重组人生长激素对败血症大鼠肠粘膜屏障功能保护作用的机制研究

目的观察重组人生长激素(RHGH)对败血症大鼠肠粘膜屏障功能的保护作用并探讨其可能的作用机制。方法采用腹腔注射E.COLI复制大鼠败血症模型。42只健康雌性SD大鼠随机分为正常对照组(C组)、败血症组(S组)及RHGH治疗组(T组),S组及T组又依观察时点再分为1D、3D两个亚组(T1D,T3D,S1D,S3D)。应用RT-PCR、免疫组化、放射免疫等方法,动态观测肝组织IGF-1MRNA表达情况、肠粘膜BCL-2蛋白表达水平及细菌移位、血浆生长激素(GH)及胰岛素样生长因子-1(IGF-1)水平及肠道形态等指标的变化情况。结果1RHGH能明显减轻败血症大鼠肠粘膜结构损伤,减轻肠道细菌移位。2T组大鼠肠粘膜BCL-2表达水平(T1D:2441±117;T3D:3628±235)明显高于S组水平(S1D:321±36;S3D:1873±57)(P<0.01)。3T组大鼠血浆GH水平〔T1D:(1.28±0.24)ΜG/L;T3D:(2.14±0.48)ΜG/L〕显著高于S组水平〔S1D:(0.74±0.12)ΜG/L;S3D:(0.60±0.18)ΜG/L〕(P<0.01)。4T组大鼠血浆IGF-1水平〔T1D:(168.94±65.67)ΜG/L;T3D:(201.56±64.98)ΜG/L〕明显高于S组水平〔S1D:(116.72±13.96)ΜG/L;S3D:(107.50±23.53)ΜG/L〕(P<0.05)。5T组大鼠肝IGF-1MRNA表达水平〔T1D:(0.98±0.20);T3D:(1.76±0.17)〕显著高于S组水平〔S1D:(0.38±0.09);S3D:(0.46±0.10)〕(P<0.01)。结论RHGH可能通过抑制肠粘膜上皮细胞凋亡及GH/IGF-1的作用来维护败血症大鼠肠粘膜屏障功能。

Studies of the Possible Mechanisms for Protective Effects of Recombinant Human Growth Hormone on Intestinal Mucosa Barrier in Rat Sepsis

OBJECTIVE: To investigate the protective effects of recombinant human growth hormone (rhGH) on intestinal mucosal barrier in rat sepsis and explore its possible mechanisms. METHODS: E. coli was injected intraperitoneally to produce rats sepsis models. Forty-two female SD rats were randomly divided into the control group (group C), sepsis group (group S) and treatment group (group T). Group S and group T were further divided into 1 d and 3 d subgroups (T1d,T3d, Sld, S3d), respectively. The expression of IGF-1 mRNA in liver, expression of Bcl-2 protein in intestine, bacteria translocation, the levels of growth hormone(GH) and insulin-like growth factor-1 (IGF-1) in plasma, and the histological appearance of intestine were determined dynamically by means of RT-PCR, radioimmunoassay, immunohistochemical staining and other corresponding methods, respectively. RESULTS: (1) rhGH could significantly attenuate intestinal mucosal injuries and ameliorate bacteria translocation on sepsis rats. (2) The levels of Bcl-2 protein expression in intestine in group T (T1d:2441 +/- 117; T3d: 3628 +/- 235) were obviously higher than those of group S (S1d: 321 +/- 36; S3d: 1873 +/- 57) (P < 0.01). (3) The plasma levels of GH in group T (T1d: 1.28 +/- 0.24 microg/L; T3d: 2.14 +/- 0.48 microg/L) increased markedly than those of group S (S1d: 0.74 -/+ 0.12 microg/L; S3d: 0.60 +/- 0.18 microg/L) (P < 0.01). (4) The plasma levels of IGF-1 in group T (Tld: 168.94 +/- 65.67 microg/L; T3d: 201.56 +/- 64.98 microg/L) elevated significantly than those of group S (Sld: 116.72 +/- 13.96 microg/L; S3d:107.50 +/- 23.53 microg/L) (P < 0.05). (5) The levels of liver IGF-1 mRNA in group T (Tld: 0.98 +/- 0.20; T3d: 1.76 +/- 0.17) were significantly higher than those in group S (S1d: 0.38 +/- 0.09; S3d: 0.46 +/- 0.10) (P < 0.01). CONCLUSION: rhGH conferred protective efficacy in maintaining the integrity of intestinal mucosal barrier against sepsis in rat. The possible mechanisms might involve the rhGH-diminished apoptosis of intestinal mucosa cells and the rhGH-maintained intestinal mucosa barrier via the roles of GH and IGF-1.