Optimizing a Male Reproductive Aging Mouse Model by d-Galactose Injection
1
PhD Program in Nutrition & Food Science, Fu Jen Catholic University, No. 510, Zhongzheng Road, Xinzhuang District, New Taipei City 242, Taiwan
2
Division of Urology, Department of Surgery, Cardinal Tien Hospital, No. 362, Zhongzheng Road, Xindian District, New Taipei City 231, Taiwan
3
School of Medicine, Fu Jen Catholic University, No. 510, Zhongzheng Road, Xinzhuang District, New Taipei City 242, Taiwan
4
Department of Food Science, Fu Jen Catholic University, No. 510, Zhongzheng Road, Xinzhuang District, New Taipei City 242, Taiwan
5
Graduate Institute of Basic Medicine, Fu Jen Catholic University, No. 510, Zhongzheng Road, Xinzhuang District, New Taipei City 242, Taiwan
6
Research Center for Emerging Viral Infections, Chang Gung University, No. 259 Wen-Hwa 1st Road, Kwei-Shan Taoyuan 333, Taiwan
7
Department of Urology, En Chu Kong Hospital, No. 399, Fuxing Road, Sanxia District, New Taipei City 237, Taiwan
8
Department of Chemistry, Fu Jen Catholic University, No. 510, Zhongzheng Road, Xinzhuang District, New Taipei City 242, Taiwan
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Academic Editor: Kenji Murata
Int. J. Mol. Sci. 2016, 17(1), 98; https://doi.org/10.3390/ijms17010098
Received: 9 September 2015 / Revised: 16 December 2015 / Accepted: 28 December 2015 / Published: 13 January 2016
(This article belongs to the Section Biochemistry)
The d-galactose (d-gal)-injected animal model, which is typically established by administering consecutive subcutaneous d-gal injections to animals for approximately six or eight weeks, has been frequently used for aging research. In addition, this animal model has been demonstrated to accelerate aging in the brain, kidneys, liver and blood cells. However, studies on aging in male reproductive organs that have used this animal model remain few. Therefore, the current study aimed to optimize a model of male reproductive aging by administering d-gal injections to male mice and to determine the possible mechanism expediting senescence processes during spermatogenesis. In this study, C57Bl/6 mice were randomized into five groups (each containing 8–10 mice according to the daily intraperitoneal injection of vehicle control or 100 or 200 mg/kg dosages of d-gal for a period of six or eight weeks). First, mice subjected to d-gal injections for six or eight weeks demonstrated considerably decreased superoxide dismutase activity in the serum and testis lysates compared to those in the control group. The lipid peroxidation in testis also increased in the d-gal-injected groups. Furthermore, the d-gal-injected groups exhibited a decreased ratio of testis weight/body weight and sperm count compared to the control group. The percentages of both immotile sperm and abnormal sperm increased considerably in the d-gal-injected groups compared to those of the control group. To determine the genes influenced by the d-gal injection during murine spermatogenesis, a c-DNA microarray was conducted to compare testicular RNA samples between the treated groups and the control group. The d-gal-injected groups exhibited RNA transcripts of nine spermatogenesis-related genes (Cycl2, Hk1, Pltp, Utp3, Cabyr, Zpbp2, Speer2, Csnka2ip and Katnb1) that were up- or down-regulated by at least two-fold compared to the control group. Several of these genes are critical for forming sperm-head morphologies or maintaining nuclear integration (e.g., cylicin, basic protein of sperm head cytoskeleton 2 (Cylc2), casein kinase 2, alpha prime interacting protein (Csnka2ip) and katanin p80 (WD40-containing) subunit B1 (Katnb1)). These results indicate that d-gal-injected mice are suitable for investigating male reproductive aging.
Keywords:
aging; male infertility; mouse model