Cordycepin alleviates necrotic apoptosis of colonic tissue in ulcerative colitis rats by inhibiting RIP1/RIP3/MLKL signaling pathway
Objective:To investigate the mechanism of cordycepin alleviating necrotic apoptosis of colonic tis-sue in ulcerative colitis(UC)rats by inhibiting receptor interacting protein(RIP)1/RIP3/mixed lineage kinase do-main like protein(MLKL)signaling pathway.Methods:Using trinitrobenzene sulfonic acid(TNBS)and ethanol as a combined enema method to create UC model rats,56 successfully modeled rats were randomly divided into mod-el group,cordycepin low(40 mg/kg),high(80 mg/kg)dose groups,and Nec-1(RIP1 inhibitor,0.6 mg/kg)group,with 14 rats in each group;another 14 rats were taken as control group;rats in each group were given cor-responding drug intervention,once a day,for two consecutive weeks.After 24 hours of administration,the gener-al behavioral status of the rats was recorded and the disease activity index(DAI)score was calculated;HE staining was used to observe the histopathological changes of the colon of rats;detection of serum interleukin(IL)-1β,IL-6,tumor necrosis factor(TNF)-α levels in rats by ELISA;TUNEL was used to detect the apoptosis rate of colon tissue in rats;immunohistochemical method was used to detect the positive expression of myeloperoxidase(MPO),epithelial cadherin(E-cadherin),and proliferating cell nuclear antigen(PCNA)in the colon tissue of rats;the expression of cysteine proteinase-8(Caspase-8),RIP1,phosphorylated RIP1(p-RIP1),RIP3,phosphorylated RIP3(p-RIP3),MLKL,and phosphorylated MLKL(p-MLKL)proteins in rat colon tissue were detected by West-ern blotting.Results:In the control group,the rats had normal bowel movements,complete colonic mucosa structure,no ulcers and erosion were observed,lamina propria glands were closely arranged with clear layers,and epithelial cells were arranged regularly without necrosis and degeneration;compared with control group,the body mass of rats in the model group was decreased,there were loose stools and bloody stools,the structure of colon mucosa was damaged obviously,the arrangement of glands in lamina propria was disordered,the gap was wid-ened,epithelial cells were significantly reduced,and inflammatory cell infiltration was obvious,DAI score,serum IL-1β,IL-6,TNF-α,apoptosis rate,positive expression of MPO and PCNA,p-RIP1/RIP1,p-RIP3/RIP3,p-MLKL/MLKL protein ratios in colon tissue were significantly increased(P＜0.05),E-cadherin positive expres-sion and Caspase-8 protein expression in colon tissue were significantly decreased(P＜0.05);compared with model group,the pathological damage degree of colonic tissue of rats in cordycepin low and high dose groups decreased succes-sively,DAI score,serum IL-1β,IL-6,TNF-α,apoptosis rate,positive expression of MPO and PCNA,p-RIP1/RIP1,p-RIP3/RIP3,p-MLKL/MLKL protein ratios in colon tissue were decreased in turn(P＜0.05),E-cadherin posi-tive expression and Caspase-8 protein expression in colon tissue were increased in turn(P＜0.05);there were no significant differences in the degree of colonic histopathological changes and indexes between the Nec-1 group and the cordycepin high dose group(P＞0.05).Conclusion:Cordycepin can reduce the inflammation of rats with UC by inhibiting RIP1/RIP3/MLKL signaling pathway and reduce the necrotizing apoptosis of colonic histiocytes.
cordycepinreceptor interacting proteinmixed lineage kinase domain like proteinulcerative co-litisapoptosis
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