Pyrroloquinoline quinone promotes porcine oocyte in vitro maturation and subsequent embryo development by enhancing lipid metabolism and improving mitochondrial function.

Objective: The present study evaluated the beneficial effects of pyrroloquinoline quinone (PQQ) on in vitro maturation (IVM) of porcine oocyte and subsequent early embryo development.

Methods: Porcine cumulus oocyte complexes were cultured in IVM medium with supplementation of 0, 200, 400, 800 or 1600 nM PQQ for 42 h. We first examined cumulus expansion index (CEI) and the rate of oocyte nuclear maturation. Then, we assessed oocyte mitochondrial function, oxidative stress levels, lipid metabolism and subsequent embryonic development.

Results: PQQ (800 nM) supplementation significantly increased CEI and the nuclear maturation rate of oocytes following IVM. Additionally, oocysts supplemented with 800 nM of PQQ showed significantly increased mitochondrial content, mitochondrial membrane potential, activity, and mRNA expression levels of genes associated with mitochondrial biogenesis (PGC-1a, NRF1, NRF2 and TFAM). PQQ significantly reduced the levels of reactive oxygen species, lipid drop-lets, and fatty acids content, while enhancing the mRNA expression levels of genes related to antioxidant activity (SOD1, SOD2, GPX and CAT), lipolysis (ATGL and HSL) and β-oxidation (CPT1B and CPT2) in porcine oocytes. PQQ (800 nM) supplementation significantly increased cleavage rate, blastocyst formation rate, and total blastocyst cell numbers following partheno-genetic activation.

Conclusion: PQQ supplementation during IVM positively influences porcine oocyte maturation and subse-quent embryonic development by enhancing mitochondrial function and lipid metabolism and alleviating oxidative stress.