Effects of nasal ZnSO4 irrigation and olfactory bulbectomy on rat pups

Rat pups underwent bilateral olfactory bulbectomy (BOB) or irrigation of the nasal cavities with a 5% ZnSO₄ solution (Zn) at 2, 7, 11, or 13 days of age to determine whether the effects of these treatments are similar. Control pups were sham operated, handled only, or had their nasal cavities irrigated with saline. Both Zn and BOB pups lost weight, sometimes to the point of death, and exhibited deficiencies in attachment and suckling behavior compared to control animals. Histological investigation indicated degeneration in the olfactory epithelium and shrinkage of the glomerular layer of the olfactory bulb as a result of the nasal ZnSO₄ treatment. The vomeronasal organs of the Zn animals appeared to be intact. As a control for possible toxic effects of nasal ZnSO₄ irrigation, 12-day-old pups had their oral cavities irrigated with a 5% ZnSO₄ solution. Their weight gain and attachment and suckling behavior was like that of control pups.