Microfluidic devices employing chemo- and thermotaxis for sperm selection can improve sperm parameters and function in patients with high DNA fragmentation.

Conventional sperm processing uses centrifugation has a negative effect on sperm parameters and DNA integrity. We designed and fabricated a novel microfluid device based on chemotaxis and thermotaxis, and compared it with the swim-up method. Twenty normal samples with high DNA fragmentation were included. Each sample was divided into four groups: Group 1, control, Group 2: sperm selection by thermotaxis, Group 3: sperm selection by chemotaxis, and Group 4: sperm selection with thermotaxis and chemotaxis. We used cumulus cells in a microfluid device to create chemotaxis, and, two warm stages to form a temperature gradient for thermotaxis. The spermatozoa were assessed based on the concentration, motility, and fine morphology using Motile Sperm Organelle Morphology Examination, mitochondrial membrane potential (MMP), acrosome reaction (AR), and sperm DNA fragmentation. Concentration (22.40 ± 5.39 vs. 66.50 ± 19.21; p < 0.001) and DNA fragmentation (12.30 ± 3.96% vs. 17.95 ± 2.89%; p < 0.001) after selection in the chemotaxis and thermotaxis microfluid device were significantly lower than control group. The progressive motility (93.75 ± 4.39% vs. 75.55 ± 5.86%, p < 0.001), normal morphology (15.45 ± 2.50% vs. 10.35 ± 3.36, p < 0.001), MMP (97.65 ± 1.81% vs. 94 ± 3.89%, p = 0.02), and AR status (79.20 ± 5.28% vs. 31.20 ± 5.24%, p < 0.001) in the chemotaxis and thermotaxis microfluid device were significantly increased compared to control group. According to these findings, spermatozoa that have penetrated the cumulus oophorus have better morphology and motility, as well as acrosome reactivity and DNA integrity.

Impaired hypothalamic-pituitary-testicular axis activity, spermatogenesis, and sperm function promote infertility in males with lead poisoning.

Lead poisoning is a stealthy threat to human physiological systems as chronic exposure can remain asymptomatic for long periods of time before symptoms manifest. We presently review the biophysical mechanisms of lead poisoning that contribute to male infertility. Environmental and occupational exposure of lead may adversely affect the hypothalamic-pituitary-testicular axis, impairing the induction of spermatogenesis. Dysfunction at the reproductive axis, namely testosterone suppression, is most susceptible and irreversible during pubertal development. Lead poisoning also appears to directly impair the process of spermatogenesis itself as well as sperm function. Spermatogenesis issues may manifest as low sperm count and stem from reproductive axis dysfunction or testicular degeneration. Generation of excessive reactive oxygen species due to lead-associated oxidative stress can potentially affect sperm viability, motility, DNA fragmentation, membrane lipid peroxidation, capacitation, hyperactivation, acrosome reaction, and chemotaxis for sperm-oocyte fusion, all of which can contribute to deter fertilization. Reproductive toxicity has been tested through cross-sectional analysis studies in humans as well as in vivo and in vitro studies in animals.

Identification of suitable combinations of in vitro sperm-function test for the prediction of fertility in buffalo bull.

The present study assessed sperm functional characteristics in the frozen-thawed semen of buffalo bulls and estimated their relationship with field fertility. Frozen semen samples from three different freezing operations each from nine Murrah buffalo bulls were used for the assessment of different sperm functions related to fertilizing potential. Bulls were classified into high (n = 2), medium (n = 5), and low (n = 2) fertile based on adjusted field fertility. The sperm functions estimated included membrane integrity using carboxyfluorescein diacetate-propidium iodide, acrosome reaction status using fluorescein isothiocyanate peanut agglutinine, status of apoptosis using Annexin-V, protamine deficiency using Chromomycin A3, membrane stability using Merocyanine 540 and lipid peroxidation status using 4, 4-difluoro-4-bora-3a, 4a-diaza-s-indacene. The relationship between the proportion of live acrosome-intact spermatozoa and fertility was positive and significant (r = 0.59; P = 0.001). The proportion of moribund spermatozoa showed a significantly negative correlation with fertility (r = -0.50; P = 0.008). Similarly, the relationship of spermatozoa with unstable membrane (r = -0.51; P = 0.007), necrotic (r = - 0.42; P = 0.028), early necrotic (r = -0.42; P = 0.031), and apoptotic spermatozoa (r = -0.39; P = 0.046) with bull fertility was negative and significant. The correlation between the protamine-deficient spermatozoa and fertility was negative, but not significant. Among different combinations of tests, live acrosome-intact spermatozoa and lipid peroxidation status of spermatozoa revealed high positive correlation with buffalo bull fertility (adjusted R2 = 0.73, C[p] = 0.80). These preliminary findings may help in developing tools for assessing fertility of buffalo bulls, once validated in more animals.

Sperm function test.

With absolute normal semen analysis parameters it may not be necessary to shift to specialized tests early but in cases with borderline parameters or with history of fertilization failure in past it becomes necessary to do a battery of tests to evaluate different parameters of spermatozoa. Various sperm function tests are proposed and endorsed by different researchers in addition to the routine evaluation of fertility. These tests detect function of a certain part of spermatozoon and give insight on the events in fertilization of the oocyte. The sperms need to get nutrition from the seminal plasma in the form of fructose and citrate (this can be assessed by fructose qualitative and quantitative estimation, citrate estimation). They should be protected from the bad effects of pus cells and reactive oxygen species (ROS) (leukocyte detection test, ROS estimation). Their number should be in sufficient in terms of (count), structure normal to be able to fertilize eggs (semen morphology). Sperms should have intact and functioning membrane to survive harsh environment of vagina and uterine fluids (vitality and hypo-osmotic swelling test), should have good mitochondrial function to be able to provide energy (mitochondrial activity index test). They should also have satisfactory acrosome function to be able to burrow a hole in zona pellucida (acrosome intactness test, zona penetration test). Finally, they should have properly packed DNA in the nucleus to be able to transfer the male genes (nuclear chromatic decondensation test) to the oocyte during fertilization.