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Plastic changes induced by neonatal handling in the hypothalamus of female rats
Elisa C Winkelmann-Duarte1, Anelise S Todeschin, Marilda C Fernandes
1Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Sarmento Leite 500, Porto Alegre, RS 90050-170, Brazil.
Insights
Neonatal handling in rats reduced cell numbers in key brain regions like the paraventricular nucleus (PVN) and supraoptic nucleus (SON). These changes persisted into adulthood, indicating lasting effects of early-life experiences on the central nervous system.
Area of Science:
- Neuroscience
- Developmental Biology
- Behavioral Science
Background:
- Early-life experiences significantly influence long-term behavior and physiological functions.
- The hypothalamic paraventricular nucleus (PVN) and supraoptic nucleus (SON) are critical for stress and reproductive regulation.
Purpose of the Study:
- To investigate the impact of neonatal handling on the cellular structure of the PVN and SON in female rats.
- To assess the long-term effects of early-life handling on oxytocin (OT) and glial fibrillary acidic protein (GFAP) expression in these nuclei.
Main Methods:
- Neonatal handling was applied to female rats during the first 10 postnatal days.
- Cellular volume and number in the PVN (parvocellular and magnocellular regions) and SON were analyzed at postnatal days 11 and 90.
- Immunohistochemistry was used to evaluate OT and GFAP expression in adult animals.
Main Results:
- Neonatal handling led to a reduction in cell number in the PVN and SON at both 11 and 90 days of age.
- A decrease in OT-positive parvocellular cells within the PVN was observed in handled adult females.
- No significant differences in GFAP-positive cell optical density were found between handled and non-handled groups.
Conclusions:
- Neonatal handling induces lasting morphological changes in the PVN and SON, suggesting significant neuroplasticity.
- These findings highlight the enduring impact of early-life environment on the developing central nervous system and its functions.
Abstract:
Early-life events can exert profound long-lasting effects on several behaviors such as fear/anxiety, sexual activity, stress responses and reproductive functions. Present study aimed to examine the effects of neonatal handling on the volume and number of cells in the hypothalamic paraventricular nucleus (pPVN, parvocellular and mPVN, magnocellular regions) and the supraoptic nucleus (SON) in female rats at 11 and 90 days of age. Moreover, in the same areas, immunohistochemistry for oxytocin (OT) and glial fibrillary acidic protein (GFAP) were analyzed in the adult animals. Daily handling during the first 10 postnatal days reduced the number of cells in the pPVN and SON at both the 11 and 90 days. Handling decreased the number of OT-positive parvocellular cells in the PVN in adult females. No significant differences were detected on the optical density (OD) of GFAP-positive cells between the handled and nonhandled adult females. The effect of handling on cell loss was observed 24 h after the 10-day handling period and persisted into adulthood, indicating a stable morphological trace. Results suggest that neonatal handling can induce plastic changes in the central nervous system.
