Chang C C, Shinonaga M, Kuwabara T, Mima T, Shigeno T
Yokohama City University, Japan.
Acta Neurochir Suppl (Wien). 1990;51:145-7. doi: 10.1007/978-3-7091-9115-6_49.
Glucocorticoids have been extensively used to treat brain oedema, but little is known on the mechanisms of steroids in the prevention and resolution of tumour-induced brain oedema. Recently, the mechanism of steroid action is thought to involve synthesis of proteins with antiphospholipase activity called lipocortins. In a previous study, we have demonstrated the efficacy of dexamethasone (DEX) in resolving peritumoural oedema in a rat glioma model. Using the same model, we studied the effect of recombinant human lipocortin I on the resolution of peritumoural oedema. Intracerebral tumours were produced in 6-week-old Wistar rats by implantation of rat glioma C6 cells. In comparison with sham-operated controls, the tumour-implanted animals showed significant increase in the cortical water content, which was reduced by DEX administration to the level in the sham-operated controls. The water content within the tumour was also significantly decreased by DEX treatment. On the other hand, there was no difference in water content between lipocortin-treated and non-treated animals. These findings suggest that tumour-induced brain oedema can be reduced by DEX treatment but not by lipocortin. In conclusion, it is doubtful whether glucocorticoids exert their action in resolving brain oedema by inducing PLA2 inhibitory proteins named lipocortins.
糖皮质激素已被广泛用于治疗脑水肿，但对于类固醇预防和消退肿瘤诱导的脑水肿的机制却知之甚少。最近，类固醇的作用机制被认为涉及合成具有抗磷脂酶活性的蛋白质，即脂皮质素。在之前的一项研究中，我们已经证明地塞米松（DEX）在大鼠胶质瘤模型中消退肿瘤周围水肿的有效性。使用相同的模型，我们研究了重组人脂皮质素I对肿瘤周围水肿消退的影响。通过植入大鼠胶质瘤C6细胞在6周龄的Wistar大鼠中产生脑内肿瘤。与假手术对照组相比，植入肿瘤的动物皮质含水量显著增加，通过给予DEX可将其降低至假手术对照组的水平。DEX治疗也显著降低了肿瘤内的含水量。另一方面，脂皮质素治疗组和未治疗组动物的含水量没有差异。这些发现表明，肿瘤诱导的脑水肿可通过DEX治疗而不是脂皮质素降低。总之，糖皮质激素是否通过诱导名为脂皮质素的PLA2抑制蛋白来发挥消退脑水肿的作用值得怀疑。
