Effect of Ovariectomy with and without Replacement Therapy on Calcium Metabolism in Female Albino Rats | ||
| Bulletin of Egyptian Society for Physiological Sciences | ||
| Article 20, Volume 28, Issue 1, June 2008, Pages 287-306 PDF (295.28 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/besps.2008.36986 | ||
| Authors | ||
| Saad Taha* 1; Salah El Din El-Sayed2; Merhan Ragy2 | ||
| 1Physiology Dept., Faculty of Medicine, El-Azhar University | ||
| 2Physiology Dept., Faculty of Medicine, El-Minia University | ||
| Abstract | ||
| Osteoporosis is a chronic, progressive disease of the skeleton characterized by decreased bone mass due to a reduction in both organic and non organic components. Women are more likely todevelop the disease, especially postmenopausal women. The aim of the present workwas to assess the effect of ovariectomy with or without replacement therapy on calcium metabolism in female albino rats and the possibility of preventing progression of osteoporosis by means of hormonal supplementation and to compare the effects of different supplementations. The present study was done on 90 adult female albino rats that were divided four weeks after bilateral ovariectomy (OVX) (except the control group) into nine equal groups as follow: Control group (non-ovariectomized), Ovariectomized group, Ovariectomized estrogen treated (30 μg/kg/day SC, 8 weeks) group, Ovariectomized progesterone treated (10 mg/kg/day SC, 8 weeks) group, Ovariectomized estrogen (25 μg/kg/day SC, 8 weeks) and progesterone (10mg/kg/day S.C., 8 weeks) treated group, Ovariectomized calcium treated (70 µL/day – calcium gluconate 0.24gm/ml- orally, 8 weeks) group, Ovariectomized calcitonin treated (10 IU/kg SC, 8 weeks) group, Ovariectomized calcitonin and calcium treated group, Ovariectomized vitamin D treated (0.5µg/kg orally, 8 weeks) group. Blood samples were collected, centrifuged and used for determination of calcium, phosphorous, parathormone and calcitonin serum levels. The left femur of each rat was removed, cleaned, weighted in air and in water and the bone density was determined. Fat-free dry femurs obtained by extracting the femurs for 48 h in 90% petroleum ether and dried in a forced-air oven at 90 0 C until constant weight was obtained. The bone ash weight which contains the minerals was obtained after ashing at 600 0 C for 24 h. On the basis of the obtained weights the percentage of organic and non-organic components were calculated. The results obtained revealed that ovariectomy produced a significant reduction in bone mineral density (BMD), dry weight, ash content, femoral calcium content and organic matrix weight compared to the control group, indicating that there was a decrease in bone mass rather than a decrease in bone minerals. Serum calcium concentration did not show any significant change following OVX, serum calcitonin level decreased after OVX and increased with estrogen supplementation. The combination groups which were supplemented either with (estrogen and progesterone) or with (calcitonin and calcium)-with insignificant differences between them- increased BMD, dry weight, ash content, organic matrix weight and ash calcium content. The percentage changes in BMD were 18% and 17.3% in these groups respectively as compared to the ovariectomized group. Calcitonin decreased serum calcium level, increased partially BMD and increased significantly bone dry weight, organic matrix weight, ash content and ash calcium of left femur, compared to OVX group. The calcium supplemented ovariectomized group had insignificant difference with the ovariectomized group in all femur parameters. When it wss compared with the control group, there was a significant reduction in BMD. This finding could be explained that, calcium deposition in bone could be dependent on calcitonin level which was decreased by ovariectomy. So, calcium potentiates the effect of calcitonin on bone mass that ovariectomized calcitonin and calcium treated female group had better effect on bone mass than calcitonin therapy alone. The bone mass was greater by 16.31 % in vitamin D treated ovariectomized group, 15.96% in both estrogen and calcitonin treated ovariectomized groups and 15.6% in progesterone treated ovariectomized group when compared to OVX group. There was a significant higher serum phosphorus concentration in ovariectomized group compared to the control group, while other ovariectomized treated groups had serum phosphorus concentrations that were similar to those of the control group. There was an insignificant change in serum parathormone levels in the ovariectomized and the ovariectomized treated groups compared with the control group. In conclusion,the present study showed that the combination therapy either with estrogen and progesterone or with calcitonin and calcium was found to be the most effective treatment regimen in OVX rats. | ||
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