Science and Technology Production
Libro de Resúmenes XLII Reunión Científica Anual de la Sociedad de Biología de Cuyo - INTERSPECIES VARIABILITY IN THE RESPONSE OF MAMMARY TISSUE OF PRECOCIAL AND ALTRICIAL RODENTS CULTIVATED UNDER THERMAL STRESS CONDITIONS
Congress
Date:
2024Publishing House and Editing Place:
Sociedad de Biologia de CuyoSummary *
The increase in environmental temperatures associated with climate change has detrimental effects on the growth and welfare of animal species. Among the deleterious consequences, thermal stress disrupts the development of the mammary gland (MG), thereby affecting the nutritional provision to the offspring. In this study, we assessed the repercussions of thermal stress on the MG of two distinct rodent species that exhibit divergent nutritional requirements for their neonates: the wild plains vizcacha (Lagostomus maximus), a precocial model, and the laboratory mouse (Mus musculus), an altricial model. For this purpose, MG explants were incubated at 42°C (simulating a hyperthermic condition) and tissue samples collected at time points of 0 (CT) and 4 h (heat stress, HS). Morphological and morphometric analysis were performed over hematoxylin-eosin stained MG sections using the Aperio ImageScope Software. After 4-hour exposure to hyperthermic conditions, vizcacha MG explants showed a statistically significant reduction in the parenchyma/stroma ratio (p<0.05, Student's t-test). Such changes are attributable to a reduction in the alveolar compartment primarily resulting from HS-induced constriction of secretory acini. Conversely, murine MG explants exhibited an increase in the parenchyma/stroma ratio after 4 hours at 42ºC (p<0.05), which was due to an expansion of the alveolar surface area. Additionally, murine secretory acini lumen was also enlarged after 4 hours of culture at 42 °C, which contributed to the observed increase in alveolar area. A preliminary morphometric evaluation indicated a rise in adipocyte density in mouse HS explants, leading to a subsequent hypothesis regarding a potential protective role of these cells against thermal stress. The interspecies variability in the parenchyma/stroma ratio post-exposure to HS suggests an evolutionary adaptation of the endocrine systems of altricial species to extreme thermal fluctuations, with a MG capable of preserving its integrity and ensuring sufficient nutritional support to neonatesthat are highly dependent on maternal care for survival. UMAI intramural & PIP/CONICET GI 11220200100036CO fundings Information provided by the agent in SIGEVAKey Words
pregnancymammary glandRodentiaheat stress