HMOX1 and acute kidney injury: In addition, in order to further identify the role of the Nrf2/HO-1 signaling pathway in the process of paricalcitol protecting the kidneys, we use ZnPP to inhibit Nrf2/HO-1 signaling according to previous reports [44] and found that, unsurprisingly, the positive effect of paricalcitol on the renal tissues of AKI mice was attenuated.