Vitamin C intake inhibits serum lipid peroxidation and osteoclast differentiation on alveolar bone in rats fed on a high-cholesterol diet.
OBJECTIVE
A high-cholesterol diet stimulates osteoclast differentiation, which may be induced by increased serum lipid peroxidation. The inhibition of serum lipid peroxidation by vitamin C may offer beneficial effects on osteoclast differentiation including increased expression of receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) and NF-kappaB. This study investigated the effects of vitamin C intake on RANKL and NF-kappaB expression in periodontal tissue of rats fed a high-cholesterol diet.


METHODS
Twenty-four rats (8 weeks old) were divided into four groups: a control group (fed a regular diet) and three experimental groups (fed a high-cholesterol diet supplemented with 0, 1 and 2 g/l vitamin C/day) in this 12-week study. Vitamin C was provided by its addition to drinking water. As an index of serum lipid peroxidation, hexanoyl-lysine (HEL) level was determined by a competitive enzyme-linked immunosorbent assay method. Immunohistological analysis was performed to evaluate RANKL and NF-kappaB expression on the alveolar bone surface. The number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts was also counted.


RESULTS
Feeding a high-cholesterol diet increased not only the serum HEL level but also the number of TRAP-positive osteoclasts on the alveolar bone surface, with an increase in RANKL and NF-kappaB expression on alveolar bone surface. Intake of vitamin C reduced the serum HEL level and osteoclast differentiation, with decreasing RANKL and NF-kappaB expression.


CONCLUSIONS
Vitamin C intake could suppress osteoclast differentiation, including RANKL and NF-kappaB expression on the alveolar bone surface, by decreasing serum lipid peroxidation in rats fed a high-cholesterol diet.
Sanbe
Toshihiro
T
Department of Preventive Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama 700-8525, Japan.
Tomofuji
Takaaki
T
Ekuni
Daisuke
D
Azuma
Tetsuji
T
Irie
Koichiro
K
Tamaki
Naofumi
N
Yamamoto
Tatsuo
T
Morita
Manabu
M
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D002791:Cholesterol, Dietary / Q000008:administration & dosage; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D016328:NF-kappa B / Q000097:blood*; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D053245:RANK Ligand / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar
D000975:Antioxidants; D002791:Cholesterol, Dietary; D016328:NF-kappa B; D053245:RANK Ligand; D001205:Ascorbic Acid