新型内源性气体信号分子硫化氢对低氧性肺血管胶原重塑的影响

目的研究大鼠低氧性肺血管重塑时硫化氢(H2S)对Ⅰ、Ⅲ型胶原蛋白在肺血管壁异常堆积的调节作用,进一步探讨H2S缓解低氧性肺血管重塑的作用机制。方法19只雄性Wistar大鼠随机分为对照组、低氧组、低氧+硫氢化钠(NaHS)组。低氧组和低氧+NaHS组大鼠共低氧21d,低氧+NaHS组大鼠每天低氧前腹腔注射H2S供体NaHS。低氧结束后,测定肺动脉平均压(mPAP),称重右心室(RV)和左心室+室间隔(LV+SP),计算RV/(LV+SP)。亚甲蓝分光光度法测定血浆中H2S含量。免疫组化染色检测Ⅰ、Ⅲ型胶原蛋白,原位杂交检测Ⅰ、Ⅲ型前胶原mRNA在肺血管壁表达。结果(1)与对照组相比,低氧组大鼠mPAP升高46%,RV/(LV+SP)增加41%,血浆H2S含量下降36%(P均<0·01);与低氧组相比,低氧+NaHS组大鼠的mPAP降低31%,RV/(LV+SP)减少24%,血浆H2S含量升高65%(P均<0·01)。(2)各组大鼠肺小型、中型肌性动脉中Ⅰ型胶原蛋白表达的比较:低氧组较对照组分别增加81%、62%(P<0·01);低氧+NaHS组较低氧组分别减少了32%、18%(P<0·01)。(3)各组大鼠肺小型、中型肌性动脉中Ⅰ型前胶原mRNA表达的比较:低氧组较对照组分别增加49%、68%(P<0·01);低氧+NaHS组较低氧组分别减少了31%、33%(P<0·01)。(4)各组大鼠肺小型肌性动脉中Ⅲ型胶原蛋白表达的比较:低氧组较对照组增加84%(P<0·01);低氧+NaHS组较低氧组减少了37%(P<0·01)。低氧组大鼠的肺中型肌性动脉中Ⅲ型胶原蛋白表达较对照组增加38%(P<0·01);但是与低氧+NaHS组相比无明显变化(P>0·05)。(5)各组大鼠肺小型、中型肌性动脉中Ⅲ型前胶原mRNA表达的比较:低氧组较对照组分别增加53%、17%(P<0·01);低氧+NaHS组较低氧组分别减少了45%、33%(P<0·01)。结论在大鼠低氧性肺血管胶原重塑时,H2S能够抑制Ⅰ、Ⅲ型胶原蛋白及其mRNA在肺血管壁的表达,此作用可能是其缓解低氧性肺血管重塑的作用机制之一。

Effect of a new gasotransmitter, hydrogen sulfide, on collagen remodeling of pulmonary artery under hypoxia

OBJECTIVE: To study the modulatory effect of hydrogen sulfide (H(2)S) on the accumulation of collagen type I and type III in the wall of pulmonary small artery during hypoxic pulmonary vascular remodeling. METHODS: Nineteen male Wistar rats were randomly divided into a control group (n = 6), a hypoxic group (n = 7) and a hypoxia + NaHS group (n = 6). Hypoxic challenge was performed everyday for 21 days. NaHS solution was injected peritoneally everyday before hypoxia challenge for rats in the hypoxia + NaHS group. After 21 days of hypoxia, the mean pulmonary artery pressure was measured by pulmonary artery catheterization. The weight ratio of right ventricle to left ventricle + septum RV/(LV + SP)] was also measured. The plasma level of H(2)S was determined by methylene blue spectrophotometric method. The expression of collagen type I and type III in pulmonary small arteries were detected by immunohistochemistry. The expression of procollagen type I and type III mRNA in pulmonary small arteries were detected by in situ hybridization. RESULTS: (1) Compared with the control group, the mPAP increased by 46% (P < 0.01), the weight ratio of RV/(LV + SP) increased by 41% and the plasma level of H(2)S decreased by 36% for rats in the hypoxia group (P < 0.01). Compared with the hypoxia group, the mPAP decreased by 31% (P < 0.01), the weight ratio of RV/(LV + SP) decreased by 24% and the plasma level of H(2)S increased by 65% (P < 0.01) for rats in the hypoxia + NaHS group. (2) Expression of collagen type I in small and median pulmonary arteries of the three groups: compared with rats in the control group, collagen type I expression increased by 81% and 62% respectively for rats in the hypoxia group (P < 0.01); compared with rats in the hypoxia group, the expression decreased by 32% and 18% respectively for rats in the hypoxia + NaHS group (P < 0.01). (3) Expression of procollagen type I mRNA in small and mid pulmonary arteries of the three groups: compared with rats in the control group, the expression increased by 49% and 68% respectively (P < 0.01) for rats in the hypoxia group; compared with rats in the hypoxia group, the expression decreased by 31% and 33% respectively for rats in the hypoxia + NaHS group (P < 0.01). (4) Expression of collagen type III in small pulmonary arteries of the three groups: compared with rats in the control group, the expression increased by 84% for rats in the hypoxia group (P < 0.01); compared with rats in the hypoxia group, the expression decreased by 37% for rats in the hypoxia + NaHS group (P < 0.01). Compared with rats in the control group, the expression of collagen type III in median pulmonary arteries increased by 38% in the hypoxia group (P < 0.01), while there was no significant difference between the hypoxia group and the hypoxia + NaHS group. (5) Expression of procollagen type III mRNA in small and median pulmonary arteries of the three groups: compared with rats in the control group, the expression increased by 53% and 17% respectively (P < 0.01) for rats in the hypoxia group; compared with rats in the hypoxia group, the expression decreased by 45% and 33% respectively for rats in the hypoxia + NaHS group (P < 0.01). CONCLUSIONS: In the process of hypoxic pulmonary vascular collagen remodeling in rats, H(2)S could inhibit the abnormal accumulation of collagen type I and type III in the wall of pulmonary small arteries. This effect may be one of the mechanisms by which H(2)S ameliorates hypoxic pulmonary vascular remodeling.