Mouse early blastocysts were exposed to temperatures of 39℃ and 41℃ for 2 h, respectively, to determine their developmental competence and ultrastructural changes. The results showed that heat stress at 41 ℃ for 2 ...Mouse early blastocysts were exposed to temperatures of 39℃ and 41℃ for 2 h, respectively, to determine their developmental competence and ultrastructural changes. The results showed that heat stress at 41 ℃ for 2 h, significantly reduced the percentages of expanded and hatched blastocysts, but not at 39℃ for 2 h. The average cell numbers in expanded blastocysts, which developed from early blastoeysts heat-stressed at temperatures of 39℃ and 41 ℃, were significantly reduced. The average cell numbers in hatched blastocysts subjected to heat stress were no different from those in the control group cultured at 37 ℃ . The mitochondria of the early blastocysts heat-stressed at 39℃ for 2 h, were slightly swollen, but they had recovered after culturing at 37 ℃ for 2 h. However, the mitochondria in the blastocysts heat stressed at 41 ℃ for 2 h were severely swollen, and their number increased. The ribosomes shed from the rough endoplasmic reticulum, and the number of secondary lysosomes in the plasma increased. The integrity of desmosomes was disrupted. The space between the nuclear envelope and the perivitelline membrane enlarged. The fibre fraction and the particulate fraction of nueleoli were separated. The heterochromatin in nueleoli was also increased in its quantity. There were some lamellar-shape structures and heterogeneous dense materials exhibiting in the cytoplasm. The ultrastructural changes induced by heat shock at 41 ℃ for 2 h were not reversible. In conclusion, the damage of heat stress to mitoehondria, lysosomes, ribosomes and cell nucleus, may be one of the most important factors that inhibit the normal development of mouse early blastoeysts .展开更多
基金funded by National Natural Science Fundation of China(No.30571338)
文摘Mouse early blastocysts were exposed to temperatures of 39℃ and 41℃ for 2 h, respectively, to determine their developmental competence and ultrastructural changes. The results showed that heat stress at 41 ℃ for 2 h, significantly reduced the percentages of expanded and hatched blastocysts, but not at 39℃ for 2 h. The average cell numbers in expanded blastocysts, which developed from early blastoeysts heat-stressed at temperatures of 39℃ and 41 ℃, were significantly reduced. The average cell numbers in hatched blastocysts subjected to heat stress were no different from those in the control group cultured at 37 ℃ . The mitochondria of the early blastocysts heat-stressed at 39℃ for 2 h, were slightly swollen, but they had recovered after culturing at 37 ℃ for 2 h. However, the mitochondria in the blastocysts heat stressed at 41 ℃ for 2 h were severely swollen, and their number increased. The ribosomes shed from the rough endoplasmic reticulum, and the number of secondary lysosomes in the plasma increased. The integrity of desmosomes was disrupted. The space between the nuclear envelope and the perivitelline membrane enlarged. The fibre fraction and the particulate fraction of nueleoli were separated. The heterochromatin in nueleoli was also increased in its quantity. There were some lamellar-shape structures and heterogeneous dense materials exhibiting in the cytoplasm. The ultrastructural changes induced by heat shock at 41 ℃ for 2 h were not reversible. In conclusion, the damage of heat stress to mitoehondria, lysosomes, ribosomes and cell nucleus, may be one of the most important factors that inhibit the normal development of mouse early blastoeysts .
