Epigallocatechin‐3‐Gallate (EGCG) Reduces Rotenone Effect on Stallion Sperm–Zona Pellucida Heterologous Binding

Abstract

Stallion spermatozoa are highly dependent on oxidative phosphorylation for ATP production to achieve normal sperm function and to fuel the motility. The aim of this study was to evaluate the response of equine sperm under capacitating conditions to the inhibition of mitochondrial complex I by rotenone and to test whether epigallocatechin-3-gallate (EGCG), a natural polyphenol component of green tea, could counteract this effect. After 2-h incubation of stallion spermatozoa in modified Tyrode's medium, rotenone (100 nm, 500 nm and 5 μm) and EGCG (10, 20 and 60 μm), alone or in combination, did not induce any significant difference on the percentage of viable cells, live sperm with active mitochondria and spermatozoa with intact acrosome. The inhibition of complex I of mitochondrial respiratory chain of stallion sperm with rotenone exerted a negative effect on heterologous ZP binding ability. EGCG at the concentrations of 10 and 20 μm (but not of 60 μm) induced a significant increase in the number of sperm bound to the ZP compared with that for control. Moreover, when stallion sperm were treated with rotenone 100 nm, the presence of EGCG at all the concentrations tested (10, 20 and 60 μm) significantly increased the number of sperm bound to the ZP up to control levels, suggesting that this green tea polyphenol is able to reduce the toxicity of rotenone.

Therapeutic Role of Green Tea Polyphenols in Improving Fertility: A Review

“…The use of EGCG at different concentrations (10, 20, and 60 μM) significantly improved the number of semen bound to the zona pellucida (ZP) up to control levels, suggesting that GrTPs are able to decrease the damage caused by rotenone [ 102 ]. The addition of 25, 50, and 100 μM EGCG to thawed sperm for one hour did not have any effect on sperm viability and acrosome integrity but increased the in vitro penetration rate and the efficiency of fertilization [ 103 ]. GrTPs are expected to have impacts on the treatment and management of idiopathic infertility.…”

Melatonin enhances mitochondrial biogenesis and protects against rotenone‐induced mitochondrial deficiency in early porcine embryos

“…Rotenone also induces Parkinson's disease‐like symptoms in humans and animal models . Moreover, the reproductive system, oocyte maturation, ovulation, and fertilization are affected by exposure to rotenone. However, little is known about the toxic effects of rotenone on porcine early embryo development.…”

Epigallocatechin‐3‐gallate (EGCG) and green tea polyphenols do not improve stallion semen parameters during cooling at 4°C

“…In a recent study (Plaza Davila et al., ), we demonstrated that EGCG helps in protecting stallion sperm function from the negative effect induced by rotenone during in vitro induced capacitation. In that study, we did not find any difference in sperm quality parameters (acrosome reaction and viability) between treatments, but we did observe an important difference in heterologous binding capacity which was decreased by rotenone but fully restored by EGCG.…”

“…Different antioxidants have been tested on chilled stallion spermatozoa to minimize the adverse effects of oxidative stress and to improve sperm quality, but the results obtained are sometimes limited or unsatisfactory. In the present study, we tested different doses of EGCG and green tea extract polyphenols (plant molecules recognized to exert beneficial effects on spermatozoa; Plaza Davila et al., ; Wittayarat et al., , ) on stallion sperm stored at 4°C for 48 hr.…”

“…Green tea extracts contain the polyphenolic compound epigallocatechin‐3‐gallate (EGCG), a powerful antioxidant which removes free radicals by reacting with hydrogen, alkoxy or peroxyl radicals and chelating iron (Plaza Davila et al., ). In addition, EGCG indirectly increases the antioxidant potential by removing free radicals and by stimulating catalase activity (Schroeder et al., ).…”