POLR3H and pulmonary fibrosis: According to the results of qRT-PCR, the expression levels of ENPP3, PDE7B, and ENTPD1 were elevated, while the expression levels of PNMT, GPX3, and POLR3H were decreased in the lung tissues of bleomycin-induced pulmonary fibrosis mice compared with the sham group (Figure 8).