An imbalance of proteinases and antiproteinases and especially Mmp and Timp (Figures 3(a) and 3(b)) is an important feature of the pathogenesis of chronic lung diseases [25, 26], and their expression is regulated by various inflammatory markers such as Tnf, IL-6, Cxcl1 [27, 28], and Cxcl2. Therefore, the findings of the present study, i.e., increased Mmp9 along with unaltered Timp1 transcript expression in the acrolein-exposed BALB/cByJ strain, indicate susceptibility to acrolein (Figures 3(a) and 3(b)). The gene discussed is MMP9; the disease is chronic lung disease.