of life for humans, but continue growing through adolescence.
Alveoli, little sacs inside the lung where the exchange of gas into the bloodstream occurs, are the most crucial part of the lung; these are the most susceptible to damage caused by cigarette smoke.
In the study, it was observed that the number of alveoli in the eight-week old mice was modestly lower than in a healthy mouse. Alveoli are the site of oxygen absorption in the lungs, so a decreased number of alveoli can cause hypoxia, or low oxygen levels in the blood.
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Phil
posted 4/18/08 @ 1:04 PM EST
Someone should show this to the people who are still spreading around old tobacco company propaganda. I still see links to sites that claim that exposure to secondhand smoke has some sort of "protective" affect on kids. (Continued…)
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