OBJECTIVE: To investigate the effect of gender on hepatic pathology and antibody-mediated immunity in Schistosoma japonicum-infected C57BL/6 mice.
METHODS: Female and male C57BL/6 mice were infected with S. japonicum, and the hepatic pathological changes were observed using HE and picrosirius red staining in mice 8 weeks post-infection. The serum specific IgG antibody levels against the soluble adult worm antigen (SWA) and soluble egg antigen (SEA) were measured in mice using enzyme-linked immunosorbent assay (ELISA), and the percentages of follicular helper T (Tfh) cells and regulatory T (Treg) cells were detected in mouse spleen and lymph nodes using flow cytometry.
RESULTS: HE staining showed no significant difference in the mean area of a single hepatic egg granuloma between female and male mice 8 weeks post-infection with S. japonicum [(28.050 ± 3.576) × 104 μm2 vs. (26.740 ± 4.093) × 104 μm2; t = 0.241, P = 0.821], and picrosirius red staining revealed no statistical differences 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 IgG 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 [female 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-infection with 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 the proportion 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-infection 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 significant 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 the lymph 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 was seen between female and male mice 8 weeks post-infection [(17.150 ± 0.805)% vs. (18.550 ± 0.732)%; t = 1.287, P = 0.246].
CONCLUSIONS: There are no gender-specific hepatic pathological changes or antibody-mediated immunity in C57BL/6 mice post-infection with S. japonicum.
[摘要] 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IgG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) × 104 μm2]、雄小鼠肝组织中平均单个虫卵肉芽肿面积 ([ 26.740 ± 4.093) × 104 μm2] 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IgG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。.