CCND1 and Bloom syndrome: The results of RT-qPCR showed that compared with the BLM group, the mRNA expression levels of cyclin D1, FN1 and collagen III in BLM + WYHZTL-M, BLM + WYHZTL-H and BLM + XAV-939 group were downregulated (P < 0.05, P < 0.01, P < 0.01; all P < 0.01; all P < 0.01, respectively), while BLM + WYHZTL-L group didn’t significantly change (P > 0.05) (Fig. 2f, j and l).