Lintault Laura M, Zakrzewska Elzbieta I, Maple Rhonda L, Baer Lisa A, Casey Theresa M, Ronca April E, Wade Charles E, Plaut Karen
Department of Animal Science, University of Vermont, Burlington, USA.
J Appl Physiol (1985). 2007 Jun;102(6):2186-93. doi: 10.1152/japplphysiol.01015.2006. Epub 2007 Feb 22.
Exposure of rat dams to hypergravity during pregnancy is associated with increased pup mortality, reduced food intake, and decreased rates of glucose oxidation and lipogenesis in mammary tissue. We hypothesized that increased pup mortality is due to changes in maternal metabolism and not to reduced food intake of dams. Effects of hypergravity on rate of glucose oxidation and lipogenesis in mammary, liver, and adipose tissue were measured in rat dams centrifuged at 2.0 G [hypergravity (HG)], kept at 1.0 G (control), or fed to match the intake of HG rats (pair fed) from gestation day 11 (G11) until G21 or postpartum day 3 (P3). Body weight, percent body fat, metabolizable energy, and nitrogen balance were significantly less in HG dams compared with controls (P<0.05); however, these factors were not different between HG and pair-fed dams. By P3, 100% of control and pair-fed pups survived, while only 49% of HG pups survived. At G21, rates of glucose oxidation and lipogenesis in mammary and adipose tissue were less in HG than in control and pair-fed dams (P<0.1 and P<0.05). In liver, at G21, the rate of lipogenesis was greater in HG than control and pair-fed dams (P<0.01); at P3, lipogenesis was greater in control than HG and pair-fed dams (P<0.05). Gene expression of ATP citrate lyase, acetyl-CoA carboxylase, and fatty acid synthase increased in liver from pregnancy to lactation in control and pair-fed dams but not HG dams. Thus reduced food intake and body mass due to hypergravity exposure cannot explain the dramatic decrease in HG pup survival.
孕期大鼠母体暴露于超重力环境下，会导致幼崽死亡率增加、食物摄入量减少，以及乳腺组织中葡萄糖氧化和脂肪生成速率降低。我们推测，幼崽死亡率增加是由于母体代谢变化，而非母体食物摄入量减少所致。在妊娠第11天（G11）至G21或产后第3天（P3），对以2.0G离心（超重力（HG））、保持在1.0G（对照）或喂食量与HG大鼠匹配（配对喂食）的大鼠母体，测量超重力对乳腺、肝脏和脂肪组织中葡萄糖氧化和脂肪生成速率的影响。与对照组相比，HG组母体的体重、体脂百分比、可代谢能量和氮平衡显著降低（P<0.05）；然而，这些因素在HG组和配对喂食组母体之间并无差异。到P3时，100%的对照组和配对喂食组幼崽存活，而HG组幼崽仅有49%存活。在G21时，HG组乳腺和脂肪组织中的葡萄糖氧化和脂肪生成速率低于对照组和配对喂食组母体（P<0.1和P<0.05）。在肝脏中，G21时，HG组的脂肪生成速率高于对照组和配对喂食组母体（P<0.01）；在P3时，对照组的脂肪生成速率高于HG组和配对喂食组母体（P<0.05）。在对照组和配对喂食组母体中，从怀孕到哺乳期间，肝脏中ATP柠檬酸裂解酶、乙酰辅酶A羧化酶和脂肪酸合酶的基因表达增加，但HG组母体未增加。因此，由于暴露于超重力环境导致的食物摄入量和体重降低，无法解释HG组幼崽存活率的显著下降。
