严重烧伤后早期大鼠肝脏细胞内外钠离子分布和化学状态的变化

目的观察大鼠严重烧伤后肝脏细胞内、外Na 在分布和化学状态上的改变,为烧伤后早期液体复苏方案的选择提供理论指导。方法选取成年雄性SD大鼠19只,随机分为对照组(12只)、烧伤组(7只),采用钠-23磁共振(23NaNMR)波谱技术和位移试剂,测定两组大鼠肝脏细胞内、外Na 的纵向弛豫时间(T1)和横向弛豫时间(T2)的变化。结果输注位移试剂后,烧伤组大鼠肝脏细胞外Na 浓度降低17%,其快T2所占百分比较对照组有所增加(P<0.01),提示细胞外可与Na 结合或可影响Na 的位点增加;细胞内Na 浓度升高了59%,但其弛豫行为却未发生变化。结论烧伤后早期细胞外的Na 可因向细胞内流失或受其周围大分子可逆性结合位点的影响,使瞬时可发挥渗透粒子作用的Na 相对不足,提示烧伤后第1个24h选择适量高钠溶液复苏较合理。

Study on the changes in the distribution and chemical states of the hepatic intra-and extra-cellular sodium ion in the rats with severe burns at early stage

Objective To investigate the changes in the distribution and chemical states of the hepatic intra- and extra-cellular sodium ion in the rats with severe burns,so as to provide guidance for fluid resuscitation at early postburn stage. Methods Nineteen adult male Sprague-Dawley (SD) rats were employed in the study and were randomly divided into control (n=12) and burn (n=7) groups. The changes in the longitudinal (T_1) and transverse (T_2) relaxation times of hepatic intra-cellular and extra-cellular sodium in the two groups were studied with ~ 23 Na NMR spectroscopy and a shift reagent. Results After infusion of the shift reagent,the extra-cellular sodium content in rat liver decreased by 17%, with obvious increase in fast T_2 component (P<0.01), indicating an increase in the fraction of Na~ binding sites in the extra-cellular space. The characteristics of relaxation of intra-cellular sodium remained unchanged despite a 57% increment in intra-cellular sodium content. Conclusion The deficiency of sodium as a permeable molecule might be related to the postburn movement of hypertonic sodium from extra-cellular to intra-cellular space. The results indicatd that it is reasonable to administer high concentration of sodium in fluid resuscitation during the first 24 postburn hours.