التحري عن بنية العظام ودور تمارين الجري في ذكور الجرذان المصابة بهشاشة العظام بواسطة مسار RANKL/RANK-OPG

Investigation Of Osteogenesis And The Role Of Treadmill Exercise In Osteoporotic Male Rats By RANKL/RANK-OPG Pathway

Summary
Osteoporosis is bone loss density and deterioration of bone tissues, osteoclasts are generally regarded as the only cells capable of resorbing to bone, physical exercise by Treadmill has positive preventive and therapeutic effects on osteoclast activity.
The experiment employed 24 male rats, randomly divided equally three groups 8)each group), the first group as control group, and the second group rats were given daily 200 mg/kg BW (D-gal) injected intraperitoneally for sixty days. The third group, animals were given daily 200mg/kg BW D-galactose with use of a treadmill at 25 m/min for 5 days weekly for sixty days. First day,30 and 60 days of the experiment was performed to evaluate the bone mineral density (BMD) at the femur of rats. Blood samples were drawn for biochemical analysis to by measuring bone restoration and formation biomarkers represented by Receptor Activator of Nuclear Factor Kappa-B (RANK), Receptor Activator of Nuclear Factor Kappa-B ligand (RANK-L), Cathapsin K, and osteoprotegrin (OPG), serum electrolyte (Ca, Na ,K,and P) , serum hormones(serum PTH, and calcitonin) , and serum Vit D. The femur bone following synthesis of cDNA, gene specific primers used to determine the level of gene Runx2. After preserving the femoral bone to examined by use light microscope and scanning electron microscope(SEM).
The results investigate a significant increase in serum RANK, RANK-L, and cathapsin-K levels in osteoporotic rats with D-gal, while OPG analysis revealed a significant decline in this groups. while the impact of the (treadmill+D-gal) showed a significant decrease in the levels of serum, RANK, RANKL, and Cathepsin K compared with the D-gal group. Asignificant increase of serum in the PTH, Vit D, calcitonin & Ca in the osteoporotic rats compare with other groups, while serum Na and K showed a significant decline in osteoporotic rats group as compare with other groups. While impact of (treadmill+D-gal)showed a significant
decrease in the level of the serum PTH, Vit D , calcitonin & Ca compare with control group.The D-gal case imbalance in the Ca related hormone (PTH & calcitonin ) which lead to imbalance in the Ca an the mineral in the body treadmill exercise stimulates bone formation and suppresses bone resorption. The gene expression (Runx 2) showed a significant increase in the D-gal group as compare with the other two group. The X-ray photography showed a significant decrease in the bone density in the D-gal group as compare with the (treadmill+D-gal) and the control group.
The femur rats histological examination of osteoporotic group showed resorption and marked thinning of trabecular with numerous osteoclasts while the (D-gal +treadmill) groups showed newly added lamellar structure and number of osteocytes with fewer cavities in the bony plates and reduction in micro-fissure in femur compact bone by using electron microscope, exercise increases cancellous bone mass through increased bone formation decreased bone absorption, and increased cortical bone mass due to increased periosteal bone formation. results of the bone examined under the light microscope showed a differences between the control group and the D-gal group, as the D-gal group has activated osteoclast cells, which cause bone necrosis and failure to perform their functions properly, which leads to weakness in the bone tissue while the (D-gal +treadmill) groups showed thicker trabecular and denser bone lamellae within the haversian canals (cavities within the bone) of the treadmill exercising rates.
In conclusion treadmill sport can emolliate the level of serum RANKL-RANK OPG pathway and decrease level of the serum Cathepsin K with up regulation of the Runx2 gene expression on the osteoporosis induced by D-galctose.