Alvarez G M, Morado S A, Soto M P, Dalvit G C, Cetica P D
Area of Biochemistry, INITRA (Institute of Research and Technology in Animal Reproduction), Executing Unit INPA (Research in Animal Production) UBA-CONICET, School of Veterinary Sciences, University of Buenos Aires, Buenos Aires, Argentina.
Reprod Domest Anim. 2015 Apr;50(2):200-205. doi: 10.1111/rda.12469. Epub 2014 Dec 17.
The aim of this study was to examine the effect of varying intracellular reactive oxygen species (ROS) levels during oocyte in vitro maturation with enzymatic ROS production systems (xanthine + xanthine oxidase or xanthine + xanthine oxidase + catalase), scavenger systems (catalase or superoxide dismutase + catalase) or cysteine on porcine oocyte maturation. Oocyte ROS levels showed an increase when H2O2 or O2∙(-) production systems were added to the culture medium (p < 0.05). On the other hand, the presence of ROS scavengers in the maturation medium did not modify oocyte ROS levels compared with the control after 48 h of maturation, but the addition of cysteine induced a decrease in oocyte ROS levels (p < 0.05). The ROS production systems used in this work did not modified the percentage of oocyte nuclear maturation, but increased the decondensation of sperm head (p < 0.05) and decreased the pronuclear formation (p < 0.05). In turn, the addition of O2∙(-) and H2O2 scavenging systems during in vitro maturation did not modify the percentage of oocytes reaching metaphase II nor the oocytes with decondensed sperm head or pronuclei after fertilization. However, both parameters increased in the presence of cysteine (p < 0.05). The exogenous generation of O2∙(-) and H2O2 during oocyte in vitro maturation would not affect nuclear maturation or later sperm penetration, but most of the spermatozoa cannot progress to form the pronuclei after fusion with the oocyte. The decrease in endogenous ROS levels by the addition of cysteine would improve pronuclear formation after sperm penetration.
本研究的目的是通过酶促活性氧（ROS）产生系统（黄嘌呤+黄嘌呤氧化酶或黄嘌呤+黄嘌呤氧化酶+过氧化氢酶）、清除系统（过氧化氢酶或超氧化物歧化酶+过氧化氢酶）或半胱氨酸，检测猪卵母细胞体外成熟过程中不同细胞内ROS水平的影响。当向培养基中添加H2O2或O2∙(-)产生系统时，卵母细胞ROS水平升高（p<0.05）。另一方面，成熟培养基中ROS清除剂的存在与成熟48小时后的对照组相比，并未改变卵母细胞ROS水平，但添加半胱氨酸可诱导卵母细胞ROS水平降低（p<0.05）。本研究中使用的ROS产生系统未改变卵母细胞核成熟的百分比，但增加了精子头部的去凝聚（p<0.05）并降低了原核形成（p<0.05）。反过来，体外成熟过程中添加O2∙(-)和H2O2清除系统并未改变达到中期II的卵母细胞百分比，也未改变受精后精子头部去凝聚或有原核的卵母细胞百分比。然而，在半胱氨酸存在的情况下，这两个参数均增加（p<0.05）。卵母细胞体外成熟过程中O2∙(-)和H2O2的外源性产生不会影响核成熟或随后的精子穿透，但大多数精子与卵母细胞融合后无法进展形成原核。添加半胱氨酸降低内源性ROS水平可改善精子穿透后的原核形成。
