Abstract
Zinc is a very important trace element, and it plays a manifest role in growth and development. In this study, the effects of zinc on the enchondral ossification at the metaphysis of the tibia in rats were observed.
Forty male Wistar rats, aged five weeks, were used. They were divided into four group as follows, the control group, the zinc deficient diet group, the low zinc diet (50%) group and the high zinc (150%) diet group. We obtained the results as follows.
1. Bone density
A significant difference was found between the zinc deficient diet group and the other groups, with the zinc deficient group showing a lower value. Between the low zinc diet group and the high zinc diet group, a significant difference was noted as well, with the high zinc diet group showing a higher value.
2. Histopathological findings
Compared with the control group, it was noted that in the zinc deficient diet group that there was an increase in the number of proliferate chondrocytes, irregular arrangement of the hypertrophic chrondrocytes, a decrease in the number of chondroclasts, a decrease in calcification, and a delayed ossification in the trabeculae and the thinner osteoid. Along with the increase in the volume of the intake of zinc, it was noted that there was a dense arrangement of chondrocytes and an increase in chondroclast. It was also found that there was active replacement from calfilage to bone and an increase in osteoblast and dense trabeculae. In the high zinc diet group those changes were very evident, which suggested more active enchondral ossification in this group than in the control group.
3. Hematological findings
Significant differences were noted in the serum level of calcium, the ratio of calcium to phosphorus and chloride between the control group and the high zinc diet group, between the zinc deficient diet group and the high zinc diet group, and between the low zinc diet group and the high zinc diet group. (p<0.01). In the high zinc diet group, CI showed significantly lower value among four groups. Significant differences were also found in the serum level of sodium between the zinc deficient diet group and the low zinc diet group, between the zinc deficient diet group and the high zinc diet group, and between the low zinc diet group and the high zinc diet group. The level of LDH in the low zinc diet group was lower than in the control group, while ALP noted a significant difference between the control group and the zinc deficient group, and between the zinc deficient group and the low zinc diet group (p<0.01).
Based on the foregoing results, it has been shown that the zinc deficit would result in an inhibition of enchondral ossification in the tibia of rats and the increase in the volume of the intake of zinc had a beneficial effect on bone formation.
