[ ABSTRACT] AIM: To pan the active peptides which specifically bound to the first and second extracellular membrane loops of rat CC chemokine receptor 5 ( CCR5 ) .METHODS: The technique of phage display peptide library was used and binding ability of the peptides was identified.The amino acid sequences of the first and second extracellular loops of rat CCR5 were searched in the protein database and chemically synthesized corresponding linear peptides were used as targets in the biopanning.After 3 to 4 rounds of screening with Ph.D.TM-7 Phage Display Peptide Library were per-formed, the specific phages were collected and primarily identified by ELISA.RESULTS:The sequences of the peptides displayed on the selected phages were GHWKVWL and HYIDFRW, both of them exhibited positive in phage binding ELISA and the binding to phages and targets were concentration dependent and saturable.CONCLUSION:Two antagonis-tic active peptides specifically binding to CCR5 were successfully obtained by the technique of phage display peptide librar-y, and the binding ability to the first and second extracellular membrane loops of rat CCR5 were proved in vitro.

AIM:To analyze the expression of CCR5 and correlation with the expression ofβ-arrestin 2 in the intestinal mucosa of the patients with inflammatory bowel disease ( IBD) , so as to study the role of CCR5 andβ-arrestin 2 in the pathogenesis of IBD.METHODS:Paraffin sections of the colonic mucosa were prepared from 53 patients with active IBD, 26 patients with remissive IBD and 30 healthy people.Immunohistochemical EnVision two-step method was used to test the expression of CCR5 andβ-arrestin 2 in the biopsic intestinal mucosa.RESULTS:The positive rate, strongly posi-tive rate and immunohistochemical score of CCR5 expression in active IBD were significantly higher than those in normal controls or remissive IBD (P<0.05).No correlation of CCR5 expression with clinical severity, lesion distribution, and endoscopic grade in active IBD was observed.The expression ofβ-arrestin 2 was significantly lower in active IBD than that in the remissive IBD and normal controls, and there was a negative correlation ofβ-arrestin 2 expression with CCR5 expres-sion (P<0.05).CONCLUSION:The expression of CCR5 is higher, and expression ofβ-arrestin 2 is lower, and there is a negative correlation of expression of CCR5 with expression ofβ-arrestin 2 in intestinal mucosa of the active IBD.

AIM:To study the effects of antagonistic peptides binding specifically with the first and second extracellular loops (ECL1 and ECL2) of C-C chemokine receptor 5 (CCR5) on the colitis rats induced by trinitrobenzenesulfonic acid (TNBS) and the mechanisms.METHODS:The colitis model of SD rats was induced by TNBS (100 mg/kg).The effects of 2 antagonistic peptides at different doses (ECL1:25, 35 and 45 mg/kg;ECL2:15, 25 and 35 mg/kg) on the model rats including the changes of disease activity index (DAI), colon macroscopic damage index (CMDI) and histological grading were observed.The mRNA and protein expression levels of TNF-α and COX-2 in the colonic mucosa were detected by real-time PCR and Western blot, respectively.RESULTS:Compared with model group, the changes of DAI, CMDI and histopathological injury of the rats treated with ECL2 antagonistic peptide HY at an appropriate dose were significantly reduced (P<0.05), and the protein and mRNA expression levels of TNF-α and COX-2 were significantly decreased (P<0.05).However, the effects of ECL1 antagonistic peptide GH on all scores and the expression levels of TNF-α and COX-2 were not obvious.CONCLUSION:ECL2 antagonistic peptide HY relieves TNBS-induced colitis in SD rats via down-regulating the expressions of TNF-α and COX-2 in the colonic mucosa, while the effect of ECL1 antagonist peptide GH was not obvious.

Drug-induced intestinal mucosal injury is a commonly seen adverse event with the exposure to various drugs. During the course of drug therapy, when exacerbation of primary gastrointestinal disease or new onset of gastro-intestinal symptoms occurs, drug-induced injury should be considered. Patients should be evaluated by gastrointestinal endoscopy for confirming the diagnosis. In this article, the etiologic and pathogenic factors, as well as the diagnostic and therapeutic approaches of four commonly seen drug-induced intestinal mucosal injuries, which were caused by nonsteroidal anti-inflammatory drugs, chemotherapeutic agents, immune checkpoint inhibitors and antibiotics were reviewed.

