Effects Of Hydrogen Sulfide Exposure On Inflammatory Factor And Apoptosis In Broiler Myocardia

Hydrogen sulfide（H₂S）is one of the most important environmental pollutants in life,which is harmful for all kinds of tissues and organs of human and animals.H₂S is also one of the harmful gases in barton,with the rapid development of poultry industry,the control of H₂S in its environment is particularly important.In this study,120 one-day-old Ross 308 broilers were randomly divided into two groups and placed in two different environmental control room: the control group H₂S concentration controlled below 0.5 mg/m3,the experimental group H₂S concentration were 4 ± 0.5 mg/m3（broilers aged 0-3 weeks）and 20 ± 0.5 mg/m3（broilers aged 4-6 weeks）.Both groups were free to eat and drink water.Broilers were euthanized and sampled during the second,fourth and sixth weeks of exposure to H₂S.By detecting the tissue structure,oxidative damage（SOD,CAT,TAOC,MDA,H₂O₂ and NO）,inflammatory factors（TNF-α,NF-κB,COX-2,IL-1β,IL-2,IL-6 and IL-10）,heat shock proteins（Hsp60,Hsp70 and Hsp90）,mitochondrial dynamics-related genes（Drp1,Mff,Opa1 and Mfn1）,the activity of ATPase and apoptosis-related genes（Cyt C,Cas-3,Cas-8,Cas-9,Bax and bcl-2）to assess toxicity mechanism of H₂S on broiler myocardia.The results showed that:1.H₂S exposure can induce the activities of superoxide dismutase（SOD）,catalase（CAT）,total antioxidant capacity（T-AOC）decreased,resulting in decreasing of eliminated the radicals.Thus the contents of malondialdehyde（MDA）,hydrogen peroxide（H₂O₂）and nitric oxide（NO）increased.These results indicated that oxidative stress occurred in broiler myocardia.2.Inflammatory infiltration was observed in broiler myocardium after H₂S exposure,the expression of pro-inflammation factors including IL-2 and IL-10 decreased whereas the expression of antiinflammation factors including IL-1β and IL-6 increased.Besides,the expression of pro-inflammation factors including TNF-α,NF-κB and COX-2 increased in the fourth week after exposing to H₂S and returned to normal at the sixth week after H₂S exposure.At the same time,the expression of Hsps including Hsp60,Hsp70 and Hsp90 increased.These results indicated that H₂S exposure induced inflammation in broiler myocardia,and Hsps had certain protective effect on myocardia.3.Ultrastructure of broiler myocardium after exposure to H₂S gas showed that chromatin agglutination,nuclear membrane shrinkage,mitochondrial ridge degeneration and disappearance and the presence of apoptosis body.Increased apoptotic rate detected by TUNEL kit.Besides,from detecting the expressions of mitochondrial dynamics related genes,we could obtain that H₂S exposure induced mitochondrial fission genes Drp1 and Mff expressions and inhibited mitochondrial fusion genes Opa1 and Mfn1 expressions.The activities of ATPase including Na⁺-K⁺-ATPase,Ca²⁺-ATPase,Mg²⁺-ATPase and Ca²⁺-Mg²⁺-ATPase decreased.Furthermore,H₂S exposure increased the expressions of pro-apoptosis related genes including Cyt C,Cas-3,Cas-8,Cas-9 and Bax expression and decreased the expression of anti-apoptosis related gene bcl-2.These indicated that H₂S can affect ATP production by destroying the dynamic balance of mitochondria,and then induce apoptosis of broiler myocardia.In summary,this experiment showed that H₂S exposure could cause oxidative stress and abnormal expressions of inflammatory factors and Hsps.Besides,H₂S exposure could induce the apoptosis of broiler myocardia by destroying the balance of mitochondrial dynamics.This study provides valuable clues regarding H₂S-induced toxicology and experimental evidences.