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Updated: Dec 26, 2025
A Seminiferous Tubule Squash Technique for the Cytological Analysis of Spermatogenesis Using the Mouse Model
Published on: February 6, 2018
Protective effects of nuclear factor erythroid 2-related factor on oxidative stress and apoptosis in the testis of
Jin Feng1, Yuxuan He1, Yulong Shen1
1College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, 730070, Gansu, China.
Abstract:
Oxidative stress disrupts the intracellular redox balance that modulate many signaling pathways, including nuclear factor erythroid 2-related factor 2 (Nrf2)/Keap1 signaling. However, the antioxidant roles of Nrf2 in the testis before adulthood have not been reported. Accordingly, in this study, we aimed to investigate the effects of the Nrf2 antioxidant system on protection of testicular cells against oxidative stress at different stages of development in the testis of mice before adulthood. Male mice (1, 2, 4, and 8 weeks old) were used, and their relative testes weights were calculated. Malondialdehyde (MDA) contents and superoxide dismutase (SOD) activity were detected to evaluate the antioxidant capacity in the testes. Additionally, Nrf2 signaling pathway and mitochondrial apoptotic pathway proteins were evaluated by western blotting, and the localizations of Nrf2, protein gene product (PGP) 9.5, and activated-caspase 3 in testicular cells were examined using immunohistochemistry. The results showed that the activities of caspase-8 and caspase-3 and the number of activated-caspase 3-positive testicular cells per tubule were increased after 1 week of age. Moreover, MDA contents were increased and SOD activity was decreased with age in mouse testes before adulthood. The expression of PGP9.5 was increased, as well as the number of positive testicular cells per tubule. In addition, Nrf2 translocation to the nuclei of testicular cells also increased, accompanied by activation of the Nrf2/Keap1 signaling pathway. Moreover, nuclear factor-κB was inhibited, and the mitochondrial apoptotic pathway was activated in mouse testes before adulthood. Overall, our findings demonstrated that oxidative stress increased with age in mouse testes before adulthood and that oxidative stress could induce apoptosis in testicular cells. However, testicular cells are still in a rapid proliferative state owing to the antioxidant protection of Nrf2. Thus, our study provided new insights into oxidative stress-mediated impairment of spermatogenesis with age in mouse testes before adulthood and evidence for the protective role of Nrf2 in male fertility.
Insights
Oxidative stress increases with age in developing mouse testes, leading to cell apoptosis. However, the nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant system protects testicular cells, supporting male fertility.
Area of Science:
- Reproductive Biology
- Toxicology
- Cellular Biology
Background:
- Oxidative stress disrupts redox balance and impacts signaling pathways like Nrf2/Keap1.
- The antioxidant role of Nrf2 in the pre-adult testis is not well-documented.
Purpose of the Study:
- To investigate the protective effects of the Nrf2 antioxidant system against oxidative stress in developing mouse testes.
- To understand the impact of oxidative stress on testicular cells at different pre-adult developmental stages.
Main Methods:
- Assessed relative testes weights, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity.
- Utilized western blotting to evaluate Nrf2 signaling and mitochondrial apoptotic pathways.
- Employed immunohistochemistry to examine protein localization (Nrf2, PGP9.5, activated-caspase 3).
Main Results:
- Increased caspase activity and apoptosis markers (activated-caspase 3) with age.
- Elevated MDA levels and decreased SOD activity, indicating increased oxidative stress.
- Upregulated Nrf2 translocation and Nrf2/Keap1 pathway activation, alongside inhibited nuclear factor-κB.
- Evidence of mitochondrial apoptotic pathway activation.
Conclusions:
- Oxidative stress escalates with age in pre-adult mouse testes, inducing testicular cell apoptosis.
- The Nrf2 antioxidant system plays a crucial protective role, maintaining testicular cell proliferation.
- Findings offer insights into age-related oxidative stress impairment of spermatogenesis and Nrf2's role in male fertility.