Objective:To investigate the prevalence of norovirus and the correlation between norovirus infection and stool traits and clinical symptoms in children with acute gastroenteritis during 2021-2022.Method:A total of 2 195 anal swab samples were collected from cases of acute gastroenteritis in Beijing Children 's Hospital Affiliated to Capital Medical University from January 2021 to December 2022. PCR fluorescent probe assay was performed to detect norovirus，the clinical information and test results were performed by statistical analysis. Results:The detection rate of norovirus was 19.09%（419/2 195）in 2 195 children. The detection rates of male and female were 17.80%（244/1 371）and 21.24%（175/824），respectively，with statistically significant differences between genders（ χ2=3.945, P<0.05）. The positivity rate of noroviruses was higher in aged 1 month to 3 years［29.09%（64/220）~40.69%（94/231）］，especially in 1 year［40.69%（94/231）］. The norovirus detection rate ranged from 2.44%（2/82）to 35.84%（62/173）in different months，with a high detection rate between January and March，higher in the winter and spring［28.36%（150/529），21.07%（146/693）］，showing a clear seasonal distribution.Clinical symptoms of both vomiting and diarrhea were significantly more common among norovirus positive than negative children，the difference was statistically significant（ χ2=57.29, P<0.05）. Conclusion:In the high incidence season of winter and spring，for infants and young children aged 1 month to 3 years with diarrhea accompanied by vomiting symptoms，especially those aged 1 year，it is recommended to undergo norovirus related testing in time. Early treatment and isolation measures should be taken for diagnosed children to reduce cross infection and prevent outbreaks.

ObjectiveTo investigate the role and mechanism of action of Yinchenhao Decoction in inhibiting ferroptosis of hepatocytes in mice with autoimmune hepatitis. MethodsA total of 18 specific pathogen-free female C57BL/6 mice were selected and divided into normal group， model group， and treatment group using a random number table， with 6 mice in each group. The mice in the model group and the treatment group were injected with concanavalin A （Con A） via the caudal vein to establish a mouse model of autoimmune hepatitis， and those in the normal group were injected with normal saline. The mice in the treatment group were given prophylactic treatment with Yinchenhao Decoction （4.68 g crude drug/kg） by gavage at 14 days before modeling， and Con A was injected after the last gavage. The levels of alanine aminotransferase （ALT）， aspartate aminotransferase （AST）， interferon gamma （IFN-γ）， tumor necrosis factor-α （TNF-α）， iron ion， glutathione （GSH）， reactive oxygen species （ROS）， adenosine triphosphate （ATP）， and malondialdehyde （MDA） were measured； liver index and spleen index were calculated； the expression levels of GPX4 and SLC7A11 were measured； liver histopathological changes were compared between groups. A one-way analysis of variance was used for comparison of normally distributed continuous data between three groups， and the least significant difference t-test was used for further comparison between two groups. ResultsCompared with the normal group， the model group had significant increases in liver index， spleen index， ALT， AST， IFN-γ， TNF-α， iron ion， ROS and MDA （all P<0.05） and significant reductions in the content of GSH and ATP and the protein expression levels of GPX4 and SLC7A11 （all P<0.05）. Compared with the model group， the treatment group had significant reductions in liver index， spleen index， ALT， AST， IFN-γ， TNF-α， iron ion， ROS and MDA （all P<0.05） and significant increases in the content of GSH and ATP and the protein expression levels of GPX4 and SLC7A11 （all P<0.05）. HE staining showed that compared with the normal group， the model group showed massive hepatocyte degeneration and necrosis and inflammatory cell aggregation at the portal area， and compared with the model group， the treatment group had alleviation of liver necrosis and inflammatory infiltration. ConclusionLiver injury induced by Con A may be associated with ferroptosis. Yinchenhao Decoction can increase the protein expression levels of SLC7A11 and GPX4 protein and thus inhibit ferroptosis of hepatocytes induced by Con A.