Study On Immunotoxicity In Vivo And Macrophage Immune Response In Vitro Of Medical Bovine Collagen Sponge

Medical bovine collagen sponges are used as haemostatic or filling materials due to their biocompatibility,degradability and good haemostatic properties,and are in direct contact with the body’s internal environment.Although collagen itself is biocompatible,it carries the risk of causing an immune response by carrying immunogenicity.The uncertainty of immunogenicity has led to limitations in the clinical use of this type of material.Understanding the potential mechanisms of the body’s immune response to collagen and its clinical significance is essential to expand the clinical application of medical bovine collagen sponges.This study is based on a combination of in vitro macrophage lines and in vivo implantation of medical bovine collagen sponges as a base material,and focuses on the effect of medical bovine collagen sponges on the immune response in vitro and in vivo.(1)The immunotoxic effects of medical bovine collagen sponges on in vivo immunotoxicity were determined by measuring immune organs,immune cells and immunoglobulin indicators in mice through subcutaneous implantation.Compared with the negative control group,the medical bovine collagen sponge did not promote the proliferation of lymphocytes or changes in the ratio of lymphocytes in mice,and the production of immunoglobulins such as IgG and IgM was not detected in the blood.(2)Effect of medical bovine collagen sponge on Raw264.7 macrophage function.The medical bovine collagen sponge promoted macrophage proliferation and reduced apoptosis by increasing the S-phase ratio of Raw264.7 macrophages;the medical bovine collagen sponge not only increased the phagocytic activity of Raw264.7 macrophages,but also increased their vascular endothelial growth factor(VEGF)secretion and promoted angiogenesis.(3)Study of immunomodulation of Raw264.7 macrophages by medical bovine collagen sponge.The medical bovine collagen sponge had no effect on Raw264.7macrophage morphology at rest,but promoted tumour necrosis factor(TNF-α)secretion,and after pretreatment with the medical bovine collagen sponge,it reduced the stimulation of Raw264.7 by LPS,acting as a bidirectional regulator of inflammatory mediators.In conclusion,the medical bovine collagen sponge not only promotes the basic functions of macrophage proliferation,phagocytosis and repair,but also acts as a bidirectional regulator of Raw264.7 macrophage inflammatory factors,and is less immunostimulatory and biocompatible to the body.The results obtained from these studies improve our understanding of the potential mechanisms of tissue repair in medical bovine collagen sponges and the knowledge of the impact of this material on the local inflammatory environment.