Brown M D, Kent J, Kelsall C J, Milkiewicz M, Hudlicka O
School of Sport & Exercise Sciences, University of Birmingham, Birmingham, UK.
Microcirculation. 2003 Apr;10(2):179-91. doi: 10.1038/sj.mn.7800183.
To establish the time course and extent of remodeling of terminal microcirculation in ischemic rat skeletal muscle during prolonged low flow that does not lead to inflammation.
One common iliac artery was ligated via laparotomy in adult Sprague-Dawley rats and extensor digitorum longus (EDL) muscles removed at intervals (1, 2, and 5 weeks) postsurgery. Serial frozen EDL sections were stained to show capillaries (alkaline phosphatase), cell proliferation (antibody to proliferating cell nuclear antigen [PCNA]), terminal microvessels (antibodies to alpha-smooth muscle actin (alpha-SMA) or endothelial nitric oxide synthase [eNOS]), and macrophages (antibodies to infiltrating and resident macrophages). Total muscle eNOS protein was quantified by standard Western blotting techniques.
Capillary proliferation was very limited in ischemic EDLs, with a modest 12% increase in the capillary/fiber ratio after 5 weeks, preceded at 2 weeks by increased numbers of PCNA-positive nuclei at capillary sites. There was no muscle necrosis or evidence of inflammation, based on macrophage staining. The number of terminal microvessels that were positive for alpha-SMA and <10 microm in diameter was fewer in ischemic EDLs at all time points, whereas the number of larger positive vessels was unchanged. eNOS-positive vessels <10 microm in diameter were stained similarly throughout ischemic muscles as the controls, and showed a similar increase in vessel/fiber ratio as the capillaries. The total eNOS protein level was similar to that in controls in ischemic EDLs after 1 and 2 weeks, but was 28% lower after 5 weeks.
Prolonged, moderate flow reduction to skeletal muscles does not necessarily lead to inflammation or extensive capillary growth. Based on eNOS staining, the terminal microcirculation remains intact, but the loss of alpha-SMA immunoreactivity may indicate remodeling involving the "deinvestment" of microvessels by smooth muscle.
确定在不导致炎症的长时间低血流情况下，缺血大鼠骨骼肌终末微循环重塑的时间进程和程度。
通过剖腹术结扎成年Sprague-Dawley大鼠的一条髂总动脉，并在术后不同时间间隔（1周、2周和5周）取出趾长伸肌（EDL）。对连续的EDL冰冻切片进行染色，以显示毛细血管（碱性磷酸酶）、细胞增殖（增殖细胞核抗原[PCNA]抗体）、终末微血管（α-平滑肌肌动蛋白[α-SMA]或内皮型一氧化氮合酶[eNOS]抗体）和巨噬细胞（浸润性和驻留性巨噬细胞抗体）。通过标准的蛋白质印迹技术对肌肉总的eNOS蛋白进行定量。
缺血EDL中的毛细血管增殖非常有限，5周后毛细血管/纤维比率仅适度增加12%，在2周时毛细血管部位PCNA阳性核数量增加。基于巨噬细胞染色，没有肌肉坏死或炎症迹象。在所有时间点，缺血EDL中直径<10微米且α-SMA阳性的终末微血管数量较少，而较大的阳性血管数量未改变。直径<10微米的eNOS阳性血管在整个缺血肌肉中的染色与对照组相似，并且与毛细血管一样，血管/纤维比率有类似增加。缺血EDL在1周和2周后总的eNOS蛋白水平与对照组相似，但5周后降低了28%。
骨骼肌长时间适度血流减少不一定会导致炎症或广泛的毛细血管生长。基于eNOS染色，终末微循环保持完整，但α-SMA免疫反应性的丧失可能表明涉及微血管平滑肌“去投资”的重塑。
