CHANGES IN THE FATTY ACID COMPOSITION AND　HYDROXYPROLINE CONTENT IN RAT LUNG IN RELATION TO COLLAGEN SYNTHESIS AFTER PARAQUAT ADMINISTRATION

［Original Article］

CHANGES IN THE FATTY ACID COMPOSITION AND HYDROXYPROLINE
CONTENT IN RAT LUNG IN RELATION TO COLLAGEN SYNTHESIS
AFTER PARAQUAT ADMINISTRATION

TETSUHITO FUKUSHIMA¹, KEIKO TANAKA², HEEJIN LIM³
and MASAKI MORIYAMA²

¹⁾Department of Hygiene & Preventive Medicine, Fukushima Medical University
School of Medicine, Fukushima
²⁾Department of Public Health, School of Medicine, Fukuoka University, Fukuoka
³⁾Department of Health Education, Ewha Womans University, Seoul, Korea

(Received March 17, 2003, accepted May 6, 2003)

Abstract: Objectives: Effect of paraquat on the fatty acid composition (weight percentage) of rat lung was studied with particular reference to the change of hydroxyproline content in the course of paraquat-induced dysfunction and subsequent repair.
　　Methods: Eight-week-old male Wistar rats were administered paraquat at 20 mg/kg body weight subcutaneously, and the wet weight, hydroxyproline content and fatty acid composition of lungs of each group rats were analyzed at 2, 7, 14 or 28 days after treatment, respectively.
　　Results: The percentage of palmitic acid (C16 : 0), arachidonic acid (C20: 4) and docosahexaenoic acid (C22 : 6) significantly increased, and the percentage of oleic acid (C18 : 1) and the ratio of monounsaturated fatty acids/saturated fatty acids (M/S) significantly decreased comparing to control on day 28 after paraquat administration.　The time-course of each fatty acid was observed for 28 days after paraquat administration.　M/S ratio decreased after paraquat administration up to the 28^th day, but the polyunsaturated fatty acids/saturated fatty acids (P/S) ratio decreased during the first 7 days, followed by a increase, and then reached higher level than the 0 day control at the 28^th day.　Hydroxyproline also increased between the 14^th and the 28^th days.　Eicosapentaenoic acid (C20 : 5) had once increased during the first 2 days and decreased gradually, while C20 : 4 maintained high level in this period.　C22 : 6 increased after paraquat administration and maintained high level up to the 28^th day.　This result indicated that desaturation and elongation in n-3 series fatty acids were accelerated after paraquat treatment, and consequently C20 : 5 was rapidly converted into C22 : 6 and decreased.
　Conclusions: Paraquat might cause elevation of unsaturated fatty acids, especially C20 : 4 but not C20 : 5 by the stimulation of the fatty acid desaturase system, and could consequently stimulate local collagen synthesis by C20 : 4 metabolites in the healing stage.

Key words: paraquat, lipid peroxidation, fatty acid composition, hydroxyproline, pulmonary fibrosis

福島哲仁，田中景子，林　姫辰，守山正樹

Correspondence to: Tetsuhito Fukushima, Department of Hygiene & Preventive Medicine, Fukushima Medical University School of Medicine, Fukushima City 960-1295, Japan.