Impairment of Spermatogenesis and Sperm Motility by the High-Fat Diet
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Gut microbiota ORIGINAL RESEARCH Gut: first published as 10.1136/gutjnl-2019-319127 on 2 January 2020. Downloaded from Impairment of spermatogenesis and sperm motility by the high- fat diet- induced dysbiosis of gut microbes Ning Ding ,1 Xin Zhang,2 Xue Di Zhang,1 Jun Jing,3,4 Shan Shan Liu,5 Yun Ping Mu,1 Li Li Peng ,6 Yun Jing Yan,1 Geng Miao Xiao,1 Xin Yun Bi,1 Hao Chen,1 Fang Hong Li,1 Bing Yao,3,4 Allan Z Zhao1 ► Additional material is ABSTRact published online only. To view, Objective High- fat diet (HFD)- induced metabolic Significance of this study please visit the journal online disorders can lead to impaired sperm production. We aim (http:// dx. doi. org/ 10. 1136/ What is already known on this subject? gutjnl- 2019- 319127). to investigate if HFD- induced gut microbiota dysbiosis can functionally influence spermatogenesis and sperm ► High- fat diet (HFD) leads to obesity and 1The School of Biomedical motility. metabolic syndromes and affects the functions and Pharmaceutical Sciences, in reproductive system. Guangdong University of Design Faecal microbes derived from the HFD- fed or Technology, Guangzhou, normal diet (ND)- fed male mice were transplanted to the ► HFD- induced gut microbiota dysbiosis and Guangdong, China endotoxaemia have been reported. 2 mice maintained on ND. The gut microbes, sperm count Dizal Pharma, Shanghai, China Emerging evidence demonstrated that gut 3 and motility were analysed. Human faecal/semen/blood ► Jinling Hospital Department microbiota dysbiosis is closely associated Reproductive Medical Center, samples were collected to assess microbiota, sperm Nanjing Medicine University, quality and endotoxin. with a series of major chronic diseases, Nanjing, Jiangsu, China Results Transplantation of the HFD gut microbes such as obesity, diabetes, cancer, IBDs and 4 State Key Laboratory of into the ND- maintained (HFD- FMT) mice resulted in neurodegenerative diseases. Reproductive Medicine, Nanjing Medical University, Nanjing, a significant decrease in spermatogenesis and sperm Jiangsu, China motility, whereas similar transplantation with the 5 Department of Laboratory, microbes from the ND- fed mice failed to do so. Analysis 2 Women and Children ’s Hospital of the microbiota showed a profound increase in treatment to slow down such a trend. The rapid of Qingdao, Qingdao, Shandong, genus Bacteroides and Prevotella, both of which likely decline of semen quality is likely due to the envi- China ronmental factors rather than genetic causes,3 4 such 6 contributed to the metabolic endotoxaemia in the The School of Biology and as environmental toxin, heat, stress,5 smoking,6 Biological Engineering, South HFD- FMT mice. Interestingly, the gut microbes from 7 http://gut.bmj.com/ China University of Technology, clinical subjects revealed a strong negative correlation alcohol consumption and altered dietary struc- Guangzhou, Guangdong, China between the abundance of Bacteroides- Prevotella and tures. Furthermore, with the prevalence of obesity, sperm motility, and a positive correlation between blood the negative impact of fat overaccumulation on Correspondence to endotoxin and Bacteroides abundance. Transplantation male reproduction is gradually recognised in clin- Dr Allan Z Zhao, The School of ical investigations.8–11 In particular, a recent study Biomedical and Pharmaceutical with HFD microbes also led to intestinal infiltration Sciences, Guangdong University of T cells and macrophages as well as a significant involving >10 000 subjects clearly demonstrated of Technology, Guangzhou, increase of pro-inflammatory cytokines in the epididymis, that the sperm quality, including sperm concentra- on September 30, 2021 by guest. Protected copyright. China; azzhao@ gdut. edu. cn suggesting that epididymal inflammation have likely tion, volume and motility, is negatively correlated Dr Bing Yao; with increased body mass index.12 In animal models, yaobing@ nju. edu. cn contributed to the impairment of sperm motility. Dr Fang Hong Li; RNA- sequencing revealed significant reduction in the both genetically inherited and high-fat diet (HFD)- fli@ gdut. edu. cn expression of those genes involved in gamete meiosis induced obesity impaired spermatogenesis.13 14 Dr Hao Chen; and testicular mitochondrial functions in the HFD-FMT Furthermore, HFD could also lead to epigenetic chenhao@ gdut. edu. cn mice. disturbance15 in sperms as paternal inheritance of Received 19 May 2019 Conclusion We revealed an intimate linkage between sperm tsRNAs could induce metabolic disorders in Revised 9 December 2019 HFD- induced microbiota dysbiosis and defect in the F1 offspring.16 Accepted 10 December 2019 spermatogenesis with elevated endotoxin, dysregulation In both