Prenatal LPS increases Inflammation in the Substantia Nigra of Gdnf Heterozygous Mice

Prenatal systemic inflammation has been implicated in neurological diseases, but optimal animal models have not been developed. We investigated whether a partial genetic deletion of glial cell line-derived neurotrophic factor (Gdnf+/-) increased vulnerability of dopamine (DA) neurons to prenatal lipopolysaccharide (LPS). LPS [0.01 mg/kg intraperitoneal (i.p.)] or saline was administered to wild-type (WT) or Gdnf+/- pregnant mice on gestational day 9.5. Male offspring were examined at 3 weeks, 3 and 12 months of age. There was a progressive degeneration of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra (SN) with age in Gdnf+/- but not in WT mice, with no observed effects on locus coeruleus (LC) noradrenergic neurons or DA neurons of the ventral tegmental area. Inflammatory markers were elevated in SN of LPS treated offspring, with exacerbation in Gdnf+/- mice. Intracellular accumulation of alpha-synuclein (alpha-syn) immunoreactivity in DA neurons of SN was observed in all groups of Gdnf+/- and in WT mice with prenatal LPS, with altered distribution between pars reticulata (pr) and pars compacta (pc). The findings suggest that prenatal LPS leads to accelerated neuropathology in the SN with age, and that a partial loss of GDNF exacerbates these effects, providing a novel model for age-related neuropathology of the nigrostriatal DA system.