OBJECTIVE: To investigate the expression of citrullinated epitopes in articular cartilage protein and whether its expression is sufficient to induce anti-citrullinated protein antibody (ACPA) response in mice. METHODS: The experimental group was treated with different concentrations of lipopolysaccharide (LPS), heat-inactivated bacteria ( and ) or specific monoclonal antibody against type Ⅱ collagen to induce citrullination of articular cartilage protein, with PBS as the control. Immunohistochemistry with the monoclonal antibody ACC4 (IgG1) that specifically binds to the citrullinated epitope of cartilage protein was performed for detecting the expression of citrullinated protein, with ACC1 (IgG2a) as a positive control antibody and L243 (IgG2a) and Hy2.15 (IgG1) as the negative isotype control. In the in vivo experiment, SD rats were subjected to injection of different doses of LPS in the right knee (with PBS as the controls in the left knee), and 3 days later frozen sections were prepared for immunohistochemical detection of the expression of citrullinated protein. Models of collagen-induced arthritis (CIA) established in different mouse strains were observed for incidence and severity of CIA. Serum samples collected from these models and the sera from rheumatoid arthritis patients were examined for anti-citrullinated protein antibody, and immunohistochemistry was performed to detect the expression of citrullinated protein in the cartilage of the mouse. RESULTS: The citrullinated CII epitope-specific antibody ACC4 did not bind to articular cartilage tissues with different treatments as compared with the positive control antibody ACC1. The ACC4 antibody and the antibodies from patients with rheumatoid arthritis with high titers of anti-citrullinated protein antibody were capable of binding to the synovial tissue around the articular cartilage of the CIA. Luminex analysis showed that the anti-citrullinated protein antibody was lowly expressed in mouse serum, but the anti-type Ⅱ collagen triple helix structure peptide antibody exhibited strong reactivity. CONCLUSIONS Mild acute inflammatory response is not enough to cause citrullination of articular cartilage protein, and the expression of specific epitope requires a high-intensity inflammatory response. Inflammatory articular cartilage protein can express citrullinated epitopes in type Ⅱ collagen-induced arthritis in mice, but the expression of citrullinated epitopes is not sufficient to induce an immune response to anti-citrullinated antibodies. Stronger stimulation signals are required to induce an immune response for producing anti-citrullinated protein antibodies.
Animals ; Arthritis, Experimental ; Autoantibodies ; Cartilage, Articular ; Citrulline ; Humans ; Inflammation ; Mice ; Rats ; Rats, Sprague-Dawley

OBJECTIVE To investigate the implementation effects of the national centralized drug volume-based procurement policy （abbreviated as “national centralized procurement policy”） in Guangxi Zhuang Autonomous Region prefecture， and to provide a reference for the future centralized drug procurement work of the medical institution. METHODS Drug procurement data before and after policy implementation were included in the study. The six secondary indicators （such as availability， affordability， and drug safety） and eighteen third-level indicators （such as completion rate of agreed purchase volume， affordability level， drug revenue proportion） were introduced， guided by the policy objectives and issues of concern to policy beneficiaries. Descriptive statistics was adopted to analyze the data before and after policy implementation （in 2019 and 2020） in terms of differences and change trends. RESULTS In terms of accessibility， the participation rate of medical institutions in Guangxi Zhuang Autonomous Region was 92.55%， the proportion of diseases involved and median completed procurement rate were 40.16%， and 287.82% respectively， and the total centralized delivery rate was 97.20%. In terms of affordability， the total reduction amplitude in drug price was 74.80% from 2019 to 2022； the charge for medicine per capita in hospitalization， the proportion of medicine used for outpatient service and hospitalization， decreased by 17.61%， 10.22%， and 20.10% in order； the burden levels on medical fares for patients were all below 1 in addition to chronic diseases， and anti-tumor drugs. In terms of the impact on medicine， the ratio of adverse drug reaction event cases in 2022 was 66.00%， an increase of 1.29% compared to the previous； since the implementation of the policy， 12 drugs from local pharmaceutical enterprises from Guangxi Zhuang Autonomous Region had passed the consistency evaluation， and the market concentration rate of the top 8 pharmaceutical companies was less than 20.00%. In terms of the impact on healthcare and medical insurance， the public medical institutions achieved generic substitution for originator drugs mostly until 2022； about 9.12% of drugs that were non- centrally purchased in the same category were used； 63.39% of people under investigation did not show a need for a second dressing change； drug expenditure decreased by 2.459 billion yuan. CONCLUSIONS The national centralized procurement policy achieves a significant effect in Guangxi Zhuang Autonomous Region. On the other hand， attention should be paid to these suggestions as follows: expanding the category of drugs used in clinic， conducting clinically comprehensive evaluation of selected drugs， and improving reasonable allocation strategy， etc.