Tumor necrosis factor-alpha during neonatal brain development affects anxiety- and depression-related behaviors in adult male and female mice.

A nascent literature suggests that neonatal infection is a risk factor for the development of brain, behavior and hypothalamic-pituitary-adrenal axis which can affect anxiety- and depression-related behaviors in later life. It has been documented that neonatal infection raises the concentrations of tumor necrosis factor-alpha (TNF-α) in neonate rodents and such infections may result in neonatal brain injury, at least in part, through pro-inflammatory cytokines. In addition, previous studies have shown that TNF-α is involved in cellular differentiation, neurogenesis and programmed cell death during the development of the central nervous system. We investigated for the first time whether neonatal exposure to TNF-α can affect body weight, stress-induced corticosterone (COR), anxiety- and depression-related behaviors in adult mice. In the present study, neonatal mice were treated to recombinant mouse TNF-α (0.2, 0.4, 0.7 and 1 μg/kg) or saline on postnatal days 3 and 5, then adult male and female mice were exposed to different behavioral tests. The results indicated that neonatal TNF-α treatment reduced body weight in neonatal period in both sexes. In addition, this study presents findings indicating that high doses of TNF- increase stress-induced COR levels, anxiety- and depression-related behaviors in adult males, but increase levels of anxiety without significantly influencing depression in adult female mice [corrected]. Our findings suggest that TNF-α exposure during neonatal period can alter brain and behavior development in a dose and sex-dependent manner in mice.