Epigallocatechin-3-gallate alters the metabolic phenotype of human Sertoli cells but protects from oxidative damage: a possible role for male fertility?

Epigallocatechin-3-gallate (EGCG) is the most abundant catechin in tea (Camellia sinensis (L.) Kuntze, Theaceae). Most of the medicinal properties attributed to tea are suggested to be due to EGCG. Herein, we evaluated the effect of EGCG (5 and 50 µM) on human Sertoli cells (hSCs) metabolism, mitochondrial functionality and oxidative profile.

Exposure to 5 µM EGCG did not cause major alterations on hSCs, but 50 µM of EGCG induced a higher consumption of glucose and pyruvate to sustain the same production of lactate. In fact, hSCs exposed to 50 µM of EGCG presented a decrease in LDH and MCT4 levels, as well as LDH activity, suggesting that the efficiency of lactate production (essential for germ cell development) could be compromised. These metabolic alterations promoted by 50 µM EGCG on hSCs were accompanied by an increased lactate/alanine ratio, which is linked with the NAD⁺/NADH ratio. This alteration on cellular redox status might be associated with mitochondrial dysfunction observed in hSCs of this group. Interestingly, we verified that oxidative damage to proteins and lipids were decreased in hSCs exposed to 50 µM EGCG.

This study suggests that EGCG is a metabolic modulator of hSCs but it appears to be safe to men in reproductive age. Interestingly, our study also illustrates that despite EGCG (50 µM) induces mitochondrial dysfunction in SCs, the oxidative damage is lower than is control cells. Since SCs are responsible for the nutritional support of spermatogenesis and present a Warburg-like metabolism, these findings suggest that EGCG may protect SCs from oxidative damage which may be relevant to male reproductive health.

Acknowledgements: Supported by FCT to PFO (PTDC/QUIBIQ/121446/2010 and Programa Ciência 2008), CICS (PEst-OE/SAU/UI0709/2014), UMIB (PEst-OE/SAU/UI0215/2014) and MGA (SFRH/BPD/80451/2011) co-funded by FEDER via COMPETE/QREN.