Laboratory of Animal Physiology and Functional Anatomy, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
J Assist Reprod Genet. 2013 Jun;30(5):623-31. doi: 10.1007/s10815-013-9987-z. Epub 2013 Mar 29.
The effects of astaxanthin (Ax) on the in vitro development of bovine embryos cultured under heat stress were investigated in combination with the assessment of its cellular accumulation and action on mitochondrial membrane potential (ΔΨm).
Bovine ≥8-cell embryos were collected on day 3 after in vitro fertilization and exposed to single (day 4) or repeated (day 4 and 5) heat stress (10 h/day at 40.5 °C). Ax was added into culture medium under the repeated heat stress and blastocyst development was evaluated. The cellular uptake of Ax in embryos was examined using bright-field and confocal laser-scanning microscopy, and high-performance liquid chromatography. The relationship between Ax and mitochondria localization was assessed using MitoTracker dye. The effects of Ax on ΔΨm were investigated using JC-1 dye.
Blastocyst development in the repeated heat stress treatment decreased significantly (P < 0.05) compared with those in single heat stress or normal thermal treatment. The addition of Ax into culture medium did lead to a significant recovery in blastocyst development in the repeated heat-treated group. Ax was detected in cytoplasm of embryos and observed to colocalize with mitochondria. Ax recovered ΔΨm in embryos that was decreased by the heat treatment.
Ax ameliorated the heat stress-induced impairment of blastocyst development. Our results suggest that the direct action of Ax on mitochondrial activity via cellular uptake is a mechanism of the ameliorating effects.
研究虾青素（Ax）对热应激下体外培养牛胚胎发育的影响，并评估其细胞内积累及其对线粒体膜电位（ΔΨm）的作用。
体外受精后第 3 天收集牛≥8 细胞胚胎，分别在第 4 天（单次热应激）或第 4 天和第 5 天（重复热应激）暴露于 40.5°C 的热应激（每天 10 小时）。在重复热应激下向培养基中添加 Ax，评估囊胚发育情况。使用明场和共聚焦激光扫描显微镜以及高效液相色谱法检测胚胎中 Ax 的细胞内摄取情况。使用 MitoTracker 染料评估 Ax 与线粒体定位的关系。使用 JC-1 染料研究 Ax 对 ΔΨm 的影响。
与单次热应激或正常热处理相比，重复热应激处理后囊胚发育显著下降（P<0.05）。在重复热处理组中向培养基中添加 Ax 确实导致囊胚发育显著恢复。Ax 被检测到在胚胎的细胞质中，并观察到与线粒体共定位。Ax 恢复了因热应激而降低的胚胎 ΔΨm。
Ax 改善了热应激引起的囊胚发育损伤。我们的结果表明，Ax 通过细胞内摄取对线粒体活性的直接作用是其改善作用的机制之一。
