We evaluated the effects of osteopontin (OPN) on bovine sperm capacitation in vitro. Frozen-thawed sperm from a bull previously tested for IVF were separated by Percoll and incubated in TALP medium without capacitating agents (control, N = 494) and in the presence of 10 µg (N = 452) and 20 µg of OPN (N = 482) for 2 h. Following incubation, sperm were exposed for 15 min to 60 ug mL-1 of lysophosphatidylcholine, an agent known to induce the acrosome reaction only in capacitated spermatozoa. Trypan blue was first used to differentiate live from dead spermatozoa; dried smears were then fixed in formalin and stained with Giemsa for acrosome evaluation by light microscopy. The proportion of live, acrosome-reacted spermatozoa, was used to assess the efficiency of capacitation under different incubation conditions. Differences among groups were analyzed by Chi Square. No difference in the percentage of live cells was found between the control and 10 µg OPN (44.8, 48.0 % respectively), whereas sperm viability was significantly (P<0.01) decreased by 20 µg OPN (33 %). Treatment of sperm with both 10 µg and 20 µg of OPN significantly increased the capacitation rate, as indicated by the higher percentages of acrosome-reacted sperm compared to the control (31.3, 33.3 vs 14.4 % respectively; P<0.01). Our results demonstrate that OPN facilitates bovine sperm capacitation in vitro and suggest investigating the effect of this factor on in vitro fertilization. (USDA grant 2004-34437-15106)

Effect of Osteopontin on Bovine Sperm Capacitation.

GASPARRINI, BIANCA;BOCCIA, LUCIA;DE ROSA, ANNA;ATTANASIO, LAURA;DI PALO, ROSSELLA;
2007

Abstract

We evaluated the effects of osteopontin (OPN) on bovine sperm capacitation in vitro. Frozen-thawed sperm from a bull previously tested for IVF were separated by Percoll and incubated in TALP medium without capacitating agents (control, N = 494) and in the presence of 10 µg (N = 452) and 20 µg of OPN (N = 482) for 2 h. Following incubation, sperm were exposed for 15 min to 60 ug mL-1 of lysophosphatidylcholine, an agent known to induce the acrosome reaction only in capacitated spermatozoa. Trypan blue was first used to differentiate live from dead spermatozoa; dried smears were then fixed in formalin and stained with Giemsa for acrosome evaluation by light microscopy. The proportion of live, acrosome-reacted spermatozoa, was used to assess the efficiency of capacitation under different incubation conditions. Differences among groups were analyzed by Chi Square. No difference in the percentage of live cells was found between the control and 10 µg OPN (44.8, 48.0 % respectively), whereas sperm viability was significantly (P<0.01) decreased by 20 µg OPN (33 %). Treatment of sperm with both 10 µg and 20 µg of OPN significantly increased the capacitation rate, as indicated by the higher percentages of acrosome-reacted sperm compared to the control (31.3, 33.3 vs 14.4 % respectively; P<0.01). Our results demonstrate that OPN facilitates bovine sperm capacitation in vitro and suggest investigating the effect of this factor on in vitro fertilization. (USDA grant 2004-34437-15106)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/334802
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