The Effect of Maternal Obesity on Placental Autophagy in Lean Breed Sows

This study aimed to evaluate the influence of back-fat thickness (BF), at mating of sows, on autophagy in placenta and the potential mechanism. The sows were divided into two groups according to their BF at mating: BFI (15-20 mm, n = 14) and BFII (21-27 mm, n = 14) as the maternal obesity group. The placental samples used for investigating autophagic function and fatty acid profiles were obtained by vaginal delivery. Our results demonstrated that autophagy defects were observed in placenta from BFII sows along with altered circulating and placental fatty acid profiles. Indicative of impaired autophagy, reduced autophagic vesicles as well as LC3-positive puncta were linked to decreased mRNA or protein expression of autophagy-related genes, including ATG5, ATG7, Beclin1, ATG12, LC3, LAMP1 and LAMP2 in the placenta of BFII sows (p < 0.05). Meanwhile, we found reduced conversion of LC3-I to LC3-II and up-regulated protein content of p62 in the placenta from BFII group (p < 0.05). Furthermore, excessive back-fat was also associated with increased activation of AKT/mTOR signaling and decreased mRNA content of transcription factors regulating the autophagic pathway, including PPARα and PGC1α, but increased mRNA expression of NcoR1 in placenta. Together, these findings indicate that maternal obesity incites autophagy injury in pig term placenta, which may contribute to augmented placental lipid accumulation and therefore impaired placental function.