背景和目的：myostatin 是transforming growth factor超級家族中之一員，並且對骨骼肌有負向的調控。我們假設myostatin 在慢性肺發炎時會表現，並且導致不只是呼吸肌肉還有全身性的肌肉耗損。方法：三隻老鼠由氣管給予1.5 U 的bleomycin sulfate ，另外兩隻老鼠作為控制組則是由氣管給予生理食鹽水。這些老鼠的橫隔膜、腓腸肌、胸大肌都取下，藉由逆轉錄鏈聚合反應測得myostatin 、myoD、myf5、myogenin 的mRNA 。結果：在慢性肺發炎組的老鼠，橫隔膜、腓腸肌、胸大肌的myostatin mRNA 都是上升；在控制組的老鼠，myostatin 表現沒有增加。結論：慢性肺發炎時，不只是局部而且全身肌肉都會表現較高的 myostatin。

Background and Purpose: Myostatin belongs to the transforming growth factor-superfamily and is known to be involved in the negative regulation of skeletal muscle mass. We hypothesized that myostatin is expressed in chronic lung inflammation, which results in muscle wasting in both respiratory and systemic muscles. Methods: Three rats received 1.5 U of bleomycin sulfate intratracheally. Control rats (n = 2) received saline. The messenger (m)RNA levels of myostatin, myoD, myf5, and myogenin of the diaphragm, gastrocnemius and pectoris major were studied with a reverse-transcription polymerase chain reaction. Results: mRNA levels of myostatin were elevated in the diaphragm, gastrocnemius, and pectoris major in the chronic lung inflammation group. The control group showed no increased myostatin expression. Conclusions: These data suggest that chronic lung inflammation can lead to higher myostatin expressions in both local and systemic muscles.