دراسة تأثير مستقبلات الاستروجين ألفا وبيتا مع مسارات RANK وRANK-L وOPG في هشاشة العظام الناجمة عن استئصال المبيض في الأرانب الإناث

Investigation the effect of Estrogen Alpha and Beta receptors with RANK, RANK-L and OPG pathway in the Osteoporosis induced by Ovariectomy in female Rabbits.

Summary
Estrogen hormones play a crucial role in bone metabolism and the maintenance of bone mineral density. The aim of the current study was to Investigation the effect of Estrogen Alpha and Beta receptors with RANK, RANK-L and OPG pathway in the Osteoporosis induced by Ovariectomy in female Rabbits.
Twenty rabbits four-month-old female New Zealand White rabbits (weighing 3–3.25 kg) were randomly divided into two groups (10 each): a control group and an ovariectomized (OVX) group. Six weeks after the experiment, the rabbits underwent femoral radiography. Blood samples were drawn for chemical analysis, including serum hormone levels estrogen, progesterone, luteinizing hormone (LH), Follicle-stimulating hormone (FSH), serum salt levels Calcium (Ca), and bone biomarkers RANK, RANKL and Osteoprotegrin (OPG), Cathepsin k. Femoral samples were also taken for histological examination and gene expression testing of estrogen receptor alpha and beta.
The results showed a decrease in estrogen and progesterone levels in the OVX group compared to the control group and a clear increase in levels, luteinizing hormone (LH), Follicle-stimulating hormone (FSH), Calcium (Ca) level in rabbits with osteoporosis OVX compared to the control group, while the serum showed a clear increase in the levels RANK, RANKL, Cathepsin k in rabbits with osteoporosis, However, study showed that this group’s OVX significantly decreased as compared to the control group. The OVX group’s bone density significantly decreased, according to X-ray photography compared to the control group.
Examination of gene expression of estrogen receptor alpha and beta in bones showed downregulation of gene expression of estrogen receptor alpha and upregulation of estrogen receptor beta in the OVX group compared to the control group. Histological examination of the femur of rabbits in the OVX group showed resorption with thinning of the bone plates and the presence of many osteoclasts compared to the control group.
Conclusion: The current study found that osteoporosis and the degradation of bone-forming tissues and cells are directly impacted by a decrease in estrogen hormone. Downregulation of estrogen receptor alpha gene expression means the loss of the most important pathway that maintains the balance between bone formation and bone breakdown, leading to weak bone structure and an increased risk of osteoporosis after a bilateral ovariectomy or menopause. This loss is partially compensated for by estrogen receptor beta, but its replacement is insufficient to replace the specific functions of estrogen receptor alpha.