Effects of Nd:YAG laser irradiation on morphometry and lung function in elastase-induced emphysema in rats.
OBJECTIVE
Although thoracoscopic laser ablation therapy has been hailed as an effective surgical treatment for diffuse emphysema, no one has as yet made an in-depth study of the efficacy of this treatment. This investigation was undertaken to research the effects of laser pneumoplasty on an animal model of emphysema.


METHODS
Eight weeks after elastase treatment, the rats' left lungs were irradiated using contact Nd:YAG laser. Pulmonary function tests were performed 4 weeks after irradiation and the lungs were prepared for histologic examination.


RESULTS
Dense fibrous scars beneath the pleura were observed at 4 weeks after irradiation. Although mean linear intercept values of irradiated lungs were not much lower than those in the non-irradiated elastase-treated group, laser irradiation caused a significant decrease in lung volume. While there was no significant difference in quasistatic compliance, elastic recoil pressure of the lung increased to control levels at total lung capacity volume.


CONCLUSIONS
We conclude that laser therapy does not cause normalization of compliance, or improvement in the deeper part of the emphysematous lung, but rather a peripheral volume reduction and "encasement effect" on the lungs as a result of fibrotic scars.
Akahane
T
T
Second Department of Surgery, Tohoku University School of Medicine, Sendai, Japan.
Kurokawa
Y
Y
Chiba
R
R
Yaegashi
H
H
Takahashi
T
T
Satomi
S
S
D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D053685:Laser Therapy / Q000379:methods / Q000706:statistics & numerical data; D008168:Lung / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D010196:Pancreatic Elastase; D011656:Pulmonary Emphysema / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D051381:Rats; D017208:Rats, Wistar; D012129:Respiratory Function Tests / Q000706:statistics & numerical data; D013908:Thoracotomy
D010196:Pancreatic Elastase