Changes in lectin binding to bovine sperm during heparin-induced capacitation

Abstract

Changes in the plasma membrane of bovine sperm during heparin‐induced capacitation were detected by the binding of fluorescent labeled lectins to unfixed sperm. Of the seven lectins evaluated, only binding of wheat germ agglutinin (WGA) changed with capacitation. Sperm were classified into one of 5 patterns (p1–p5) based on staining with WGA, presence or absence of propidium iodide (PI) staining (dead or alive), and acrosomal integrity (acrosome intact or reacted). The major changes associated with capacitation occurred in p1 and p2. Sperm in p1 exhibited diffuse WGA binding over the anterior sperm head, were alive, and had intact acrosomes. In p2, sperm were also acrosome intact and alive, but lacked WGA binding. When sperm were incubated under capacitating conditions with heparin, there was a decrease over time in the percentage of sperm classified in p1 (p < 0.05) and an increase in the percentage of sperm in p2 (p < 0.05). When capacitation by heparin was delayed by the inclusion of glucose in the culture medium, the same heparin‐dependent changes in the percentage of sperm in p1 and p2 were delayed (p < 0.05). When capacitation by heparin was inhibited by including protamine in the culture medium, the percentage of sperm in p1 or p2 was not different from sperm incubated without heparin. Heparin‐induced capacitation was associated with a loss of WGA binding to the bovine sperm head. © 1996 Wiley‐Liss, Inc.

Heterologous In Vitro Fertilization and Sperm Capacitation in an Endangered African Antelope, the Scimitar-Horned Oryx (Oryx dammah)1

“…Rather, Ca 2+ may have increased the sensitivity of the functional assay used for detecting capacitation by enhancing the ability of cells to acrosome-react. Recently, an alteration in lectin-binding patterns has been associated with heparin-induced sperm capacitation and offers a promising method for evaluating capacitation independent of the acrosome reaction [43]. Regardless of actual mechanism, additional CaCl improved conditions for capacitating and inducing the acrosome reaction in oryx sperm.…”

Bovine in vitro fertilization: In vitro oocyte maturation and sperm capacitation with heparin

“…The BSPs interact with both cholesterol and phospholipids in the sperm plasma membrane. Following heparin binding, there is a loss of lectin binding to bovine sperm indicating the loss of sperm surface components [31,32]. The changes in surface components likely relate to a heparin induced loss of the BSPs over time that lead to a loss of membrane cholesterol and phospholipid [30].…”

Intracellular pH of bovine sperm increases during capacitation

“…Capacitation of bovine sperm by heparin involves heparin binding to sperm, plasma membrane changes that can be detected by lectin binding, increases in sperm calcium uptake, increases in intracellular calcium (CaJ, and an increase in sperm CAMP (Parrish et al, 1988a(Parrish et al, ,b, 1993Medeiros and Parrish, 1991;Mahmoud and Parrish, 1992;Handrow et al, 1989;Uguz et al, 1994). In previous studies it was also reported that capacitation of bovine sperm was accompanied by an increase in pHi of 0.36 pH units that appears to be necessary for capacitation (Parrish et al, 1989b).…”