The Functional Role Of Grass Carp Tumor Necrosis Factor-α In The Process Of Skin Wound Healing

Tumor necrosis factor-α(TNF-α)is mainly produced by immune cells such as macrophages and neutrophils,and plays an important role in the pathogenesis of inflammation and autoimmune diseases.TNF-α functions through its two specific membrane receptors,Tumor necrosis factor receptor 1(TNFR1,p55)and TNFR2(p75).At the same time,studies have shown that there are soluble forms of TNFR,which compete with membrane receptors to bind TNF-α,thereby blocking TNF-α signaling.Mammalian studies have shown that TNF-α is related to the infiltration of leukocytes at the wound and can promote skin wound healing.However,some studies also suggest that TNF-α amplifies inflammation,which is not conducive to wound repair.Therefore,the function of TNF-α in skin wound repair needs to be further clarified.Due to the numerous microorganisms in the aquatic environment,any destruction of the barrier function of fish skin may lead to the invasion of symbiotic and pathogenic microorganisms.This may cause acute or chronic inflammation of the fish,leading to severe fish diseases and even the death of fish.Therefore,the integrity of the epidermis is vital to the defensive ability of fish.In teleost,TNF-α and its receptor have been isolated and cloned,and its immunomodulatory function has been successively identified,whereas its basic functions in fish skin wound repair is still unclear.Hence,using grass carp skin wound as a research model,effects of TNF-α signaling on the repair process were explored at the individual level.This research can not only enrich the fish TNF-α function,but also provide a quick repair method for fish skin wound.In this thesis,we first detected the protein levels of TNF-α in the location of skin wounds at different time points after injury,to learn the involvement of TNF-α signals in wound repair.Then a proper amount of grass carp recombinant soluble TNFR2 protein(rgcsTNFR2)was injected locally into the skin wound of grass carp to block the early TNF-α signal.(1)The healing rate of the wound area was reduced to increase the healing time.(2)Inflammatory cells and red blood cells were infiltrated among the new epithelial cells.(3)The levels of pro-inflammatory factors IL-8,IL-1β and other genes were further increased.(4)The recruitment of neutrophils in the wound was intensified.(5)The proliferation of acidic mucous cells of wound tissue were decreased.In summary,this thesis first demonstrated the role of TNF-α in the process of skin repair in grass carp and provided clues for the subsequent development of fish wound healing drugs.