Ectopic Lipid Accumulation Correlates with Cellular Stress in Rabbit Blastocysts from Diabetic Mothers

Area of Science:

• Reproductive biology
• Developmental biology
• Metabolic research

Background:

• Maternal diabetes mellitus (DM) in early pregnancy causes reproductive tract hyperlipidemia.
• This creates an altered embryonic environment, potentially impacting early development.
• The specific effects of this hyperlipidemic environment on embryonic metabolism are not fully understood.

Purpose of the Study:

• To investigate the consequences of high environmental lipid levels on embryonic metabolism.
• To analyze gene and protein expression related to lipid metabolism and stress response in preimplantation embryos.
• To compare in vitro and in vivo models of maternal diabetes-induced hyperlipidemia.

Main Methods:

• Rabbit blastocysts were cultured in vitro with a lipid mixture.
• Blastocysts were also obtained in vivo from diabetic, hyperlipidemic rabbits.
• Gene and protein expression of key metabolic and stress markers were analyzed.

Main Results:

• In diabetic rabbits, embryoblast genes involved in lipid import (carnitine palmityl transferase 1) and nuclear receptor signaling (peroxisome proliferator-activated receptors α and γ) were upregulated.
• Trophoblast genes related to fatty acid synthesis and β-oxidation were downregulated.
• Embryoblasts showed increased markers of endoplasmic and oxidative stress (activating transcription factor 4, nuclear factor erythroid 2-related factor 2), while trophoblasts showed increased markers of cellular redox status and stress (superoxide dismutase 2, heat shock protein 70).

Conclusions:

• The observed gene and protein expression patterns suggest an adaptive response to the hyperlipidemic environment.
• Maternal lipids significantly impact intracellular metabolism in preimplantation embryos during diabetic pregnancy.
• Embryoblasts appear particularly vulnerable to the metabolic stress induced by maternal diabetes.