The effect of ascorbic acid on the plasma fibronectin concentration in human adults, guinea pigs and mice.

• Main Authors: Yi-Ping Yin, 尹依萍
• Other Authors: Cheng-Chin Hsu
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/15538442038335912668

碩士 === 中山醫學院 === 營養科學研究所 === 87 === Ascorbate is one of the important components effect on synthesis of collagen, and collagen was also a major extracellular matrix components. However, the effect of dietary ascorbate on the other components of extracellular matrix is still unclear. Fibronectin is an important components in the extracellular matrix family, which related to cell adhesion, differentiation, migration, and wound healing. The purpose of this study is to investigate the influence of dietary ascorbate on the plasma fibronectin concentration among the mice(that can synthesis ascorbate spontaneously), guinea pigs and human adults(that need supplement ascorbate from diet). Male ICR strain mice were separated into 3 groups (n=45), and fed diets containing ascorbate 0% (n=15), 1% (n=15), or 10% (n=15) for 2 months respectively. Male Hartley strain guinea pigs were separated into 4 groups (n=24), treated with the dietary ascorbate in following concentration (mg ascorbate/100 g diet), 0 mg (depleted; n=6), 50 mg (adequated; n=6), 250 mg (ampled; n=6), 3000 mg (tissue saturating; n=6) for 3 weeks respectively. Adults (average 21.3 years old; male=7, female=8) were supplemented by adding ascorbate 1000 mg/day into diets for 1 month. An enzyme-linked immunosorbent assay (ELISA) was used for measuring the quantity. The plasma ascorbate, fibronectin and hydroxyproline concentration rise significantly in the group of mice fed with 10% ascorbate. In guinea pigs, the concentration of plasma ascorbate is dose-dependent, however the concentration of fibronectin, is significant lower in saturating group (374±49 mg/ml) as compared with both depleted (548±167 mg/ml) and adequated (629±268 mg/ml) groups (P<0.05). This may suggest that high dose of ascorbate could inhibit the synthesis of fibronectin. In adults , the concentration of plasma ascorbate increased along with supplementing ascorbate, however it maintain at stable after reached the maximum level. The excretion of ascorbate in urine reached the maximum after one month ascorbate supplement, however, it decreased to the original concentration after stop supplement. This showed that human can regulate plasma ascorbate concentration, spontaneously. Furthermore, the change of plasma fibronectin concentration in human is similar to guinea pig, which indicated that treatment of ascorbate long term will decrease the concentration of plasma fibronectin. The possible mechanism for the effect of dietary ascorbate on plasma fibronectin needs further study and is currently under investigation.