Collagen metabolism in mouse lung after X irradiation.
Collagen and total protein synthesis rates have been determined in the lungs of CBA mice irradiated with single doses of X rays between 8 and 16 Gy. Mice were injected with [3H]proline accompanied by a large dose of unlabeled proline, and synthesis rates were measured at 2-month intervals from 8 to 31 weeks after irradiation. At 2 months after radiation treatment, collagen and total protein synthesis rates were significantly depressed but they had recovered by 4 months. By 6 months collagen synthesis rates had increased above control in a dose-dependent manner, so that in the 14-Gy dose group the fractional synthesis rate for collagen was 4.6 times higher than in control mice as measured by incorporation of [3H]proline. However, a significant net accumulation of collagen was seen only in the lungs of the highest dose group at 31 weeks, as indicated by total hydroxyproline measurements. There was a slight increase in the ratio of types I and III collagen. Late radiation damage in the CBA mouse lung is characterized by increased collagen metabolism, which may or may not lead to a net accumulation of collagen.
Murray
J C
JC
Gray Laboratory of the Cancer Research Campaign, Mount Vernon Hospital, Northwood, United Kingdom.
Parkins
C S
CS
D000818:Animals; D003094:Collagen / Q000378:metabolism*; D005355:Fibrosis / Q000378:metabolism; D006909:Hydroxyproline / Q000378:metabolism; D008168:Lung / Q000378:metabolism / Q000528:radiation effects*; D051379:Mice; D014176:Protein Biosynthesis; D011833:Radiation Injuries, Experimental / Q000378:metabolism*; D014965:X-Rays
D003094:Collagen; D006909:Hydroxyproline