骨骼肌转移瘤罕见性机制的实验研究

为分析骨骼肌微环境因素在其转移瘤罕见性中的意义，作者建立了恶性肿瘤向Wistar大鼠骨骼肌血行转移的动物模型，用免疫组化方法进一步分析骨骼肌微血管内皮细胞粘附分子（VCAM－1）的变化，并用噻唑蓝（MTT）法分析新生Wistar大鼠骨骼肌细胞条件培养基（MCM）对不同肿瘤细胞系的体外抑瘤作用。观察到骼动脉注入瘤细胞后，大腿骨骼肌肌束旁结缔组织内偶见瘤细胞团或实验性转移灶形成，肌细胞间无实验性转移灶形成，与相对应的肺内广泛实验性转移瘤形成率比较，P＜0.001。实验组大腿骨骼肌与对照组肺微血管内皮细胞VCAM－1阳性率无显著差异（P＝0.5），变化趋势一致。MCM对Walker256、K562、LS－174－T、PLA801－C及PLA801－D等肿瘤细胞增殖，均具有显著性意义（P＜0.01－0.05），对RGP－2等正常细胞的增殖无抑制作用。对PLA801－D的抑制作用较对PLA801－C更敏感。骨骼肌细胞产生的抑瘤活性物质，可能是临床上骨骼肌转移瘤罕见性现象的关键因素。

EXPERIMENTAL STUDIES ON THE MECHANISMS OF THE RARITY OF METASTASIS TO SKELETAL MUSCLE

To investigate the mechanisms of the rarity of metastasis to skeletal muscles. Animal models of blood-borne metastasis to skeletal muscle and lung were established,VCAM-1 expressions of the microvascular endothelium in these organs were estimated using immunohistochemistry.The effects of skeletal muscle conditioned media(MCM) on several tumor cell lines were tested by MTT assay.Tumor cells or metastatic foci could be seen rarely in the connective tissue beside muscle bundles of the femoral muscles,however, there is no metastatic foci among muscle cells.The difference of metastatic rate between skeletal muscles and lungs was significant(P<0.001).Statistical analysis showed there was no significant difference between the positive rate of VCAM-1 and its changing status in femoral muscles and that in lungs(P≥0.05).The proliferations of Walker256、K562、LS-174-T、PLA801-C and PLA801-D were significantly inhibited when cultured with MCM(P＜0.01～0.05).The proliferation of normal cells(RGP-2) was not affected by MCM.PLA801-D was more sensitive to MCM than PLA801-C. The results revealed that skeletal muscle derived tumor suppressor(s) may play a key role in the mechanism of the rarity of metastases to skeletal muscles.