Exploring the effects of embryonic and neonatal exposure to lipopolysaccharides on oligodendrocyte differentiation in the rat hippocampus and the protective effect of alpha-glycosyl isoquercitrin

This study compared the effects of embryonic and neonatal lipopolysaccharides (LPS) exposure (E-LPS and N-LPS) on oligodendrocyte (OL) differentiation in the hippocampus of male rats and explored the protective effect of the antioxidant alpha-glycosyl isoquercitrin (AGIQ). Using SD rats, LPS exposure occurred either intraperitoneally in dams between gestational days 15 and 16 (50 µg/kg body weight/time) or in male pups on postnatal day (PND) 3 (1 mg/kg body weight). Under both regimens, AGIQ at 0.5% (w/w) was supplemented, to dams from the gestation period (before LPS exposure) until weaning on PND 21 and to male offspring from weaning until PND 77 (adulthood). Compared with a control treatment, E-LPS treatment resulted in fewer NG2⁺ OL progenitor cells (OPCs) and an upregulation of Tcf4 at PND 6; by PND 21, low NG2⁺ OPC number persisted, but OLIG2⁺ OL lineage cells increased, while CNPase⁺ mature OLs counts were unchanged. By contrast, N-LPS treatment resulted in fewer OLIG2⁺ cells and an upregulation of Bmp4 at PND 6; by PND 21, NG2⁺ OPCs decreased, while GFAP⁺ astrocytes increased at both PND 6 and 21. After N-LPS treatment, Kl and Yy1 were downregulated and there were fewer Klotho⁺ and CNPase⁺ cells at PND 21. Results suggest that E-LPS treatment facilitates OPC differentiation into pre- and immature OLs until weaning, while N-LPS treatment suppresses OPC differentiation into mature OLs but facilitates astrocyte generation; however, these changes spontaneously recovered by adulthood under both regimens. AGIQ treatment ameliorated the effects of LPS treatment of both regimens, suggesting that LPS-induced disruption of OPC/OL differentiation occurs via neuroinflammation.