humans and animals, the high- fat/high- Published Online First of testicular gene expression and localised epididymal sugar ‘Western’ diet can lead to obesity and meta- 2 January 2020 inflammation as the potential causes. bolic disorders and reshape the gut microbial Trial registration number NCT03634644. ecosystem17 18 comprising trillions of microorgan- isms.19 These microbes in the mammal intestine modulate many physiological functions, such as © Author(s) (or their 20 21 INTRODUCTION harvesting energy, keeping gut integrity, regu- employer(s)) 2020. Re-use 22 23 permitted under CC BY-NC. No Infertility is a global issue that affects as much as lating host immunity and defending patho- 24 25 commercial re-use . See rights 10%–15% of couples in many high- income coun- gens. The perturbation of the ‘healthy’ gut and permissions. Published tries and in countries with improving dietary condi- microbiota may drive the development of a variety by BMJ. tions.1 Approximately half of the infertility can be of chronic diseases, such as obesity,20 26 cancer,22 27 28 To cite: Ding N, Zhang X, attributed to men. Of note, the sperm concentra- IBDs and diabetes. However, it is still unknown Zhang XD, et al. Gut tion has decreased over 50% in Western countries if HFD can impair reproduction through gut micro- 2020;69:1608–1619. from 1973 to 2011 and there is still no effective biota. Herein, we designed a study to delineate the 1608 Ding N, et al. Gut 2020;69:1608–1619. doi:10.1136/gutjnl-2019-319127 Gut microbiota HFD, normal- diet faecal microbiota transplantation (ND- FMT) Significance of this study and high- fat diet faecal microbiota transplantation (HFD- FMT) Gut: first published as 10.1136/gutjnl-2019-319127 on 2 January 2020. Downloaded from groups (six mice per group, three mice per cage). The ND group What are the new findings? and the HFD group were fed with an ND or an HFD (Research ► Transplantation of the faecal microbes derived from HFD- Diet D12451, 45% fat), respectively. Following 4 weeks of fed mice into the male mice maintained on normal diet dietary intervention, the faecal samples collected from either resulted in significant reduction in sperm count and motility, the ND or HFD mice were subsequently transplanted into the which represents the first report of functional impact of gut ND- FMT or HFD- FMT group that were maintained on an ND microbes dysbiosis on fertility. (see ‘Fecal microbiota transplantation experiment’). All mice ► After extensive bioinformatics analysis, we showed that, were sacrificed after 15 weeks of either dietary or FMT interven- at the genus level, the population of two Gram- negative tion for the harvest of serum and tissues. bacteria, Bacteroides and Prevotella, was sharply elevated in the gut transplanted with HFD- microbe. ► Concomitantly, blood endotoxin reached the level of Faecal microbiota transplantation experiment endotoxaemia in the same transplanted mice. Two hundred mg of fresh stool samples were collected from ► Clinically, the abundance of Bacteroides- Prevotella was the ND and HFD group immediately on defaecation and resus- negatively correlated with subjects’ sperm motility, the blood pended in 4 mL of saline, vortexed for 5 min and filtered by endotoxin level was positively correlated with the abundance sterile gauze. The transplantation into the recipient mice was of Bacteroides in the gut. achieved by gavage with 200 µL of the supernatant from the ► A strong negative correlation was found between sperm faecal sample once every 2 days for 15 weeks. motility and high abundance of Prevotella copri (>15% in overall species). Sperm count and motility measurement ► Transplantation and colonisation of the microbes derived The cauda epididymis was minced in 500 L of phosphate buff- from HFD-fed mice caused significant increase in intestinal µ ered saline (pH 7.2) and incubated for 5 min at 37 to release infiltration of CD3+ T cells and macrophages as well as in ℃ the sperm. Sperm motility was measured with a (Hamilton) epididymal pro-inflammatory cytokines, suggesting that equipment. The sperm count was quantified in a haemocytom- endotoxin and epididymal inflammation play important eter (Marienfeld AP-0650030) under a light microscope (Leica roles in gut microbe dysbiosis-induced disruption of DM500). spermatogenesis. How might it impact on clinical practice in the foreseeable future? Histological examination Testes or intestines were removed and fixed in 4% formalin for ► The present study represents the first report in the field of gut microbes to functionally establish the linkage between 24 hours, dehydrated in graded ethanol, embedded in paraffin and sectioned (4 µm in thicknesses). The sections were stained imbalanced gut microbiota and impairment of male fertility, http://gut.bmj.com/ and that some of these gut microbe