P-011 Maternal gestational methyl donor deficiency affects reproductive development and fertility of mice offspring
Authors: Singh D 
Published: July 2024

Abstract

Study question
Is maternal methyl donor deficiency during gestation affects offspring’s reproductive health at adulthood?

Summary answer
Maternal gestational methyl donor deficiency affects reproductive development and fertility of F1 offspring and also leads to increased post implantation loss

What is known already
Reproductive disorders and their exact mechanisms are scarce in “The developmental origins of health and disease” (DOHaD) hypothesis which well explains the metabolic complications such as obesity, type 2 diabetes and hypertension that may take root during early development. The maternal nutritional environment during early development has important implications on offspring’s health later in life including reproductive health. The gestational period is of critical importance during which major epigenetic reprogramming occurs. The maternal methyl donor deficiency during gestational period may affect this process and epigenetic signatures of developing gametes and the fertility potential

Study design, size, duration
Pregnant female OCT4-GFP mice, fed on control chow diet (CCD) & 40% methyl-donors (Folate, Methionine & Vitamin B12) deficient diet (MDD) from gestation day (GD) 5 to GD 20. The gonadal development of F1 offsprings was studied on gestation day GD 18, post-natal day (PND) 22 and PND 60. Fertility study was done by mating adult F1 male offspring with adult female mice fed on standard diet

Participants/materials, setting, methods
Homocysteine levels in dams (F0) at GD18 were estimated by ELISA. Testosterone levels in F1 offsprings at PND 60 were estimated by ELISA. Furthermore, Serum glucose levels in F1 offsprings were measured at PND 60 and PND 75 by glucometer. Testicular histology, quantitative histomorphometry, immunofluorescence and TUNEL assay was performed at PND 60.

Main results and the role of chance
Fetal weight was reduced at GD13 and GD18 but postnatal body weight at PND 22 and 60 was not significantly affected in MDD group. Teratological defects were observed in pups of 40% MDD group as compared to CDD. Testosterone levels were significantly reduced in F1 offsprings of 40% MDD group. Glucose levels were similar in both the groups at PND 60 but at PND 75 it is significantly higher in case of F1 offsprings of 40% MDD. Maternal serum homocysteine levels and global DNA methylation levels of fetal gonads were affected. Testicular histology was significantly impaired in 40% MDD group at GD18, PND22 and PND60. Quantitative histomorphometry and immunofluorescence study showed the loss of spermatogonia and spermatocytes with significant increase in germ cells sloughing and seminiferous tubules atrophy. Apoptosis is also observed in seminiferous tubules. Copulation index, sperm count and motility was significantly reduced in case of 40% MDD group at adulthood. The F1 offspring of this group were sub-fertile with significant post implantation loss.

Limitations, reasons for caution
Although mice share ∼90% genome with humans, they may not resemble all aspect of physiology or pathology in humans hence it could limit the findings to extrapolate to humans.

Wider implications of the findings
The knowledge gained from this work could be helpful in highlighting the need of gestational micronutrient interventions specially methyl donors, which could help improving maternal and child health as well as reducing the future disease burden of reproductive disorders

Trial registration number
not applicable