ビタミンとミネラル

Zinc Improves the Bone Mechanical Strength in Ovariectomized Rat Model by Restoring Bone Composition and Hydroxyapatite Crystallite Dimension

Abstract

Payal Bhardwaj, DurgVijay Rai and Mohan Lal Garg

Purpose: Osteoporosis is a bone metabolic disorder which is well known to increase bone porosity and is the outcome of various factors like ageing, genetic, nutritional deficiency, decreased calcium uptake, and last but the most important hormonal imbalances. Hormonal imbalance is one of the major factors affecting women worldwide and leading to osteoporosis. Trace elements play a very essential role in number of pathological conditions. Ingestion of zinc in the early stages of bone loss may be more beneficial in mitigating bone loss and also in improving the overall strength of the bone. In the current work, we have intended to extract the information pertaining to the mechanical strength of bone, bone tissue composition and hydroxyapatite crystallite size upon supplementing zinc in the osteopenic condition. Methods: Forty eight wistar female rats in two set of twenty four animals each were assigned to four groups: Control, Zinc, Ovariectomized (OVX) and OVX+Zinc. Duration of the treatment period was of eight weeks. Biochemical estimations were carried out to make comparison between the treatment groups based on bone metabolism markers in serum. Bone mechanical strength of both the bones i.e., femur and tibia, was assessed using texture analyzer. Also, bone matrix analysis using Fourier transformer infrared spectroscopy and X-ray diffraction studies were carried out for all the treatment groups. Results: Estradiol levels decreased and tartarate-resistant acid phosphatase 5b levels increased in the OVX group. Zinc supplemented following ovariectomy regulated these levels. The OVX group showed significantly higher serum alkaline phosphatase levels, which recovered upon zinc supplementation. Further, zinc plays a potential role in preventing bone tissue deterioration by restoring its composition and microstructure in the post-menopausal condition, thereby, maintaining the mechanical strength of the bone. Conclusion: These findings suggested that alterations in the bone tissue material properties following estrogen deficiency can be averted by zinc if administered at early stages of bone loss.