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Updated: Apr 3, 2026
Mouse Oocyte Microinjection, Maturation and Ploidy Assessment
Published on: July 23, 2011
No effect of exogenous melatonin on development of cryopreserved metaphase II oocytes in mouse
Wei Li1, Keren Cheng2, Yue Zhang3
1Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University (Chengdu Campus), Wenjiang, 611130 P.R. China ; Institute of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100193 P.R. China.
Background:
This study was conducted to investigate effect of exogenous melatonin on the development of mouse mature oocytes after cryopreservation.
Results:
First, mouse metaphase II (MII) oocytes were vitrified in the open-pulled straws (OPS). After warming, they were cultured for 1 h in M2 medium containing melatonin at different concentrations (0, 10(-9), 10(-7), 10(-5), 10(-3) mol/L). Then the oocytes were used to detect reactive oxygen species (ROS) and glutathione (GSH) levels (fluorescence microscopy), and the developmental potential after parthenogenetic activation. The experimental results showed that the ROS level and cleavage rate in 10(-3) mol/L melatonin group was significantly lower than that in melatonin-free group (control). The GSH levels and blastocyst rates in all melatonin-treated groups were similar to that in control. Based on the above results, we detected the expression of gene Hsp90aa1, Hsf1, Hspa1b, Nrf2 and Bcl-x1 with qRT-PCR in oocytes treated with 10(-7), or 10(-3) mol/L melatonin and untreated control. After warming and culture for 1 h, the oocytes showed higher Hsp90aa1 expression in 10(-7) mol/L melatonin-treated group than in the control (P < 0.05); the Hsf1, Hsp90aa1 and Bcl-x1 expression were significantly decreased in 10(-3) mol/L melatonin-treated group when compared to the control. Based on the above results and previous research, we detected the development of vitrified-warmed oocytes treated with either 10(-7) or 0 mol/L melatonin by in vitro fertilization. No difference was observed between them.
Conclusions:
Our results indicate that the supplementation of melatonin (10(-9) to 10(-3) mol/L) in culture medium and incubation for 1 h did not improve the subsequent developmental potential of vitrified-warmed mouse MII oocytes, even if there were alteration in gene expression.
Insights
Exogenous melatonin did not improve the developmental potential of cryopreserved mouse oocytes. While it altered reactive oxygen species and gene expression, overall outcomes remained unchanged after warming and in vitro fertilization.
Area of Science:
- Reproductive Biology
- Cryobiology
- Molecular Biology
Background:
- Cryopreservation of oocytes is crucial for assisted reproduction.
- Exogenous melatonin's role in protecting oocytes post-cryopreservation requires investigation.
Purpose of the Study:
- To investigate the effect of exogenous melatonin on mouse mature oocytes after cryopreservation.
- To assess melatonin's impact on oocyte quality, gene expression, and developmental potential post-warming.
Main Methods:
- Mouse metaphase II oocytes were vitrified using open-pulled straws.
- Warmed oocytes were cultured in melatonin-supplemented medium (0-10⁻³ mol/L).
- Assessed reactive oxygen species (ROS), glutathione (GSH), gene expression (qRT-PCR), and developmental potential (parthenogenetic activation and in vitro fertilization).
Main Results:
- Melatonin at 10⁻³ mol/L significantly reduced ROS levels and cleavage rates.
- Glutathione levels and blastocyst rates were similar across all groups.
- Gene expression analysis showed varied effects: increased Hsp90aa1 at 10⁻⁷ mol/L, decreased Hsf1, Hsp90aa1, and Bcl-x1 at 10⁻³ mol/L compared to controls.
- In vitro fertilization of vitrified-warmed oocytes showed no difference between melatonin-treated and control groups.
Conclusions:
- Melatonin supplementation (10⁻⁹ to 10⁻³ mol/L) for 1 hour post-warming did not enhance the developmental potential of vitrified-warmed mouse oocytes.
- Observed alterations in gene expression and ROS levels did not translate to improved overall oocyte developmental capacity.
