Abstract

Dietary silicon and arginine affect mineral element composition of rat femur and vertebra.

Both arginine and silicon affect collagen formation and bone mineralization. Thus, an experiment was designed to determine if dietary arginine would alter the effect of dietary silicon on bone mineralization and vice versa. Male weanling Sprague-Dawley rats were assigned to groups of 12 in a 2 x 2 factorially arranged experiment. Supplemented to a ground corn/casein basal diet containing 2.3 microg Si/g and adequate arginine were silicon as sodium metasilicate at 0 or 35 microg/g diet and arginine at 0 or 5 mg/g diet. The rats were fed ad libitum deionized water and their respective diets for 8 wk. Body weight, liver weight/body weight ratio, and plasma silicon were decreased, and plasma alkaline phosphatase activity was increased by silicon deprivation. Silicon deprivation also decreased femoral calcium, copper, potassium, and zinc concentrations, but increased the femoral manganese concentration. Arginine supplementation decreased femoral molybdenum concentration but increased the femoral manganese concentration. Vertebral concentrations of phosphorus, sodium, potassium, copper, manganese, and zinc were decreased by silicon deprivation. Arginine supplementation increased vertebral concentrations of sodium, potassium, manganese, zinc, and iron. The arginine effects were more marked in the silicon-deprived animals, especially in the vertebra. Germanium concentrations of the femur and vertebra were affected by an interaction between silicon and arginine; the concentrations were decreased by silicon deprivation in those animals not fed supplemental arginine. The change in germanium is consistent with a previous finding by us suggesting that this element may be physiologically important, especially as related to bone DNA concentrations. The femoral and vertebral mineral findings support the contention that silicon has a physiological role in bone formation and that arginine intake can affect that role.

Seaborn CD, Nielsen FH
Biol Trace Elem Res Dec 2002
PMID: 12462747

Arginine is an essential amino acid for the rat. In animals L-arginine apparently induces growth hormone and insulin-like growth factor-1 responses and stimulates nitric oxide synthase. Growth hormone and insulin-like growth factor-1 are important mediators of bone turnover and osteoblastic bone formation, whereas nitric oxide is a potent inhibitor of osteoclastic bone resorption (1). By affecting these physiological regulators of bone remodeling, L-arginine could potentially increase bone formation over bone resorption and, consequently, increase bone mass.

There is experimental evidence suggesting that arginine supplementation promotes bone formation. A mixture of lactose, L-arginine, and L-lysine improved fracture healing of rabbits subjected to an osteotomy of the left fibula (2). These authors suggested that arginine was involved not only in the increase of intestinal calcium absorption but also in collagen synthesis. Although there is evidence that L-arginine affects bone maintenance minimal attention has been given to the possible interaction between arginine and other macro and/or trace minerals, including silicon associated with mineralized bone formation and remodeling.

Silicon can affect bone formation and remodeling (3). The basic amino acids such as arginine can increase silicon absorption (4). Therefore the effects of silicon on bone mineralization may be modified by the amount of arginine in the diet….