TGFB1 and asthma: RT‐qPCR and western blot analysis showed that the expression levels of TGF‐β1 and Smad2 in lung tissues of mice in the model group were elevated (Figure 5A,B, p < .01, vs. sham group), indicating that asthma can activate the TGF‐β1/Smad2 signaling pathway.