Pentoxifylline induces hyperactivation and acrosome reaction in spermatozoa of golden hamsters: changes in motility kinematics

Abstract

Pentoxifylline (PF) is used to enhance motility of spermatozoa from infertile human subjects. We have previously shown that 0.45 mM PF improved capacitation of spermatozoa and fertilization of oocytes in vitro in hamsters. The present study was carried out to assess PF-induced changes in motility kinematics of hamster spermatozoa by a computer-aided sperm analyser (CASA) and determine the timing of onset of hyperactivation (HA) and acrosome reaction (AR) in PF-treated spermatozoa. Motility kinematics were analysed by CASA for 0-8 h in the absence or presence of 0.45 mM PF in Tyrode's medium supplemented with lactate, pyruvate and polyvinyl alcohol (TLP-PVA) or in TLP-PVA with bovine serum albumin (TALP-PVA). Conventional assessment was also made on the percentage of motility and quality of motility of spermatozoa; values were expressed as sperm motility index (SMI). Both in TALP-PVA and TLP-PVA, PF markedly increased SMI, especially the quality of motility (P < 0.02) by 2-3 h which was sustained up to 6 h. The motility kinematic data of PF-treated spermatozoa in TALP-PVA showed that average path velocity, curvilinear velocity and amplitude of lateral head displacement significantly (P < 0.05) increased as early as 2 h, with the expected decrease in straightness (STR) and linearity (LIN). Similar changes were also observed with PF-treated spermatozoa in TLP-PVA. Moreover, the percentage of hyperactivated spermatozoa in PF-treated samples was significantly (P < 0.001) higher than the untreated control at 2 h. To determine whether PF could induce AR, independent of bovine serum albumin, quantitative AR was assessed by observing the presence or absence of acrosomal cap on viable spermatozoa. PF significantly (P < 0.001) increased the percentage of AR as early as 2 h, reaching maximum at 4 h both in TALP-PVA (P < 0.05) and in TLP-PVA (P < 0.001). These results show that, in hamsters, PF induces early onset (by 2 h) of HA and AR and increases the proportion of spermatozoa undergoing physiological maturation.

Pentoxifylline-stimulated capacitation and acrosome reaction in hamster spermatozoa: involvement of intracellular signalling molecules

“…Briefly, 2 µl of neat cauda epididymal content were incubated in 2 ml of pre-equilibrated TALP-PVA (Tyrode's solution supplemented with 3 mg/ml bovine serum albumin), 10 mM sodium lactate, 0.25 mM sodium pyruvate and 1 mg/ml polyvinyl alcohol) and incubated in a humidified atmosphere of 5% CO 2 in air at 37°C. The following reagents were included in the culture medium as indicated in the results: pentoxifylline [9-(5-oxohexyl)-3,7-dimethylxanthine], 0.45 mM (Rupasri et al, 1995;Jayaprakash et al, 1997); 4,4-diisothiocyanatostilbene-2,2 disulphonic acid (DIDS), 1 mM (Visconti et al, 1990); N- [2-(p-bromocinnamylamino)ethyl]5-isoquinolinesulphonamide (H89);10 µM (Leclerc et al, 1996); STP 1 nM (Lax et al, 1994); tyrphostin A-47, 0.1 mM (Leyton et al, 1992); aristolochic acid, 0.4 mM (Garde and Roldan, 1996); and progesterone, 0.1 mM (Kay et al, 1994). All test compounds were added from the start of the culture period.…”

“…An SMI value ജ1200 indicated that the spermatozoa were capacitated. Sperm motility was determined using a standard procedure (Bavister and Andrews, 1988;Rupasri et al, 1995;Jayaprakash et al, 1997).…”

“…Sperm kinematic analysis was carried out using computer-aided sperm analysis (CASA) (HTM-S Motility Analyzer, version 7.2; Hamilton Thorn Research, Danvers, MA, USA), as detailed elsewhere (Jayaprakash et al, 1997). Briefly, a 20 µl aliquot of each sperm incubation was transferred to a slide chamber (80 µm depth) for analysis.…”

“…pentoxifylline or progesterone, are used in assisted reproductive technology (ART) to enhance the fertilizing potential of inherently poor quality spermatozoa from oligoasthenozoospermic patients (Yovich et al, 1990;Kay et al, 1994;Matson et al, 1995;Tournaye et al, 1995;Baldi et al, 1998). We have shown that 0.45 mM pentoxifylline can stimulate capacitation and AR in hamster spermatozoa (Rupasri et al, 1995;Jayaprakash et al, 1997). Whether this is mediated via changes in the concentrations of cAMP/cGMP, [Ca 2ϩ ] i and the activity of protein kinases is unknown.…”

Effects of Fertilization Promoting Peptide, Adenosine, and Pentoxifylline on Thawed Human Sperm

“…Pentoxifylline, clinically used to enhance motility of sperm from infertile men, is a phosphodiesterase inhibitor leading to an increase in intracellular cAMP level [17]. In hamsters, pentoxifylline induces capacitation, hyperactivation, and acrosome reaction, and improves fertilization rates in vitro [16,18]. The application of pentoxifylline contributes to enhancement of thawed sperm motility [4] and selection of viable sperm in intracytoplasmic sperm injection [10].…”