性别因素对CC57BL/6小鼠日本血吸虫感染所致肝脏病理及抗体免疫的影响

Impact of gender on hepatic pathology and antibody-mediated immunity caused by Schistosoma japonicum infection in C57BL/6 mice

目的探讨性别因素对日本血吸虫感染所致C57BL/6小鼠肝脏病理及抗体免疫的影响。方法雌、雄C57BL/6小鼠分别感染日本血吸虫8周,应用HE染色、天狼星红染色观察小鼠肝脏病理变化。采用酶联免疫吸附试验(ELISA)检测雌、雄C57BL/6小鼠血清抗可溶性成虫抗原(SWA)和可溶性虫卵抗原(SEA)特异性Ig G抗体水平,采用流式细胞术检测雌、雄C57BL/6小鼠脾脏、淋巴结中滤泡辅助性T(Tfh)细胞和调节性T(Treg)细胞水平。结果感染日本血吸虫8周后,雌[(28.050±3.576)×10^4μm^2]、雄小鼠肝组织中平均单个虫卵肉芽肿面积[(26.740±4.093)×10^4μm^2]差异无统计学意义(t=0.241,P=0.821);天狼星红染色结果显示,感染日本血吸虫雌、雄小鼠肝纤维化程度差异亦无统计学意义[天狼星红染色阳性区域平均比例:(7.667±1.856)%vs.(7.667±1.764)%;t=0,P=1;平均光密度:(0.023±0.003)vs.(0.027±0.007);t=0.447,P=0.678]。ELISA检测结果显示,雌、雄小鼠感染日本血吸虫8周后血清抗SWA[(2.098±0.037)vs.(1.970±0.071);t=1.595,P=0.162]和SEA特异性Ig G抗体水平[(3.738±0.039)vs.(3.708±0.043);t=0.512,P=0.623]差异均无统计学意义。流式细胞术检测结果表明,感染日本血吸虫8周后雌、雄小鼠脾脏[雌鼠:(8.645±1.356)%vs.(1.730±0.181)%,t=5.055,P=0.002;雄鼠:(8.470±1.161)%vs.(1.583±0.218)%,t=5.829,P=0.001]、淋巴结[雌鼠:(3.218±0.153)%vs.(1.095±0.116)%,t=11.040,P <0.001;雄鼠:(3.673±0.347)%vs.(0.935±0.075)%,t=8.994,P <0.001]中Tfh细胞比例均显著高于未感染小鼠,但雌、雄小鼠脾脏[(8.645±1.356)%vs.(8.470±1.161)%;t=0.098,P=0.925]和淋巴结[(3.218±0.153)%vs.(3.673±0.347)%;t=1.332,P=0.241]中Tfh细胞比例差异均无统计学意义。感染日本血吸虫8周雄鼠脾脏中Treg细胞比例与未感染小鼠无显著差异[(10.060±0.361)%vs.(10.130±0.142)%;t=0.174,P=0.867],而日本血吸虫感染雌鼠脾脏中Treg细胞比例显著高于未感染小鼠[(10.530±0.242)%vs.(9.450±0.263)%;t=3.021,P=0.023],但感染日本血吸虫雌、雄小鼠脾脏中Treg细胞比例差异无统计学意义[(10.530±0.242)%vs.(10.060±0.361)%;t=1.077,P=0.323];日本血吸虫感染8周后,雌[(17.150±0.805)%vs.(13.100±0.265)%;t=4.781,P=0.003]、雄鼠淋巴结中Treg细胞比例均较未感染小鼠显著增加[(18.550±0.732)%vs.(12.630±0.566)%;t=6.402,P <0.001],但感染日本血吸虫雌、雄小鼠淋巴结中Treg细胞比例差异无统计学意义[(17.150±0.805)%vs.(18.550±0.732)%;t=1.287,P=0.246]。结论利用C57BL/6小鼠研究日本血吸虫感染所致肝脏病理及抗体产生机制时,不需要考虑性别因素。

