Differential microglial and astrocytic response to bacterial and viral infection in the developing hippocampus of neonatal rats.

ABSTRACT

Polyinosinicpolycytidylic acid (Poly IC; 5 mg/kg body weight, ip) and lipopolysaccharide (LPS; 0.3 mg/kg body weight, ip) induced microglial and astrocytic activation in Sprague Dawley rats. Higher microglial and astrocytic activities were noticed in Poly IC infused rats throughout the hippocampus till postnatal day 21 with a comparatively weaker response in LPS group. However, LPS induced inflammation persisted even after postnatal day 21, indicating thereby, that the Poly IC (viral mimic) produces an acute inflammation, while LPS (bacterial endotoxin) produces chronic inflammation when exposed during early neonatal life.