Objective: 

Neonatal injection of bacterial cell wall constituents or lipopolisaccarides (LPS) appears to program reproduction in adulthood. These effects might be mediated by increasing levels of IL-1beta and NO. We, therefore, hypothesized that neonatal LPS injection may affect puberty and prevention of rise in IL-1beta and NOS following LPS injection may prevent this delay in male rats.

Methods: 

Male pups were injected with LPS (n=11; 50 ug/kg LPS), LPS + IL-1beta inhibitor (n=16, 1 mg/kg Q-Vd-OPh), LPS + NOS inhibitor (n=13, 40 mg/kg L-NAME) or saline (n=14) on postnatal day 7. All pups were kept under 12h light: 12 h dark cycle. However, in order to increase signal intensity in terms timing of puberty, all pups were kept at 16 h light: 8 h dark cycle between postnatal days 18 and 42. From postnatal day 40 onward, rats were observed daily for preputial separation.

Results: 

Neonatal LPS injection and inhibition of IL-1beta and NOS did not affect days to preputial opening.

Conclusions: 

The results obtained so far suggest that neonatal LPS injection was not sufficient to produce a sufficient signal to affect days to preputial opening.