3.3 LCZ696 treatment and TLR2 knockdown attenuated doxorubicin-induced cardiac inflammation in mice.
As previously reported, fibrosis and inflammation complement each other during disease. Moreover, considering the potential effect of LCZ696 and the critical role of TLR2 in anti-inflammatory processes, we next assessed the inflammatory response in the hearts of each group.
Immunohistochemistry staining showed that DOX promoted a significant increase in TNF-α in the hearts of the model mice compared to that in the hearts of control mice. As expected, LCZ696 treatment and TLR2 knockdown prevented the heart from developing high TNF-α expression (Figure 3A and Supplementary Figure 2A). Similar results were also observed in the ELISA results (Figure 3B). NF-κB-related proteins, as well-established downstream signaling proteins in the TLR2 pathway, participate in acute and chronic inflammation. Then, we tested whether these alterations occurred in heart tissues. As shown in Figure 3C-D, LCZ696 treatment and TLR2 deficiency effectively prevented IκBα degradation (Figure 3C) and inhibited the nuclear translation of NF-κB (Figure 3D) in heart tissue compared with that in DOX-induced mice. Moreover, the mRNA levels of the pro-inflammation-related genesTnfα (Figure 3E), Mcp1 (Figure 3F) and Il6 (Figure 3G) were validated by RT-qPCR, which provided additional evidence to show the anti-inflammatory effects of LCZ696 treatment and TLR2 deficiency.
Thus, these results indicated that LCZ696 treatment and TLR2 deficiency significantly inhibited DOX-induced cardiac inflammation in heart tissues, which may be associated with the cardioprotective effect.