Application Of Manno-oligosaccharides In The Prevention And Treatment Of Endometritis In Cows

Cow endometritis is the most common reproductive system disease in dairy farms,and bacteria is the main cause of this disease.With the rapid development of dairy farming,the occurrence of endometritis is increasing.At present,the main treatment of endometritis is antibiotics,but the abuse of antibiotics,bacterial resistance is easy to produce,which has a great impact on the development of animal husbandry.Prevention and treatment of endometritis with non-anti-drug has become the focus of current research.As a growth booster,Mannan oligosaccharides(MOS)has been regarded as a potential substitute for antibiotics,which is widely used in the feeding of pigs and poultry and can enhance the body immunity.Our previous studies have shown that MOS can inhibit the inflammatory response of Boss endometrial epithelial cell(BEND)induced by lipopolysaccharide(LPS).Change the expression of Cholesterol 25-hydroxylase(CH25H).In addition,a large number of studies have shown that CH25 H is involved in the body’s inflammatory response.However,it has not been reported whether MOS affects the occurrence of cow endometritis through CH25 H.Therefore,this study first conducted an epidemiological investigation of endometritis in 6 largescale dairy farms in Xianyang area,Shaanxi Province,and explored the effect of MOS on endometritis and the mechanism of action of CH25 H at the cellular and in vivo(mouse)levels respectively,in order to provide theoretical guidance for the clinical application of MOS in dairy industry.The contents and results of this study are as follows:1.Investigate the incidence of endometritis in 6 dairy farms in Xianyang,Shaanxi Province,and make statistics according to month,parity,midwifery and milk production.A total of 24391 dairy cows were investigated in 2021,among which 4267 were diseased,with an average incidence of endometritis of 17.49%.The prevalence of the disease is seasonal,with high incidence in summer and winter.The incidence of endometritis decreased with the increase of parities.The incidence of endometritis increased with the increase of milk production.The incidence of midwifery is higher than that of natural delivery.2.To investigate the role of CH25 H in dairy cow endometritis,LPS(2 μg/m L)and25-hydroxycholesterol,25HC)(50 ng/m L,100 ng/m L)were treated with BEND cells for 6 h,12 h and 24 h to detect the expression levels of related genes and proteins.The results showed that 25 HC significantly increased the cell viability of BEND compared with LPS treatment group(P < 0.05);The m RNA expression levels of Interleukin-1β(IL-1β),Interleukin-6(IL-6),and Interleukin-8(IL-8)were significantly decreased(P< 0.01);Meanwhile,Sterol-regulatory element binding proteins 2(SREBP2),Apoptosis-associated speck-like protein(ASC),absent in melanoma 2(AIM2),apoptosis-associated speck-like protein(ASC),Apoptosis The m RNA,protein and phosphorylation levels of Extracellular regulated protein kinases(ERK1/2)and Protein38(p38)were significantly decreased(P < 0.05).These results suggest that25 HC can inhibit the inflammation of cow endometrial epithelial cells by downregulating the expression of SREBP2 and preventing AIM2 from activating MAPKrelated pathways.3.In order to investigate whether MOS plays an anti-inflammatory role through CH25 H,LPS(2 μg/m L)and MOS(500 μg/m L)were used to treat BEND cells with CH25 H gene(CH25H-/-)knocked down for 6 h,12 h and 24 h to detect the expression levels of related genes and proteins.The results showed that compared with normal group,m RNA expression levels of IL-1β,IL-6 and IL-8 in CH25H-/-group were significantly increased after MOS treatment(P < 0.05);m RNA,protein and phosphorylation levels of SREBP2,ASC,AIM2,ERK1 and p38 were significantly increased(P < 0.05).These results suggest that the inhibitory effect of MOS on the inflammatory response of BEND cells is realized by CH25 H.4.In order to further test whether MOS inhibits the occurrence of endometritis by CH25 H,LPS vaginal perfusion was used in this study to establish a pathological model of mouse endometritis,and different concentrations of MOS(125 μg/m L,250 μg/m L,500 μg/m L)were used for treatment.The results showed that compared with LPS group,the MOS group,Number of White blood cell,lymphocyte,Neutrophile granulocyte,Neutrophilic granulocyte percentage and Red cell distribution width were significantly decreased(P < 0.05,P < 0.01);Both Monocyte(Mon)and Red blood corpuscle numbers were significantly increased(P < 0.01).The levels of Cholesterol Globulin,Albumin/ Globulinand cholesterolwere significantly decreased(P < 0.01).m RNA expression levels of TNF-α,IL-1β,IL-6 and IL-8 were significantly decreased(P <0.05).CH25 H m RNA was significantly increased(P < 0.05).m RNA,protein and phosphorylation levels of ASC,AIM2,SREBP2,ERK1/2 and p38 were significantly decreased(P < 0.05).These results suggest that MOS inhibits mouse endometritis by increasing CH25 H,down-regulating SREBP2 expression,and preventing AIM2 from activating MAPK-related pathways.In summary,MOS inhibits the occurrence of endometritis by altering the expression of CH25 H and inhibiting the activity of SREBP2,thus preventing inflammasome AIM2 from activating MAPK-related pathways.This provides a theoretical basis for the clinical application of MOS in the treatment of cow endometritis.