. 2018 Dec 13;19(12):4029. doi: 10.3390/ijms19124029

Table 1.

Effect of melatonin on the G1/S transition in parthenogenetic zygotes.

Groups	No. of Oocytes Vitrified	No. of Oocytes Recovered	No. of Oocytes with Normal Morphology (%)	No. of Oocytes Activated	No. of Activated Oocytes Developed to
Groups	No. of Oocytes Vitrified	No. of Oocytes Recovered	No. of Oocytes with Normal Morphology (%)	No. of Oocytes Activated	Zygotes in G1 Phase (%)	Zygotes in S Phase (%)
Control	-	126	126 (100 ± 0) ^a	118	60 (50.85 ± 18.78) ^a	58 (49.15 ± 18.78) ^a
Vitrification	183	171	158 (87.68 ± 8.22) ^b	155	113 (72.91 ± 10.89) ^b	42 (27.09 ± 10.89) ^b
Vitrification + MT	174	163	153 (89.59 ± 5.71) ^b	141	84 (59.58 ± 8.74) ^a	57 (40.42 ± 8.74) ^a

Morphologically normal oocytes were evaluated by visual inspection of the membrane integrity, the zona pellucida (ZP), and any altered appearance of the cytoplasm (e.g., becoming white, colorless, or dispersed). The number of zygotes with nucleolus (S phase) or without nucleolus (G1 phase) was counted at 4 h after oocyte parthenogenetic activation (PA). Mouse MII oocytes from “Vitrification group” were first subjected to vitrification/warming and 1 h of in vitro culture, then to PA followed by in vitro culture of parthenogenetic embryos. During the whole experimental procedure, the other oocytes were treated either with 10⁻⁹ mol/L melatonin (MT) or without MT and vitrification/warming were classified as “Vitrification + MT group” and “Control group”, respectively. The experiment was replicated five times. The rate of oocytes with normal morphology (%) = (No. of oocytes with normal morphology/No. of oocytes recovered) × 100. The rate of zygotes in S stage (%) = (No. of zygotes in S stage/No. of oocytes activated) × 100. The values are shown as mean ± standard deviation (SD). Values with different superscripts (a and b) in the same column differ significantly (p < 0.05).