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目的探讨重组人骨形态发生蛋白-2(rhBMP-2)对内毒素致急性肺损伤后肺动脉压力(PPa)的影响及机制。方法Wistar大鼠随机分成3组,每组20只。对照组(C组):股静脉输注0.9%生理盐水5ml在1.5h内输注完毕;内毒素(LPS)对照组(L组):经股静脉输注生理盐水3ml1h,然后再输注LPS1mg/kg(溶于2ml0.9%生理盐水中),30min内输注完毕;rhBMP-2处理组(LT组):rhBMP-210μg/kg溶于3ml0.9%生理盐水中,经股静脉1h内输注,然后输注LPS(方法如上),并且分别在输注LPS后24h、48h时经留置的静脉导管单次注射rhBMP-24μg/kg。72h时测定各组大鼠PPa,HE染色后显微图像分析系统测量肺小动脉中膜厚度百分比;BrdU、TUNEL染色法分别检测PASMC增殖、凋亡;膜片钳技术检测延迟整流K+通道(KV)活性;逆转录聚合酶链反应(RT-PCR)及免疫印迹(Western-blot)检测KV1.5mRNA与蛋白质表达。结果L组PPa及肺小动脉中膜厚度百分比显著高于C组、LT组(P<0.01);L组PASMC丝分裂指数显著高于C组、LT组(P<0.01),而凋亡指数明显低于LT组(P<0.01);L组延迟整流K+通道(KV)活性及KV1.5mRNA与蛋白表达水平明显低于C组、LT组(均P<0.05)。结论rhBMP-2能抑制肺动脉平滑肌细胞增殖,促进其凋亡,防止了肺血管构型重建进而抑制了内毒素致急性肺损伤后PPa的升高,发生机制可能与其增加延迟整流K+通道活性及上调KV1.5mRNA与蛋白质表达相关。
Objective To investigate the effect and mechanism of recombinant human bone morphogenetic protein-2 (rhBMP-2) on pulmonary arterial pressure (PPa) induced by endotoxin in acute lung injury. Methods Wistar rats were randomly divided into three groups of 20 rats. The rats in control group (group C) received infusion of 5% 0.9% saline solution in femoral vein for 1.5 hours, and the endotoxin (LPS) control group (L group) received normal saline 3ml for 1 hour via femoral vein, / kg (dissolved in 2ml0.9% saline), the infusion was completed within 30min; rhBMP-2 treatment group (LT group): rhBMP-210μg / kg dissolved in 3ml0.9% saline, , Followed by infusion of LPS (method as above), and a single injection of rhBMP-24 μg / kg via an indwelling intravenous catheter 24 h and 48 h after the LPS infusion, respectively. The percentage of medial thickness of pulmonary arterioles was measured by microscopic image analysis system at 72h after PPa and HE staining. The proliferation and apoptosis of PASMC were detected by BrdU and TUNEL staining respectively. The changes of delayed rectifier K + channel (KV) ) Activity. The expression of KV1.5 mRNA and protein was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western-blot. Results The percentages of PPa and pulmonary arterioles in group L were significantly higher than those in group C and LT (P <0.01). The mitotic index of PASMC in group L was significantly higher than that in group C and LT (P <0.01) (P <0.01). The activity of delayed rectifier K + channel and the expression of KV1.5 mRNA and protein in L group were significantly lower than those in C group and LT group (all P <0.05). Conclusions rhBMP-2 can inhibit pulmonary artery smooth muscle cell proliferation and promote its apoptosis, prevent pulmonary vascular remodeling and then inhibit the increase of PPa after acute lung injury induced by endotoxin, which may be related to the increase of delayed rectifier K + channel activity and upregulation KV1.5 mRNA is associated with protein expression.