Sika deer antler protein against acetaminophen-induced oxidative stress and apoptosis in HK-2 cells via activating Nrf2/keap1/HO-1 pathway.

Nf-E2-related transcription factor 2 (Nrf2) helps cells fight oxidative stress events in vivo and in vitro by promoting the expression of antioxidants and detoxification enzymes. The necessary factors regulating Nrf2 activity and stability during analgesic nephropathy are not fully understood. Our results suggest that acetaminophen produces nephrotoxicity in HK-2 cells by inhibiting keap1 degradation. APAP subsided Nrf2 nuclear accumulation by inhibition of keap1 degradation, thereby reducing the binding of Nrf2 to ARE, leading to the loss of expression of antioxidant proteins such as HO-1, inducing a series of oxidative stress and apoptosis events. Therefore, Nrf2/keap1/HO-1 signal transduction pathway has a poor prognosis during analgesic nephrotoxicity. Sika deer antler protein (SDAPR) significantly prevented APAP-induced HK-2 cell damage by constitutively stabilized Nrf2 nuclear retention. Excess APAP leads to a decrease in Nrf2 nuclear translocation, leading to severe oxidative stress, increasing the levels of GSH and MDA in HK-2 cells, and reducing the enzyme activities of SOD and CAT in HK-2 cells. Increased biomarker levels of acute kidney injury (AKI) in HK-2 cells, including kidney injury molecule-1, neutrophil gelatinase-associated lipocalin and cystatin C, decrease the mitochondrial membrane potential in HK-2 cells, and cause mitochondrial dysfunction, it also reduced the ratio of mitochondria-associated apoptotic protein Bax/Bcl-2, leading to cell apoptosis. SDAPR dose dependently accorded protection against acetaminophen-induced nephrotoxicity, oxidative damage, and cell apoptosis by its molecular intervention with Nrf2/keap1/HO-1 pathway via keap1 degradation. PRACTICAL APPLICATIONS: In this paper, we investigated the protective effect of SDAPR on APAP-induced AKI in HK-2 cells, and briefly explained its possible mechanism of action, providing a basis for future clinical trials and the development of anti-APAP AKI drugs.