Objective To investigate the effect of gender on hepatic pathology and antibody-mediated immunity in Schistosoma japonicum-infected C57 BL/6 mice.Methods Female and male C57 BL/6 mice were infected with S. japonicum, and the he-patic pathological changes were observed using HE and picrosirius red staining in mice 8 weeks post-infection. The serum specif-ic Ig G antibody levels against the soluble adult worm antigen(SWA) and soluble egg antigen(SEA) were measured in mice usingenzyme-linked immunosorbent assay(ELISA), and the percentages of follicular helper T(Tfh) cells and regulatory T(Treg) cellswere detected in mouse spleen and lymph nodes using flow cytometry.Results HE staining showed no significant difference inthe mean area of a single hepatic egg granuloma between female and male mice 8 weeks post-infection with S. japonicum [(28.050± 3.576) × 10^4μm^2 vs.(26.740 ± 4.093) × 10^4μm^2;t = 0.241, P = 0.821], and picrosirius red staining revealed no statistical dif-ferences between female and male mice in terms of the mean proportion of picrosirius red stained hepatic tissues [(7.667 ±1.856)% vs.(7.667 ± 1.764)%;t = 0, P = 1] or the mean optical density [(0.023 ± 0.003) vs.(0.027 ± 0.007);t = 0.447, P =0.678]. ELISA detected no significant differences in the serum Ig G antibody levels against SWA [(2.098 ± 0.037) vs.(1.970 ±0.071);t = 1.595, P = 0.162] or SEA [(3.738 ± 0.039) vs.(3.708 ± 0.043);t = 0.512, P = 0.623] between female and male mice 8 weeks post-infection with S. japonicum. Flow cytometry detected significantly greater percentages of Tfh cells in the spleen [fe-male mice,(8.645 ± 1.356)% vs.(1.730 ± 0.181)%, t = 5.055, P = 0.002;male mice,(8.470 ± 1.161)% vs.(1.583 ± 0.218)%, t =5.829, P = 0.001] and lymph nodes [female mice,(3.218 ± 0.153)% vs.(1.095 ± 0.116)%, t = 11.040, P < 0.001;male mice,(3.673 ± 0.347)% vs.(0.935 ± 0.075)%, t = 8.994, P = 0.001) of both female and male mice 8 weeks post-infection with S. japonicum than in uninfected mice;however, no significant differences were seen between female and male mice 8 weeks post-infectionwith S. japonicum in terms of the percentages of Tfh cells in the spleen [(8.645 ± 1.356)% vs.(8.470 ± 1.161)%;t = 0.098, P =0.925] or lymph nodes [(3.218 ± 0.153)% vs.(3.673 ± 0.347)%;t = 1.332, P = 0.241]. There was no significant difference in theproportion of Treg cells in the spleen of male mice between infected and uninfected mice [(10.060 ± 0.361)% vs.(10.130 ±0.142)%;t = 0.174, P = 0.867], while a higher proportion of Treg cells was seen in the spleen of female mice 8 weeks post-infec-tion with S. japonicum than in uninfected mice [(10.530 ± 0.242)% vs.(9.450 ± 0.263)%;t = 3.021, P = 0.023]. There was no sig-nificant difference in the proportion of Treg cells in the spleen between female and male mice infected with S. japonicum [(10.530± 0.242)% vs.(10.060 ± 0.361)%;t =1.077, P = 0.323]. In addition, the proportions of Treg cells were significantly greater in thelymph node of S. japonicum-infected female [(17.150 ± 0.805)% vs.(13.100 ± 0.265)%;t = 4.781, P = 0.003] and male mice[(18.550 ± 0.732)% vs.(12.630 ± 0.566)%;t = 6.402, P = 0.001] than in uninfected mice;however, no significant difference wasseen between female and male mice 8 weeks post-infection [(17.150 ± 0.805)% vs.(18.550 ± 0.732)%;t = 1.287, P = 0.246].ConclusionThere are no gender-specific hepatic pathological changes or antibody-mediated immunity in C57 BL/6 mice post-infection with S. japonicum.