Alternative polarization of resident macrophages improves hyperglycemia-associated male infertility

Role of serotonin, estrogen, and TNF-α in the paroxetine-impaired steroidogenesis and testicular macrophages polarization

BACKGROUND

Paroxetine, a selective serotonin reuptake inhibitor (SSRI) antidepressant, has caused male sexual dysfunction; however, the paroxetine mechanisms of action in testes are still unclear.

OBJECTIVES

Paroxetine serotonergic effects in testes were evaluated, focusing on steroidogenesis and the correlation between macrophages population and possible TNF-α-derived oxidative stress. We also verified whether the changes are reversible following treatment interruption.

MATERIALS AND METHODS

Adult rats received paroxetine (PG35 and PG65) or tap water (CG) for 35 days. PG65 was maintained without treatment for 30 more days. Intratesticular testosterone (IT), nitrite, and malondialdehyde concentrations were measured. To confirm serotonergic and estrogenic effects, Htr1b and Esr1 expressions were analyzed. The daily sperm production (DSP), frequency of abnormal seminiferous tubules (ST), SC number, ST area, and Leydig cells nuclear area (LCnu) were evaluated. TUNEL+ germ cells, M1 (CD68+ ), and M2 (Perls+ ) macrophages were quantified. 17β-HSD7, CYP19A1, NDRG2, oxytocin, TNF-α, and iNOS were evaluated by immunoreactions. Oxytocin and NDRG2 protein levels as well as Tnfa mRNA expression were also analyzed.

RESULTS

The Htr1b downregulation in testes confirmed the paroxetine serotonergic effect. The testicular sections showed abnormal ST frequency, ST atrophy and reduction of DSP, LCnu, SC number and Perls+ macrophages. TUNEL+ germ cells and LC were associated with strong NDRG2 immunoexpression. Paroxetine reduced IT levels and 17β-HSD7 immunoexpression in parallel to increased CYP19A1, oxytocin, TNF-α and iNOS. Esr1 and Tnfa overexpression and increased number of CD68+ macrophages were also observed together with high nitrite and malondialdehyde levels. Most parameters were not recovered in PG65.

CONCLUSIONS

Paroxetine serotonergic effect impairs LC steroidogenesis, via aromatization, increasing estrogen/testosterone ratio, which in turn upregulate NDRG2, promoting apoptosis, and impairing sperm production. Serotonin-estrogen pathways may be responsible for M2/M1 polarization, Tnfa upregulation, and induction of oxidative stress. The unrecovered testicular changes after treatment discontinuation are due to persistent paroxetine serotonin/estrogen effects.

Diabetes-induced male infertility: potential mechanisms and treatment options

Male infertility is a physiological phenomenon in which a man is unable to impregnate a fertile woman during a 12-month period of continuous, unprotected sexual intercourse. A growing body of clinical and epidemiological evidence indicates that the increasing incidence of male reproductive problems, especially infertility, shows a very similar trend to the incidence of diabetes within the same age range. In addition, a large number of previous in vivo and in vitro experiments have also suggested that the complex pathophysiological changes caused by diabetes may induce male infertility in multiple aspects, including hypothalamic-pituitary-gonadal axis dysfunction, spermatogenesis and maturation disorders, testicular interstitial cell damage erectile dysfunction. Based on the above related mechanisms, a large number of studies have focused on the potential therapeutic association between diabetes progression and infertility in patients with diabetes and infertility, providing important clues for the treatment of this population. In this paper, we summarized the research results of the effects of diabetes on male reproductive function in recent 5 years, elaborated the potential pathophysiological mechanisms of male infertility induced by diabetes, and reviewed and prospected the therapeutic measures.