Relationship between pulmonary surfactant protein and lipid peroxidation in lung injury due to paraquat intoxication in rats.
BACKGROUND
Pulmonary damage resulting from lipid peroxidation is a principal effect of paraquat intoxication. The host-defense functions of surfactant are known to be mediated by the surfactant proteins A and D (SP-A and SP-D, respectively). The primary objective of this study was to evaluate the variations over time in levels of surfactant protein and lipid peroxidation (LPO) in lung tissue following free-radical-induced injury.


METHODS
42 adult, male, Sprague-Dawley rats were administered intraperitoneal injections of paraquat (35 mg/kg body weight). SP-A and SP-D levels were determined via Western blot. LPO in the left lung homogenate was measured via analyses of the levels of thiobarbituric acid-reactive substances.


RESULTS
LPO levels peaked at 6 hours, with no associated histological changes. SP-D levels increased until hour 12 and declined until hour 48; SP-D levels subsequently began to increase again, peaking at hour 72. SP-A levels peaked at hour 6, declining thereafter.


CONCLUSIONS
We suggest that in the early phase of paraquat injury, SP-D levels reflect alveolar damage and that de novo synthesis of SP-D takes 72 hours. Levels of SP-A, on the other hand, reflect abnormalities in the surfactant system in the late stage of paraquat intoxication. Surfactant proteins may play a role in protecting the lungs from reactive oxygen injury. A time-dependent variation has been observed in the levels of surfactant proteins A and D following paraquat injury, and it has been suggested that these proteins play a role in the protection of lung tissue against ROS-induced injuries.
Gil
Hyo-Wook
HW
Department of Internal Medicine, Soonchunhyang University Medical College, Cheonan Hospital, Cheonan, Korea.
Oh
Mi-Hae
MH
Woo
Kee-Min
KM
Lee
Eun-Young
EY
Oh
Myung-Ho
MH
Hong
Sae-Yong
SY
D000818:Animals; D005609:Free Radicals / Q000633:toxicity*; D006540:Herbicides / Q000633:toxicity*; D015227:Lipid Peroxidation; D008168:Lung / Q000187:drug effects*; D008297:Male; D010269:Paraquat / Q000633:toxicity*; D037661:Pulmonary Surfactant-Associated Proteins / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000633:toxicity; D012128:Respiratory Distress Syndrome / Q000139:chemically induced*
D005609:Free Radicals; D006540:Herbicides; D037661:Pulmonary Surfactant-Associated Proteins; D017382:Reactive Oxygen Species; D010269:Paraquat