Comparison of vitamin C deficiency with food restriction on collagen cross-link ratios in bone, urine and skin of weanling guinea-pigs.

Abstract

Mild-to-moderate vitamin C depletion in weanling guinea-pigs affects pyridinoline:deoxypyridinoline (collagen cross-link) ratios in femur shaft and urine, attributed to impairment of hydroxylation of collagen lysine. We investigated: (1). whether the picture at two time points is compatible with progressive accumulation of abnormal collagen; (2). whether any changes are seen in skin, where little deoxypyridinoline occurs; (3). whether total food restriction has similar effects. Male weanling Dunkin-Hartley guinea-pigs were fed diets containing either 0.5 (vitamin C-restricted) or 160.0-320.0 (vitamin C-adequate) mg vitamin C/d. Two groups receiving the vitamin C-adequate diet received it ad libitum. Two other groups received the vitamin C-adequate diet in a restricted amount, limited to that which permitted nearly the same growth rate as in the vitamin C-restricted groups. Animals were fed for 4 or 8 weeks; urine was collected, and vitamin C and collagen indices were measured. In the femur shaft, the hydroxyproline content per unit weight was unaffected by vitamin C restriction or by total food restriction. Deoxypyridinoline was increased and the pyridinoline:deoxypyridinoline ratio was decreased in vitamin C-restricted groups, but not in food-restricted groups. Changes in the value of the ratio were greater after 8 than after 4 weeks. Urine indices mirrored bone indices. In skin, the main effect of vitamin C restriction was to reduce hydroxyproline. Here, the cross-link ratios changed less markedly than in bone, and there was less deoxypyridinoline. We conclude that the picture at two time points is compatible with a progressive accumulation of pyridinoline-enriched collagen in vitamin C-deprived animals, that the picture in skin differs from that of bone and urine, and that cross-link changes are not produced by total food restriction.

• Authors: C J Bates, Harumi Tsuchiya
• Journal: The British journal of nutrition (Br J Nutr) Vol. 89 Issue 3 Pg. 303-10 (Mar 2003) ISSN: 0007-1145 [Print] England
• PMID: 12628025 (Publication Type: Journal Article)

Chemical References

• Amino Acids
• pyridinoline
• deoxypyridinoline
• Collagen
• Ascorbic Acid

Topics

• Amino Acids (metabolism, urine)
• Animals
• Ascorbic Acid (metabolism)
• Ascorbic Acid Deficiency (metabolism, urine)
• Body Weight
• Bone and Bones (metabolism)
• Collagen (metabolism)
• Eating
• Food Deprivation
• Guinea Pigs
• Male
• Skin (metabolism)