Effects of ferric ammonium citrate on iron accumulation, bone turnover and bone density in ovariectomized rat models with osteoporosis.

To analyze the effect of ferric ammonium citrate on iron accumulation, bone turnover and bone density in ovariectomized rat models with osteoporosis, 40 female SD rats were randomized into four groups, that were, sham-operated, model, low and high-dose ferric ammonium citrate groups (i.e. low and high-dose groups) respectively, each of them had ten rats. Except for the sham-operated group, bilateral ovariectomy was performed in the other groups to establish models with osteoporosis; one week after the operation, those in the low and high-dose groups were given 90 mg/kg and 180 mg/kg ferric ammonium citrate, respectively. Those in the other two groups received isodose saline for nine weeks, with the frequency of twice per week. The changes in bone tissue morphology, serum ferritin concentration, tibial iron content, serum osteocalcin, carboxyl terminal peptide (β - CTX), bone density, bone volume fraction and trabecular thickness were compared. Results showed that the rats in the low and high-dose groups contained a higher concentration of serum ferritin and tibial iron content compared to the other groups (P < 0.05). In contrast to the model group, the bone trabeculae in the low and high-dose groups were sparse in morphology and increased in spacing. It was obvious that the rats contained more osteocalcin and β - CTX in the model group, the low and high-dose groups versus the sham-operated group (P < 0.05), and those had more β - CTX in the high-dose group versus the model group and the low-dose group (P < 0.05). The bone density, bone volume fraction and trabecular thickness of the rats in the model group, the low and high-dose groups showed lower versus the sham-operated group (P < 0.05); those in the low and high-dose groups significantly presented lower bone density and bone volume fraction versus the model group (P < 0.05). Iron accumulation can aggravate osteoporosis in ovariectomized rats, and its mechanism may be associated with accelerating bone turnover, promoting bone absorption, reducing bone density and sparsely trabecular structure. Therefore, it is particularly important to understand iron accumulation in postmenopausal osteoporosis patients.