Sertoli cell-germ cell communication

Basigin interacts with both MCT1 and MCT2 in murine spermatozoa

Lactate is provided to spermatogenic cells by Sertoli cells as an energy substrate and its transport is regulated by H(+)-monocarboxylate co-transporters (MCTs). In the case of several cell types it is known that MCT1 is associated with basigin and MCT2 with embigin. Here we demonstrate co-localization and co-immunoprecipitation of basigin with both MCT1 and MCT2 in sperm, whereas no interaction with embigin was detectable. An investigation of the functional activity of MCT proteins revealed that it was mainly the application of L-lactate which resulted in a decrease in pH(i) . The pH(i) changes were blocked with α-cyano-4-OH cinnamate and the preference for L-lactate-as opposed to D-Lactate-was demonstrated by the determination of ATP after exposure to both lactate isomers. We propose that basigin interacts with MCT1 and MCT2 to locate them properly in the membrane of spermatogenic cells and that this may enable sperm to utilize lactate as an energy substrate contributing to cell survival.

Increased Total Antioxidant Capacity in Seminal Plasma of Varicocele Patients: A Multivariate Analysis

To investigate seminal antioxidant systems and their correlation with hormonal pattern in varicocele patients, we studied 33 varicocele (VAR) patients (12 oligozoospermic, 21 normozoospermic) and 34 non-VARs (10 idiopathic oligozoospermic, 24 normozoospermic). Non-enzymatic total antioxidant capacity (TAC) was measured using H(2)O(2)-metamyoglobin, which generates the radical form, spectroscopically detectable, of the chromogen 2,2',-azinobis-3-ethylbenzothiazoline-6-sulphonate (ABTS): time till appearance (Lag) of ABTS*(-) signifies antioxidant concentration. Lag was significantly longer in VARs than controls suggesting ineffective utilization of antioxidants. A significant direct correlation (r = 0.65, p < 0.01) of Lag with sperm count was observed in non-VARs, while in VARs it was inverted, as well as with hematic FSH levels. A multivariate analysis including FSH, Lag, progressive spermatozoa, oligozoospermia and varicocele indicated a strong inverse correlation between FSH and motility (r(2) = 0.31, p > F = 0.0007), not modified by Lag (r(2) = 0.31, p > F = 0.002). Their inverse correlation with Lag may suggest that higher FSH levels, improving sperm antioxidant efficiency, counterbalance varicocele-induced dyspermia.

Total antioxidant capacity in patients with varicoceles

OBJECTIVE

To explore a possible molecular defect linked to infertility, studying total antioxidant capacity (TAC) of seminal plasma in varicocele (VAR).

DESIGN

Case-series study.

SETTINGS

Volunteers in an academic research environment and out-patients in clinical service.

PATIENT(S)

Twenty-five VAR patients (9 oligospermic and 16 normospermic) vs 24 non-VAR controls (7 subjects with idiopathic oligospermia and 17 normospermic subjects).

INTERVENTION(S)

Evaluation of seminal plasma TAC.

MAIN OUTCOME MEASURE(S)

TAC was measured using myoglobin, as a source of radicals, which interact with a chromogen 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonate) (ABTS), whose radical cation is spectroscopically detectable. The latency phase (Lag) in the accumulation of ABTS cation is proportional to antioxidant concentration.

RESULT(S)

Lag showed significantly greater values in the all VAR patients vs non-VAR subjects. Oligospermic-VAR patients showed the greatest values. Lag and sperm motility significantly correlated in VAR normospermic patients. Follicle-stimulating hormone (FSH) showed significant inverse association with Lag in same group.

CONCLUSION(S)

The augmented Lag values could indicate an ineffective utilization of antioxidants in oligospermic-VAR, while in normo-VAR the direct correlation between TAC and motility suggest a potential protective role toward sperm motility. In the same group, the inverse correlation with FSH suggests that greater FSH levels induce a better utilization of antioxidants by spermatozoa.