Abstract:

Objective: To explore the effects and underlying mechanisms of prenatal zinc treatment (zinc sulfate injection)
for pregnant rats exposed to lipopolysaccharide on the behavior and neuroimmune system of their adult female offspring.
Methods: Totally 15 Wistar rats were divided into 3 groups randomly and injected with lipopolysaccharide (LPS) plus zinc
sulfate (LPS + Zn), LPS plus sterile saline (SAL) (LPS + SAL), and SAL plus SAL (SAL + SAL), respectively. Two or
three female offspring during postnatal days 81–86 (n = 10–12 per group) were chosen. The offspring that were in diestrus
or metestrus were placed in a restraint stress tube for 2 hours. In the final 5 min of restraint stress, they were subjected
to different ultrasonic vocalizations. The behavioral duration times and silence duration times were recorded. After the
ultrasonic vocalization test, the rats were removed from the restraint tube and observed in an open field to evaluate motor and
anxiety parameters immediately. Immediately after the open field test, trunk blood was collected in conical tubes, and serum
corticosterone levels and brain derived neurotropic factor were evaluated by enzyme-linked immunosorbent assay (ELISA).
The levels of monoamine and their turnover in the hypothalamus and striatum were determined by high-performance liquid
chromatography (HPLC). Results: Longer silence time (P < 0.05, P < 0.01), longer travel distance (P < 0.05, P < 0.001),
faster average response speed (P < 0.05, P < 0.001), shorter self-grooming time (P < 0.001, P < 0.01), and lower
metabolic rate of norepinephrine in striatum (P < 0.05, P < 0.01) in the LPS + Zn group were observed when compared
with the LPS + SAL and SAL + SAL groups. Lower levels of serum corticosterone (P < 0.05) in the LPS + Zn group
were also found when compared with the LPS + SAL group. Conclusion: Prenatal zinc treatment has a potential
beneficial effect on adult female rat offspring stricken with infectious/inflammatory processes during gestation by
reducing the stress response.

Key words: zinc, gestation, rat, lipopolysaccharide (LPS), offspring, stress response