Semen quality in adult male survivors 5 years after the 2008 Wenchuan earthquake

Lifestyle, Insulin Resistance and Semen Quality as Co-Dependent Factors of Male Infertility

Infertility is a problem that affects millions of couples around the world. It is known as a disease of couples, not individuals, which makes diagnosis difficult and treatment unclear. Male infertility can have many causes, from mechanical ones to abnormal spermatogenesis or spermiogenesis. Semen quality is determined by a number of factors, including those dependent on men themselves, with the number of infertile men growing every year. These include, e.g., diet, physical activity, sleep quality, stress, among many others. As these factors co-exist with insulin resistance, which is a disease closely related to lifestyle, it has been singled out in the study due to its role in affecting semen quality. In order to examine connections between lifestyle, insulin resistance, and semen quality, a review of literature published from 1989 to 2020 in the following databases PubMed/Medline, EMBASE (Elsevier), Scopus, Web of Science, and Google Scholar was performed. Hence, semen quality, environment, and insulin resistance are interrelated, thus it is difficult to indicate which aspect is the cause and which is the effect in a particular relationship and the nature of possible correlations. Since the influence of lifestyle on semen quality has been extensively studied, it is recommended that more thorough research be done on the relationship between insulin resistance and semen quality, comparing the semen quality of men with and without insulin resistance.

LPS-Induced Systemic Inflammation Caused mPOA-FSH/LH Disturbance and Impaired Testicular Function

Male reproductive function is key to the continuation of species and is under sophisticated regulation, challenged by various stressors including inflammation. In the lipopolysaccharide (LPS) intraperitoneal injection-induced acute systemic inflammation, male fecundity was compromised with decreased testosterone level, damaged spermatogenesis, and downregulations of testicular gene expression levels involved in steroidogenesis regulation and blood-testis barrier. It is also noteworthy that the testis is more sensitive to acute stress caused by LPS-induced systemic inflammation. LPS treatment resulted in lower testicular gene expression levels of steroidogenic acute regulatory protein, cholesterol side-chain cleavage enzyme, and cytochrome P450 family 11 subfamily B member 1 after LPS treatment, while no such decrease was found in the adrenal gland. In parallel to the significant decreases in testicular intercellular adhesion molecule 1, tight junction protein 1, and gap junction alpha-1 protein gene expression with LPS treatment, no decrease was found in the epididymis. In the brain, LPS treatment caused higher medial preoptic area (mPOA) activation in the hypothalamus, which is accompanied by elevated blood follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, suggesting a disturbed hypothalamic-pituitary-gonad axis function. Besides mPOA, brain c-fos mapping and quantitative analysis demonstrated a broad activation of brain nuclei by LPS, including the anterior cingulate cortex, lateral septum, paraventricular nucleus of the hypothalamus, basolateral amygdala, ventral tegmental area, lateral habenular nucleus, locus coeruleus, Barrington's nucleus, and the nucleus of the solitary tract, accompanied by abnormal animal behavior. Our data showed that LPS-induced inflammation caused not only local testicular damage but also a systemic disturbance at the brain-testis axis level.