Abstract
The sterile inflammatory response is an eminent contributor to acetaminophen (APAP)-hepatotoxicity in humans. Recent advances unraveled an axial role of the NLRP3-inflammasome in APAP-post injury inflammation. Nevertheless, the role of signaling events preceded the NLRP3-inflammasome activation, like the transcription factor NF-kappa B and the purinergic receptor P2X7, is still unclear and needs further elucidation. Here, we investigated the pharmacological inhibition of these upstream signaling molecules by celastrol and brilliant blue G (BBG) (separately or simultaneously) in APAP-hepatotoxicity in mice. The results indicated that both celastrol and BBG pretreatments, especially when combined together, curbed APAP-induced hepatocellular injury (ALT, AST and LDH) and death (necrosis and apoptosis). The underlying mechanisms of protection of such combination against APAP-challenge were attributed to their efficient cooperation in: i) preventing the consumption of hepatic antioxidants (reduced glutathione and superoxide dismutase); ii) limiting the overproduction of lipid peroxidation aldehydes (malondialdehyde and 4-hydroxynonenal) and total nitrate/nitrite products; iii) attenuating the inflammatory cells accumulation in the liver, as evidenced by reducing the number of F4/80 positive cells/field in immunostaining and myeloperoxidase activity; iv) reversing the dysregulation in production of pro-inflammatory (TNF-alpha, IL-17A and IL-23) and anti-inflammatory (IL-10) cytokines; and v) enhancing the reparative capacity of injured hepatocytes, as demonstrated by increasing the percentage of PCNA positive hepatocytes per field of immunostaining. In conclusion, this murine study elicits a potential clinical applicability and therapeutic utility of celastrol and BBG combination in human cases of APAP-overdose hepatotoxicity.