转录因子红系核蛋白的特异转录因子1参与脓毒症小鼠血小板生成减少的调控

Regulation by transcription factor trails - acting factor in globin gene expression and erythriod dif. ferentiaion of platelet production decrease in septic mice

目的观察骨髓巨核细胞成熟障碍是否参与脓毒症血小板减少及转录因子红系核蛋白的特异转录因子1（GATA1）对巨核细胞生成血小板的调控作用。方法将60只BALB／c雄性小鼠随机分为阴性对照（C组）、脓毒症组[大肠杆菌脂多糖（LPS）组]、LPS±地塞米松治疗组（Dex组）。每天检测血小板计数；LPS注射1d细胞涂片染色观察巨核细胞形态，流式细胞术检测巨核细胞表面标记分子CIM1、CD61表达；LPS注射1、3d检测炎性因子白细胞介素（IL）-6、肿瘤坏死因子-α（TNF—α）表达水平，反转录一聚合酶链反应（RT-PCR）检测转录因子GATA1、FOG1 mRNA表达。结果（1）LPS注射1～3dLPS组血小板计数[（334．0±125．7）×10^9／L、（217．0±80．2）×10^9／L、（293．0±27．8）×10^9／L]较C组[（1148．0±56．6）×10^9／L、（1020．0±55．9）×10^9／L、（1158．0±43．8）×10^9／L]明显降低（P〈0．05）；LPS注射1dDex组[（316．0±99．8）×10^9／L]血小板较C组降低（P〈0．05），3d[（401．0±106．1）×10^9／L]较LPS组明显升高（P〈0．05）。（2）LPS注射1d时LPS组、Dex组巨核细胞数较C组升高[07．6±5．7）、（16．9±3．6）、（7．8±2．9）个]，3d时LPS、Dex组巨核细胞数较1d时下降[（12．8±6．4）、（10．5±7．1）个]，但仍高于C组[（8．3±2．0）个，P〈0．05]。LPS组、Dex组巨核细胞胞质体积较C组明显增大，但产血小板型巨核细胞较C组减少（P〈0．05），两组巨核细胞成熟障碍、血小板释放减少；（3）LPS注射1dLPS组与Dex组GATA1、FOG1表达较C组降低（LPS：0．27±0．02、0．61±0．05；Dex：0．22±0．02、0．10±0．01，P〈0．05），LPS组与Dex组GATA1表达差异无统计学意义（P〉0．05），LPS组GATA1与FOG1比较降低更明显（P〈0．05）；LPS注射3d时Dex组GATA1、FOG1表达水平高于LPS组（Dex：0．38±0．02、0．22±0．01；LPS：0．21±0．01、0．20±0．01），两组仍明显低于C组表达（P〈0．05）；（4）LPS注射1d时LPS、Dex组TNF—α、IL-6水平[LPS：（489．3±32．8）、（623．2±25．9）pg／ml；Dex：（468．1±34。9）、（635．1±37．7）pg／m1]较C组[（66．2±23．7）、（78．0±18．6）pg／m]]显著升高，P〈0．01]；3d时各组TNF．or．水平差异无统计学意义（P〉0．05）；LPS组IL-6较C、D组升高[LPS：（222．6±52．3）pg／ml，C组：（81．2±14．5）pg／ml，D组：（98．0±42．5）pg／m]；P〈0．05]，Dex组与C组比较差异无统计学意义（P〉0．05）。结论骨髓巨核细胞成熟障碍是脓毒症时血小板减少的重要原因；LPS可能通过抑制转录因子GATA1表达、抑制巨核细胞成熟而影响血小板生成。Dex通过上调GATA1表达促进巨核细胞成熟、脓毒症时血小板数量。

Objective To investigate the role of trans - acting factor in globin gene expression and erythriod differentiaion （ GATA1 ） in the development of thrombocytopenia in sepsis. Methods Sixty BALB/c male mice were randomly divided into negative control group, sepsis group （LPS group）, LPS ＋ dexamethasone group （ Dex group）. The platelet count was measured every day. The morphyological chan- ges of megakaryocyte in smear staining after one day of LPS injection were observed. The expression levels of inflammatory cytokines interleukin （IL） -6 and tumor necrosis factor - α （TNF - ） were measured af- ter 1 day and 3 days of LPS injection. The levels of GATA1 and friend of GATA1 （ FOGI ） were deteced by reverse transcriptase - polymerase chain reaction （ RT - PCR）, and the experession of megakaryocyte sur- face makers CD41 and C1）61 were examined by flow cytometry. Results （ 1 ） The platelet counts in LPS group [ （334.0 ± 125.7） ×10^9/L, （217.0 ±80. 2） ×10^9/L, （293.0 ±27.8） ×10^9/L] and Dex group [ （316. 0 ±99. 8）×10^9/L, （ 327.0 ± 66. 9）×10^9/L, （401.0 ± 106. 1 ） ×10^9/L] were significantly less than in control group [（1 148.0±56.6）×10^9/L, （1 020.0±55.9） ×10^9/L, （1 158.0±43.8） ×10^9/L] after 1 - 3 days of LPS injection （ P 〈 0. 05 ）. The platelet counts in Dex group were greater than in LPS group （P 〈0. 05） after 2 and 3 days of LPS injection. （2） The expression levels of CD41 and CD61 in bone marrow megakaryocytes of LPS group and Dex group were higher than in control group （ P 〈 0. 05 ） after 24 h of LPS injection. The number of megakaryocytes in LPS group and Dex group was greater than in control group [ （ 17.6 ± 5.7）, （ 16. 9 ± 3.6）, （7.8 ± 2. 9） cells, P 〈 0. 05 ]. The performence of megakaryo- cyte maturation disorder and reduced platelet release were obvious in LPS group and Dex group at high magni- fication. The number of megakaryocytes in LoS group and Dex group after 72 h of LPS injection was less than than after 24 h, but greater than in control group （P 〈 0. 05 ）. （3） The expression of transcription factor GATA1 and FOG1 in LPS group and Dex group was lower than in control group on the first and third day （LPS： 0. 27 ±0. 02, 0. 61 ±0. 05 ;Dex： 0. 22 ±0. 02, 0. 10 ±0. 01 ,P 〈0. 05）. On the third day, the levels of GATAI and FOG1 in Dex group were higher than in LPS group （ P 〈 0. 05 ）. （4） TNF - ct levels [ （489. 3 ±32, 8）, （468.1 ±34. 9） pg/ml] and IL -6 level [ （623.2 ±25. 9）, （635.1 ±37.7） pg/ml]in LPS group and Dex group were significantly higher than in control group [ for TNF - α ： （ 66. 2 ± 23.7 ） pg,/ml, and for IL - 6 ： （78.0 ± 18.6） pg/ml ] after one day of LPS injection （ P 〈 0. 01 ）. IL - 6 level was higher in LPS group [ （220. 6 ± 52. 3 ） pg/ml ] than in control group [ （ 81.2 ± 14. 5 ） pg/ml ] and Dex group [（98.0 ±42.5） pg/ml] after 3 days of LPS injection （P〈0.05）. Conclusion Bone marrow megacaryocyte maturation disorder is the important reason of thrombocytopenia in sepsis. LPS may inhibit the expression of GATA1 and megacaryocyte maturation, whereas influence the formation of plate- lets. Dex promotes megacaryocyte maturation and increases the platelet counts via increasing the expression of GATA1.