Multi-centre assessment of nitroblue tetrazolium reactivity in human semen as a potential marker of oxidative stress

Abstract

The nitroblue tetrazolium (NBT) reaction as a tracer of oxidative stress was examined in 707 ejaculates from seven clinics. Semen was initially surveyed by classifying the NBT reaction using a pre-established rank for the Oxisperm® test based on three colourimetric levels: L1, low (n = 141 [20%]); L2, medium (n = 538 [76%]) and L3, high (n = 28 [4%]). L3 was indicative of a high level of superoxide anions. Halosperm® chromatin dispersion assay was used to analyse samples of ejaculates 30 min after ejaculation; no difference was found in DNA fragmentation of L1 or L3; L3 category semen samples incubated for 24 h at 37C showed a significantly faster rate (P < 0.001) of DNA damage than those in L1. The NBT reaction was further characterized in the ejaculates of 100 patients to determine the relative contribution of seminal plasma, spermatozoa, or both. Seminal plasma was the most significant fraction of •O localization, whereas sperm fractions generated detectable reactive oxygen species in only 32% of the ejaculates. Formazan precipitates were primarily associated with the sperm mid-piece and seminal leukocytes; however, not all spermatozoa stained positive to formazan and not all leukocytes presented with equivalent production of superoxide anions.

Chinese newborn screening for the incidence of G6PD deficiency and variant of G6PD gene from 2013 to 2017

“…Those who were first suspected of having G6PD by NBS were further examined by a NBT G6PD/6PGD test (Gosálvez et al, ). The assays were performed according to the manufacturers’ protocols (YZB/0039–2014; Zhongshan Bio‐tech, China and YZB/0829–2011; Micky Med, China).…”

“…Later, it was expanded to other regions of China for its clinical significance in the identification of neonatal jaundice and acute or chronic hemolysis (Kaplan et al, ; Moiz, Nasir, Khan, Kherani, & Qadir, ). In China, the routine assays for G6PD NBS screening are based on the semiquantitative G6PD activity fluorescence test first (Howson et al, ), and then confirmed by nitroblue tetrazolium (NBT) G6PD/6PGD test (Gosálvez et al, ). The semiquantitative G6PD activity test can accurately identify hemizygous males and homozygous females.…”

From Past to Present: The Link Between Reactive Oxygen Species in Sperm and Male Infertility

“…In this case, the main concern is that several tissue reductases, including sperm cytochromes (CP450R and Cb5R) [101,102], can reduce both probes and, therefore, lead to artefactual NAD(P)H-dependent reduction and the generation of O 2 • − by autoxidation [117,118] (Figures 2 and 3). However, despite these consistent factors, many studies have used this approach to indirectly report the presence of O 2 • − in sperm and further correlate it with semen quality [119][120][121], capacitation [122], hyperactivation [123], DNA integrity [120,124,125], apoptosis [120], IVF outcomes [121], among others. Yet, caution and a deep understanding of the limitations of both detection methods must guide the interpretation of these data.…”

Myrciaria dubia “camu camu” flour as a magnetoprotector in male mouse infertility

“…Previous studies in spermatozoa reported application of this salt to measure seminal ROS production as an oxidative stress tracer [Amarasekara et al, 2014;Gos alvez et al, 2017] related to impaired sperm function (mobility and DNA integrity) [Tunc et al, 2010], as well as to evaluate mitochondrial morphology and functionality [Gaczarzewicz et al, 2003;Piasecka et al, 2004;Mukhopadhyay et al, 2008].…”