Soy isoflavones protect against oxidative stress and diminish apoptosis in ovary of middle-aged female rats

Abstract

Ovarian aging is characterized by declines in follicular reserve and oocyte quality due, in part, to increased oxidative stress and apoptosis. Soy isoflavones (ISOs) have been shown to improve ovarian lifespan by acting as antioxidant and antiapoptotic agents. We aimed at evaluating whether ISOs could modulate oxidative stress and reduce apoptosis and improve ovarian follicle survival in middle-aged female rats. Twelve ovary-intact female Wistar rats (12-month-old) were divided into groups: control (CTRL) and ISO, daily treated by gavage with vehicle or soy-ISO extract (150 mg/kg b.w), respectively. After 8 weeks, rats were euthanized and their ovaries removed for histomorphometric (% follicles) and apoptosis (cleaved-caspase-3/BCL2 immunostaining) evaluations, or subjected to biochemical assays to survey reactive oxygen species (ROS) and lipid peroxidation levels and total antioxidant capacity (TAC). The frequency of atretic follicles and number of cleaved-caspase-3-positive cells, as well as the ROS and lipid peroxidation levels, were significantly lower in ISO group compared to CTRL. A significantly higher number of BCL2-positive cells and TAC levels were also observed in ISO group. In conclusion, soy ISOs could decrease follicular atresia, apoptosis and oxidative stress, as well as increase the TAC in ovaries of female rats.

摘要

卵巢衰老的特征是卵泡储备和卵母细胞质量下降, 部分原因是氧化应激和细胞凋亡增加。大豆异黄酮（ISOs）已被证明可通过作为抗氧化剂和抗凋亡剂来改善卵巢寿命。我们的目的是评估ISOs是否可以调节氧化应激, 减少细胞凋亡, 改善中年雌性大鼠的卵泡存活率。将12只卵巢完整的雌性Wistar大鼠（12个月大）分组：对照组（CTRL）和ISO组, 每天分别用载体或ISOs提取物（150mg / kg b.w）通过灌胃法进行处理。8周后, 对大鼠实施安乐死并取出卵巢进行组织形态学（％卵泡）和细胞凋亡（切割的caspase-3 / BCL2免疫染色）评估, 或进行生化分析以检测活性氧（ROS）和脂质过氧化水平以及总抗氧化能力（TAC）。与CTRL相比, ISO组中闭锁卵泡的频率和切割的caspase-3阳性细胞的数量以及ROS和脂质过氧化水平显著降低。在ISO组中也观察到显著更高数量的BCL2阳性细胞和TAC水平。总之, ISOs可以减少卵泡闭锁, 细胞凋亡和氧化应激, 以及增加雌性大鼠卵巢中的TAC。

The Chinese abstracts are translated by Prof. Dr. Xiangyan Ruan and her team: Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, China.

Keywords:

• soy isoflavones
• ovarian aging
• oxidative stress
• apoptosis
• rats

Acknowledgments

We would like to thank Mr. Paulo Celso Franco from Department of Morphology and Genetics, Federal University of São Paulo, for technical assistance.

Disclosure statement

No potential conflict of interest was reported by the authors.