Feeding tomato juice to mice kept them from developing emphysema after cigarette smoke exposure that was long enough to induce emphysema in a control group, Japanese researchers report in February issue of the American Journal of Physiology-Lung Cellular and Molecular Physiology.
Researchers at Juntendo University School of Medicine first compared the reaction of two mostly similar mouse strains to inhaled cigarette smoke. Since the lungs of one of the mouse strains “naturally” age very quickly, the researchers believed that exposure to inhaled cigarette smoke would induce emphysema in that strain much more quickly than in the other strain. And indeed, they found that after eight weeks of breathing 1.5% tobacco smoke through the nose for 30 minutes a day, five days a week, the test strain, called SAMP1, did develop emphysema, while the control strain, called SAMR1, did not.
50% tomato juice drink “completely prevented” smoke-induced emphysema
Then, using the same experimental method, but substituting a 50% tomato juice mixture for their regular water supply, the researchers again compared the effect of smoking on the mice. They found that “smoke-induced emphysema was completely prevented by concomitant ingestion of lycopene (a potent antioxidant) given as tomato juice” in SAMP1 mice. They added: “Smoke exposure increased apoptosis and active caspase-3 of airway and alveolar septal cells and reduced VEGF in lung tissues, but tomato juice ingestion significantly reduced apoptosis and increased tissue VEGF level.”
The paper, “Tomato juice prevents senescence-accelerated mouse P1 strain from developing emphysema induced by chronic exposure to tobacco smoke,” appears in the February issue of the American Journal of Physiology-Lung Cellular and Molecular Physiology, published by the American Physiological Society. Research was performed by Satoshi Kasagi, Kuniaki Seyama, Hiroaki Mori, Sanae Souma, Tadashi Sato, Taeko Akiyoshi and Yoshinosuke Fukuchi at the Juntendo University School of Medicine, Tokyo, and Hiroyuki Suganuma of the Kagome Research Institute, Tochigi, Japan.
FDA questions if effect is from lycopene alone or tomato juice; Japanese concur
The tomato-lycopene link is made even more interesting because late last year the U.S. Food and Drug Administration gave permission for some tomato products to carry highly-qualified labeling claims linking men’s eating tomato products with a reduced incidence of prostate cancer. In reaching its decision, the FDA noted that it’s unclear whether lycopene alone is responsible for the tomato products’ effect.
Similarly, the Japanese researchers noted: “Since mice were given tomato juice instead of pure lycopene preparation, we can not exclude the possibility that other ingredients contained in tomato juice affected the results….”
Model for further study of pathophysiology and therapeutic intervention
Kuniaki Seyama, coauthor and project leader for the study, said: “The study demonstrated that the SAMP1 strain is a useful model for cigarette-smoke induced emphysema and a valuable tool to explore both pathophysiologic mechanisms and the effect of therapeutic intervention on smoke-induced emphysema.”
Seyama, who is an assistant professor at Juntendo, said the researchers started out to find a good animal model for studying smoking, which is a major health problem in Japan as well as globally. “The basic concept was to establish a mouse model. We looked at the senescence-accelerated mouse (SAM) because it reaches old age after normal development and maturation, and we believe that aging itself is an important component in emphysema.”
Lycopene used because it’s a naturally-occurring oxidant in food