Pterostilbene exerts a protective effect via regulating tunicamycin-induced endoplasmic reticulum stress in mouse preimplantation embryos

Pterostilbene (PTS) mainly enriched in small fruits such as berries and grapes exerts an antioxidant effect. However, the protective effects of PTS against endoplasmic reticulum stress (ERS) have not yet been elucidated in mouse preimplantation embryo. ERS plays an important role in regulating the pathological and physiological processes, including embryonic development. We explored the protective effect of PTS on the tunicamycin (TM)-induced ERS in mouse preimplantation embryos. In vitro, culture medium was supplemented with different concentrations of TM and PTS. Our result indicated that treatment of zygotes with 0.5 μg/ml TM significantly decreased the development of day 4 blastocysts (P < 0.05), whereas 0.25 μM PTS supplementation improved the development rate of blastocysts. Moreover, TM treatment significantly increased (P < 0.05) the apoptotic index and reduced the total cell number of the blastocyst, whereas PTS treatment counteracted these effects. Additionally, TM potently increased expression levels of ERS-related proteins, such as GRP78, ATF6, PERK, p-Perk, IRE1, ATF4, and CHOP (P < 0.05). However, PTS and PTS + TM treatment decreased expression levels of ERS-related proteins (P < 0.05). Furthermore, expression level of the anti-apoptotic protein and gene BCL2 significantly decreased (P < 0.05) in TM-treated embryo but increased by PTS treatment (P < 0.05), whereas expression levels of the pro-apoptotic protein and gene BAX increased (P < 0.05) with TM but significantly decreased (P < 0.05) with co-treatment with PTS. In summary, PTS treatment significantly increased the development potential of mouse embryo by reduction of ERS.