USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, United States.
Anim Reprod Sci. 2012 May;132(1-2):50-7. doi: 10.1016/j.anireprosci.2012.04.004. Epub 2012 Apr 13.
We compared myelination of the cerebellum, brain stem, and spinal cord in the largest and smallest pig fetuses within a litter during late gestation. Gilts were killed on Days 92, 100, and 110 of gestation and these neural tissues were obtained from the largest and smallest fetuses in each litter. Myelin basic protein (MBP) mRNA was quantified in each tissue using real time reverse transcriptase polymerase chain reaction (rtPCR). Myelin was recovered from each tissue and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and thin layer chromatography (TLC) was used to measure MBP and lipids, respectively. MBP mRNA increased with advancing gestation in all three tissues examined (P≤0.05) and was less in brain stem of small piglets compared to large piglets (P<0.01). Two coomassie stained protein bands (HMBP and LMBP) were observed by SDS-PAGE. Six prominent lipid bands were obtained by TLC (cholesterol, hydroxy(h)-cerebroside, nonhydroxy(nh)-cerebroside, phosphatidylethanolamine, phosphatidylcholine, and sphingomyelin). Significant day by fetal size interactions for cerebellar MBP and lipids indicated that cerebellar myelination in the smallest fetuses was less compared to the largest fetuses on Days 100 and 110 of gestation. Myelin MBP and lipid obtained from brain stem increased with advancing gestation and LMBP and lipids were less in small piglets compared to large piglets. In contrast, myelination in spinal cord increased with day of gestation but was not different between smallest and largest fetuses. These results confirm that myelination of the cerebellum and brain stem, but not spinal cord, is reduced in small fetuses during late gestation.
我们比较了妊娠晚期一窝中最大和最小仔猪的小脑、脑干和脊髓的髓鞘形成。母猪分别于妊娠第 92、100 和 110 天处死，从小窝中最大和最小的胎儿中获取这些神经组织。使用实时逆转录聚合酶链反应（rtPCR）在每种组织中定量测定髓鞘碱性蛋白（MBP）mRNA。从每种组织中回收髓鞘，并用十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）和薄层色谱（TLC）分别测量 MBP 和脂质。MBP mRNA 在所有三种检查的组织中均随妊娠进展而增加（P≤0.05），并且与大型仔猪相比，小型仔猪的脑干中含量较低（P<0.01）。SDS-PAGE 观察到两条考马斯亮蓝染色的蛋白质带（HMBP 和 LMBP）。TLC 获得 6 个明显的脂质带（胆固醇、羟基（h）脑苷脂、非羟基（nh）脑苷脂、磷脂酰乙醇胺、磷脂酰胆碱和神经鞘磷脂）。小脑 MBP 和脂质的胎龄与胎儿大小的显著相互作用表明，在妊娠第 100 和 110 天，最小胎儿的小脑髓鞘形成与最大胎儿相比明显减少。随着妊娠的进展，从脑干获得的髓鞘 MBP 和脂质增加，与大型仔猪相比，小型仔猪的 LMBP 和脂质较少。相比之下，脊髓的髓鞘形成随胎龄增加而增加，但最小和最大胎儿之间没有差异。这些结果证实，在妊娠晚期，小脑和脑干的髓鞘形成减少，但脊髓的髓鞘形成不受影响。
