Objective To explore the feasibility of establishing a tree shrew model of chronic gastrointestinal mucosal injury. Methods A total of 12 adult male tree shrews were randomly divided into 3 groups. The experimental groups 1 and 2 were administered with intraperitoneal injection of 2 mg/(kg·d)and 1 mg/(kg·d)of 1-methyl-4-phenyl-1,2, 3,6-tetrahydropyridine(MPTP)once every day for 56 days, respectively. The control group was given the same volume of sterile saline at the corresponding time points. Changes in the body weight of the tree shrews were observed. The contents of dopamine in the cerebrospinal fluid were detected. Gastrointestinal morphology was observed by stereoscope and histopathological changes of the gastrointestinal mucosa were examined by HE staining. Results The body weight and the contents of dopamine in the cerebrospinal fluid of the tree shrews in the model group were significantly decreased(P< 0.05 for both). Pathological changes to some extent of the gastric antrum, the gastric body and the duodenum were observed, without obvious differences between the 2 mg/kg group and the 1 mg/kg group. No obvious changes were found in the control group. Conclusions Long-term intraperitoneal injection with a low dose of MPTP is a feasible method for the establishment of a tree shrew model of chronic gastrointestinal mucosal injury. The optimal dose is 2 mg/(kg·d)every day for 56 days.

Objective To provide reference values for bone mineral density(BMD)in different skeletal regions of female Wistar rats at different ages. Methods Thirty SPF female Wistar rats were selected. The BMD of different skeletal regions(skull,upper limbs,thighs,trunk,ribs,pelvis,spine and the whole body)was measured by dual energy X-ray absorptiometry(DXA)at 6,10,12,24 and 30 months of age. The bone mineral densities between different age groups and that of different skeletal regions in the same age groups were compared. Results The BMD of the skull,upper limbs,thighs,trunk,ribs,pelvis, spine and the whole body was increased rapidly with age, and reached a peak at 10 months of age. The BMD of the skull,upper limbs,thighs,trunk,ribs were significantly higher than the whole body BMD in the same month-age group(P< 0.05 or P< 0.01). However,there was no significant difference between the pelvic, spine and the whole body BMD(P> 0.05). There was a significant positive correlation among the three correlations(P<0.01). Conclusions Some background data are provided for the bone biology studies of female Wistar rats, and provide useful supplementary reference for the studies of bone metabolism in rats and their application in biomedicine.

Rheumatoid arthritis ( RA ) is a common chronic autoimmune disease .A variety of autoantibodies appears in RA patients and the detection of autoantibodies could be used for the diagnosis and treatment for RA.Anti-citrullinated protein antibodies and rheumatoid factor has been currently used in clinical diagnosis of RA. Recently, a new widely concerned autoantibody , anti-carbamylated protein antibody , is expected to become one of the markers for early diagnosis and evaluation of disease activity and bone destruction.

Objective This study aimed to identify PAX9 variants in non-syndromic tooth agenesis families of Chi-na,as well as to analyze the genotype-phenotype of non-syndromic tooth agenesis caused by PAX9 variants,which can provide a basis for the genetic diagnosis of tooth agenesis.Methods We collected the data of 44 patients with non-syn-dromic oligodontia who underwent treatment at Stomatological Hospital of Hebei Medical University between 2018 and 2023.Whole-exome sequencing was performed on the peripheral blood of the proband and its core family members,and the variants were verified by Sanger sequencing.Pathogenicity analysis and function prediction of the variants were per-formed using bioinformatics tools.The correlation between the genotype of PAX9 variant and its corresponding pheno-type was examined by reviewing 55 publications retrieved from PubMed.The studies involved 232 tooth agenesis pa-tients with PAX9 variants.Results A novel PAX9 c.447delG(p.Pro150Argfs*62)and a reported PAX9 c.406C>T(p.Gln136*)were identified in two Chinese families.Through bioinformatics analysis and three-dimensional structural mod-eling,we postulated that the frameshift variant was pathogenic.The outcome was the premature cessation of PAX9 pro-tein,which caused severe structural and functional deficiencies.Summarizing the PAX9 genotype-phenotype relationship revealed that patients carrying the PAX9 variant commonly led to loss of the second molars.Conclusion We identified the novel PAX9 c.447delG(p.Pro150Argfs*62)in a Chinese family of non-syndromic oligodontia,expanding the known variant spectrum of PAX9.The most susceptible tooth position for PAX9 variants of tooth agenesis was the second mo-lars and the deciduous molars during the deciduous dentition.