Lanosterol influences cytoplasmic maturation of pig oocytes in vitro and improves preimplantation development of cloned embryos.
Lanosterol is a precursor of meiosis-activating sterols in the cholesterol biosynthetic pathway and induces a physiological signal that instructs the oocyte to reinitiate meiosis. In this study, we examined the effect of lanosterol on IVM of porcine oocytes, specifically on nuclear maturation, cytoplasmic maturation by investigating intracellular glutathione (GSH) levels and lipid content, embryonic development after parthenogenetic activation and somatic cell nuclear transfer (SCNT), and on gene expression in cumulus cells, oocytes, and SCNT-derived blastocysts. There was no significant difference in nuclear maturation rates between the control and treatment groups (10, 50, and 100 μM of lanosterol added to IVM culture medium). Supplementation with 50-μM lanosterol significantly increased lipid content and GSH levels and decreased reactive oxygen species levels compared with the control. In addition, oocytes treated with 50 μM of lanosterol exhibited significantly increased blastocyst formation rates and total cell numbers after parthenogenetic activation (30.3% and 63.9 vs. 21.6% and 36.5, respectively) and SCNT (18.2% and 53.7 vs. 12.6% and 37.5, respectively), when compared with the control group. Cumulus cells treated with 50 μM of lanosterol showed significantly increased 14α-demethylase, Δ14-reductase, and Δ7-reductase mRNA transcript levels. Significantly increased PPARγ, SREBF1, GPX1, and Bcl-2 and decreased Bax transcript levels were observed in mature oocytes treated with 50 μM of lanosterol compared with the control. SCNT blastocysts derived from 50-μM lanosterol-treated oocytes had significantly higher POU5F1, FGFR2, and Bcl-2 transcript levels than control SCNT-derived blastocysts. In conclusion, supplementation with 50 μM of lanosterol during IVM improves preimplantation development of SCNT embryos by elevating lipid content of oocytes, increasing GSH levels, decreasing reactive oxygen species levels, and regulating genes related to the cholesterol biosynthetic pathway in cumulus cells, to lipid metabolism and apoptosis in oocytes, and their developmental potential and apoptosis in blastocysts.
Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
Sanghoon
S
Lee
Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
Jun-Xue
JX
Jin
Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
Candrani
C
Khoirinaya
Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
Geon A
GA
Kim
Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea; Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang, Kangwon do, Korea. Electronic address: bclee@snu.ac.kr.
Byeong Chun
BC
Lee
D000818:Animals; D001755:Blastocyst / Q000187:drug effects; D019976:Cloning, Organism / Q000662:veterinary*; D003593:Cytoplasm / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D047108:Embryonic Development / Q000187:drug effects*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D059471:In Vitro Oocyte Maturation Techniques / Q000662:veterinary*; D007810:Lanosterol / Q000008:administration & dosage / Q000494:pharmacology*; D013552:Swine / Q000196:embryology*
D007810:Lanosterol
Embryonic development; IVM; Lanosterol; Porcine oocyte; Somatic cell nuclear transfer