In this study, we investigated whether osteoporosis-like phenotype could be induced in the transgenic larvae when heat-shock was applied at earlier time points, namely when larvae were at 1,2,3,4,5, or 6 dpf. The obtained results show that heat-shocks from the time point of 3 dpf onwards resulted in osteoporosis-like phenotype, while heat-shock at 1 or 2 dpf did not affect mineralized bone matrix in 11 dpf larvae. | VNU Journal of Science Natural Sciences and Technology Vol. 37 No. 3 2021 37-43 Original Article Determination of the Earliest Time for Heat-shock Inducing Osteoporosis-like Phenotype in the rankl HSE CFP Medaka Fish Model for Osteoporosis To Thanh Thuy Phan Cong Son Tran Duc Long VNU University of Science 334 Nguyen Trai Thanh Xuan Hanoi Vietnam Received 10 August 2021 Revised 23 August 2021 Accepted 30 August 2021 Abstract The transgenic medaka rankl HSE CFP expressing Rankl a stimulator for osteoclastogenesis - the formation and activation of osteoclasts bone eating cells under the control of a heat inducible promotor has been established as a model for osteoporosis to evaluate antiosteoporosis effects of substances. Transgenic larvae are usually heat-shocked for 90 minutes at 39 oC when they are at 9 days post fertilization dpf and osteoporosis-like phenotype is analysed when larvae are at 11 dpf. In this study we investigated whether osteoporosis-like phenotype could be induced in the transgenic larvae when heat-shock was applied at earlier time points namely when larvae were at 1 2 3 4 5 or 6 dpf. The obtained results show that heat-shocks from the time point of 3 dpf onwards resulted in osteoporosis-like phenotype while heat-shock at 1 or 2 dpf did not affect mineralized bone matrix in 11 dpf larvae. These provide important evidence for study of onset of Rankl induced osteoclasts in fish and help improve experimental procedures using this fish model for osteoporosis. Keywords Medaka heat-shock osteoclasts rankl osteoporosis fish model. 1. Introduction people diagnosed with the disease and the number of affected people is increasing Osteoporosis is a common bone disorder dramatically due to aging population and lack characterized by decrease in bone density and of effective and safe drugs and therapies 2 . structure resulting in elevated risk of bone Animal models are always important for fracture. This disease is most prevalent in research to develop better
