Preliminary Pharmacodynamic Study Of Selective TNFR1 Antagonist Peptide Hydrostatin-SN10 In The Treatment Of Inflammatory Bowel Disease

Inflammatory bowel disease(IBD)is an idiopathic intestinal inflammatory disease involved in ileum,bowel and colon,the clinical manifestation of which is repeated abdominal pain,diarrhea,abdominal mass,mucous bloody stool,intestinal obstruction,intestinal perforation,body weight loss,etc.,besides different degrees of systemic symptoms.IBD used to appear mostly in western developed countries.The morbidity of IBD has a linear ascending tendency in Asian including China over recent years.IBD has a strong impact on the living quality of patients and it has become a research hotspot in the area of digestive system diseases.However,it has not been any effective drugs for the treatment of IBD clinically so far.This research group obtained an anti-inflammatory active peptide named Hydrostatin-SN10(10AA).Hydrostatin-SN10 was fully selectively combined with TNFR1 but not TNF-? and TNFR2.Based on these results,this study realized the selective modification of Hydrostatin-SN10 by the covalent linkage with the carboxyl of mPEG2000 to obtain PEG-SN10.This topic dicussed the preliminary pharmacodynamics research of Hydrostatin-SN10 for the treatment of IBD using DSS(26~50KDa)induced acute colitis in mice and OXZ indced acute colitis in mice.This study indicated that the model controlled group mice had severe mucosal colitis with significant reduce weight,low spirits,intestinal bleeding and diarrheain DSS induced acute colitis model in mice.Compared with blank controlled group,the disease activity index(DAI)score of model controlled mice was elevated significantly and the body weight of model controlled mice was reduced obviously;we observe and measure the colons of mice after removing them,finding that decrease in length of the colitis tissues(p<0.001)and the increase in spleen index(p<0.001).Pro-inflammatory factor(TNF-??IL-6?IL-1??IFN-?)levels in mice serum were significantly increased and anti-inflammatory factor(IL-10)level was obviously decreased(p<0.05).Compared with model controlled group mice,Hydrostatin-SN10 and PEG-SN10 significantly reduced the activity of myeloperoxidase(MPO)(p<0.001).Relative expression levels of pro-inflammatory cytokines mRNA were significantly in DSS induced colitis tissues.After intraperitoneal injection of Hydrostatin-SN10 and PEG-SN10,the symptoms above of DSS induce mice wererelieved obviously.The tendency of weight loss was slow down in Hydrostatin-SN10 and PEG-SN10 treated mice.Besides,Hydrostatin-SN10 and PEG-SN10 treated mice had less diarrhea,longer colon length(p<0.001),lower spleen index and MPO activity(both p<0.001).This assay demonstrated that Hydrostatin-SN10 and PEG-SN10 which has anti-onflammatory effects has protection on DSS induced acute colitis in mice.The disease symptom of mice treated with Hydrostatin-SN10 and PEG-SN10 was significantly better than model group mice,including body weight loss,DAI,etc.The treatment effect of Hydrostatin-SN10 and PEG-SN10 was roughly equivalent with two positive control drugs.Negative control drugs had no treatment effect in OXZ induced colitis in mice.The decrease of colon length and the increase of spleen index was obviously relieved in Hydrostatin-SN10 and PEG-SN10 treated mice(both p<0.001).By detecting the activity of MPO,we realized that Hydrostatin-SN10 and PEG-SN10 could significantly decrease the number of neutrophils in the lesion of mice(p<0.001).Besides,Hydrostatin-SN10 and PEG-SN10 could significantly reduce the degree of inflammation and lessen the range of disease in mice colon stained with hematoxylin and eosin.Hydrostatin-SN10 and PEG-SN10 could inhibit the relative mRNA expression of pro-inflammatory factor such as TNF-?,IL-6,IL-1?and IFN-? in colon tissue,increasing the expression of IL-10 meanwhile(p<0.001).In conclusion,Hydrostatin-SN10 and PEG-SN10 have obvious therapeutic effect in OXZ induced acute colitis in mice.The preliminary pharmacokinetic study demonstrated that the drug-time curve was not in accordance with typical compartment model strictly after treated with1mg/kg Hydrostatin-SN10 and 5mg/kg PEG-SN10 by i.p.of a single dose.The pharmacokinetic parameters were calculated according to non-compartment model to reflect the pharmacokinetics of Hydrostatin-SN10 and PEG-SN10 in rats was basically of the linear pharmacokinetic characteristic.The area under the concentration-time curve of Hydrostatin-SN10 in 6 normal adult rats after treated with1mg/kg Hydrostatin-SN10 and 5mg/kg PEG-SN10 by i.p.of a single dose was basically positively correlated with dosage of administration and the correlation coefficient was r2=0.9936 and r2=0.9921.Hydrostatin-SN10 and PEG-SN10 both had good pharmacokinetic properties in rats.The peak concentration of drug(Cmax)was86.92±4.584?g/L and 33.071±1.697?g/L respectively.The time to peak(Tmax)was0.833 h.The terminal elimination half-life(t1/2)was 2.18±0.654 h and 3.789±1.368 hrespectively and the area under the concentration-time curve was 74.043 ±17.065ug/L*h and 32.087±6.317ug/L*h.This research preliminary assessed and evaluated the pesticide effect and pharmacokinetics of Hydrostatin-SN10 and PEG-SN10 which were fully selectivelycombined with TNFR1 to provide theoretical and experimental basisof a drug candidate for the treatment of IBD.