全面性雄性素受體剔除小鼠（ARKO mice）在生長期間跟野生型小鼠
（Wild type mice）相比，其骨質密度（BMD）雖然減少了，但我們卻發現
其骨頭的型態塑造（bone modeling）亦不正常。因為人類骨質疏鬆症
（osteoporosis）病患的骨頭塑造是正常，而造成骨質疏鬆症的原因是骨頭
的再塑期（bone remodeling）出了問題。因此這種全面性雄性素受體剔除之
小鼠已不再適合做為骨質疏鬆症的動物模型。為了更完美的動物模型，我
們製作一隻誘導性雄性素受體剔除鼠，策略是將購自Jackson Lab 誘導性的
抗粘病毒基因 1-可力鼠（Mx1-cre）與我們的雄性素受體洛克斯鼠（flox-AR
mice）交配產生抗粘病毒基因 1-雄性素受體剔除（Mx1-ARKO）。除非注
射干擾素甲（interferon- ），否則這隻老鼠的雄性素受體將保持正常。我們
在這隻小鼠骨頭塑造完成長大成鼠後再注射干擾素甲誘發雄性素受體剔
除，以此來避免過早剔除使骨頭塑造異常而影響骨頭再塑的研究。結果顯
示，分析Mx1-ARKO 小鼠各器官之雄性素受體基因的量，其肝臟、骨頭、
腦的雄性素受體基因的量跟野生型小鼠相比都有減少（P < 0.05）。微斷層掃
瞄（Micro CT）分析股骨、脊椎骨之骨小梁的各參數，其骨頭的質量確實
也有減少（P < 0.05），皮質骨（Cortical bone）的厚度（Thickness）和週長
（Perimeter）也都有差異（P < 0.05）。由於Mx1-ARKO 小鼠骨頭的質量都
減少了，所以對外力的耐受性也會比較差，骨頭變得比較脆弱、易斷。實
驗結果證實，在小鼠成熟時將雄性素受體剔除可以讓小鼠骨頭發展正常，
而後又會造成小鼠產生骨質疏鬆的現象。本動物模型將是研究雄性素受體
對骨密度影響的有力工具。累積的知識將對骨質疏鬆症的治療與新藥的發
展有莫大的幫助。全面性雄性素受體剔除小鼠（ARKO mice）在生長期間跟?.. During the mouse bone growth, the bone mineral density（BMD）of general
androgen receptor knockout（ARKO）mice is lower than that of WT（wild type）
mice. However, we found that the bone modeling in adult ARKO mice is
abnormal. In human beings, the bone modeling in osteoporosis patients is
normal, but the bone remodeling in osteoporosis patients is defective. Therefore,
these general ARKO mice are not a suitable animal model for studying
osteoporosis. In order to mimic the human osteoporosis model, we proposed to
induce ARKO in adult mice. Our strategy was to cross-match our flox-AR mice
with the inducible MX1-cre mice. AR would only be knocked out in
MX1-ARKO mice after interferon-alpha injection. We then compared the
difference in bone metabolism between ARKO and intact AR mice to investigate
the role of AR in bone remodeling. We found that the AR RNA level in liver,
bone, brain and testis in Mx1 ARKO mice was less than that in WT mice（P <
0.05）. The analysis of bone parameters in trabecular bone of femur and vertebral
bone by Micro-CT revealed that the bone mass indeed decreased（P < 0.05）.
There also were differences in thickness and perimeter in cortical bone. Because
of the decreased bone mass in Mx1-ARKO mice, the tolerance to external force
was worse and bones are more fragile and easy-broken compared to WT mice.
In conclusion, we created a knockout AR model in adult mice after normal
bone development. And the results showed the inducible ARKO mice became
osteoporotic after losing AR. The MX1-ARKO model in our study was proven
to be a powerful tool to study the role of androgen receptor in bone homeostasis.
The collecting knowledge will greatly influence the treatment and the new drug
development for osteoporosis in the future by modulating the AR activity.
