Journal of Developmental Medicine(Electronic Version)  2023, Vol. 11 Issue (3): 161-167,173 DOI: 10.3969/j.issn.2095-5340.2023.03.001 |
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| Mechanism of Rankl regulating immune balance of thymus natural regulatory T cells in the rat model of sepsis |
| Wu Chan, Yang Xin, Wang Minrong, et al
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Department of Pediatrics, the First Affiliated Hospital of Chengdu Medical College, Sichuan, Chengdu 610500, China)
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Abstract 【Abstract】 Objective To investigate the immune regulation mechanism of receptor activator of nuclear factor kappa-B ligand (Rankl) on thymus natural regulatory T cells (Treg) in juvenile rats with sepsis. Method The sepsis model of SD male juvenile rats was established by means of lipopolysaccharide (LPS) intra-abdominal injection. 48 rats were divided into 4 groups according to the concentration gradient of LPS, 12 rats in each group were injected with normal saline (control group) and LPS (5, 8, 10 mg/kg). 24 rats were randomly divided into control group, sepsis group, scutellarin (Rankl inhibitor) group and belobulinic acid (NF-κB agonist) group, with 6 rats in each group. Immunohistochemical staining was performed on thymus tissues, and the average optical density of Rankl, autoimmunity regulator (Aire), forkhead box P3 (Foxp3) positive cells was calculated. The protein expression levels of Rankl, nuclear factor kappa-B (NF- κB) p65, Aire and Foxp3 were determined by Western blotting in thymus tissues. One-way analysis of variance and t test were used for statistical analysis. Result In different concentration gradient models, the average optical density of thymus positive cells at 48 hours was compared between the control group and the intraperitoneal injection group of LPS (5, 8, 10 mg/kg) [Rankl: (0.209±0.021)%, (0.256±0.008)%, (0.302±0.015)%, (0.361±0.023)%; Aire: (0.279±0.017)%, (0.350±0.021)%, (0.402±0.013)%, (0.459±0.024)%; Foxp3:(0.207±0.014)%, (0.237±0.010)%, (0.277±0.011)%, (0.310±0.016)%]; so was protein expression (Rankl: 0.577±0.079, 0.740±0.079, 0.935±0.043, 1.240±0.109; NF-κB p65: 0.150±0.064, 0.306±0.055, 0.534±0.077, 0.949±0.077; Aire: 0.324±0.039, 0.571±0.062, 0.737±0.091, 1.019±0.120;Foxp3: 0.226±0.098, 0.475±0.035, 0.824±0.070, 1.148±0.087); LPS modeling groups were higher than control group (all P<0.05). It increased with the increase of LPS dosage, and the increase was most obvious in 10 mg/kg group. Comparison of average optical density of thymus positive cells in sepsis group, scutellarin group and betulinic acid group in different administration models [Rankl: (0.343±0.022)%, (0.262±0.014)%, (0.299±0.020)%; Foxp3: (0.380±0.016)%, (0.340±0.013)%, (0.426±0.012)%; Aire: (0.671±0.079)%, (0.437±0.109)%, (0.893±0.034)%], comparison of protein expression levels (Rankl:0.945±0.059, 0.626±0.072, 0.801±0.052; NF-κB p65: 0.671±0.079, 0.633±0.191, 1.229±0.106; Aire:
0.815±0.144, 0.437±0.109, 1.219±0.114; Foxp3: 0.773±0.093, 0.453±0.143, 1.256±0.086), scutellarin
group was lower than sepsis group, betulinic acid group was higher than sepsis group except Rankl (all
P<0.05). Conclusion In sepsis model, Rankl activates the NF-κB/Aire/Foxp3 signaling pathway to
induce the proliferation of thymus Treg, resulting in immune dysregulation. Rankl inhibitor scutellarin can
regulate the imbalance and produce protective effect on juvenile rats with sepsis.
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Received: 10 January 2023
Published: 30 May 2023
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