Selenium alleviates pancreatic fibrosis in chickens caused by mercuric chloride: Involvement of the MAPK signaling pathway and selenoproteins.

Mercuric chloride (HgCl2) is a widespread inorganic mercury with digestive toxicity. The pancreas is an important digestive organ in animals, and pancreatic fibrosis (PF) is a major pathological feature of chronic pancreatitis, which can be caused by heavy metals. Selenium (Se) is an essential trace element for the animal organism, performing biological functions in the form of selenoproteins, as well as alleviating the toxicity of heavy metals. In this study, we explored the specific mechanisms underlying the protective effect of Se on HgCl2-induced pancreatic injury in chickens. Morphological observation and serum biochemical analysis showed that Se attenuated HgCl2-caused pancreatic tissue damage and elevated glucose concentration and α-amylase activity. Next, the expression of oxidative stress indicators such as MDA and GSH-Px as well as inflammation-related markers including IL-1β, IL-6, and TNF-α were detected. Results showed that Se had an inhibitory effect on HgCl2-induced oxidative stress and inflammation. Furthermore, we found that Se alleviated HgCl2-induced PF by detecting the expression of markers related to PF including TGF-β1, α-SMA, COL1A1, and FN1. Mechanistically, Se attenuated HgCl2-induced PF via the MAPK signaling pathway. Importantly, several selenoproteins, especially those with antioxidant activity, were involved in the protective effect of Se on HgCl2 toxicity. In conclusion, our findings demonstrated that Se inhibited HgCl2-induced oxidative stress and inflammation and alleviated chicken PF through the MAPK signaling pathway, in which some antioxidant selenoproteins were involved.