FEB 05, 2014 03:00 PM PST

Environmental enrichment in laboratory mice: effects upon reproductive physiology and postnatal development

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  • CONICET Assistant Researcher, Catedra de Fisiologia Humana, Facultad de Ciencias Medicas, INICSA-CONICET, Universidad Nacional de Cordoba, Argentina
      Dr. Marina F. Ponzio's main area of interest is the study of the reproductive physiology of mammals, including gamete and endocrinology research. During the development of her career, she has also developed interest in some aspects of captive animal behaviour and the link with the reproductive function. She obtained a PhD in Biological Sciences in 2006 at the National University of Crdoba, in Argentina where her research was based on the study of the development of fur chewing behaviour in captive chinchillas, an abnormal repetitive behaviour. She is currently an established researcher with the National Science Council of Argentina (CONICET), and she is also a Professor in the Human Physiology Department at the Medicine School at the National University of Crdoba. In this Institution she develops her research and is a member of the Laboratory Animal Care and Use Committee. At present she is studying the effects of environmental enrichment upon reproductive physiology and development of male and female laboratory mice.


    Although a growing body of evidence indicates that environmental enrichment (EE) facilitates normal development and behaviour in laboratory mice, few studies were conducted to demonstrate its impact upon male and female reproductive physiology. Our study investigated the effects of EE on the development and reproductive success of Albino swiss mice, using PVC tubular devices and shredded paper as physical enrichment. Animals were allocated in regular housing cages in groups of five individuals and treated as non-enriched (control, C) or enriched from weaning to adulthood (E). To evaluate the EE effects upon pups development, a third group of females were enriched from the time the male was introduced to achieve pregnancy (EP). In males, evaluated parameters were body, testicular and accessory glands weight, sperm functional activity (motility, viability, acrosome and membrane integrity), testosterone concentration, in vivo fertilization rates, litter size and embryo degeneration percentages. In females, evaluated parameters included body, uterine and ovary weight, spontaneous ovulation, estradiol concentration, in vivo fertilization rates, litter size, pups neurobiological (cliff avoidance, negative geotaxis, surface righting reflex), physical (body weight at d 1, 7, 14 and 21, bilateral pinna detachment, low incisor eruption and eyes opening) and reproductive development (testicular descent, balano-prepucial opening and vaginal opening). No differences were evident in any of the parameters reflecting the basic reproductive physiology of males or females. However, a significantly higher number of pups were born from enriched mothers (C: 9.50.6, n=4; E: 10.70.2, n=5; EP: 12.20.7, n=5; p=0.03). A strong tendency was detected towards a faster development of the physical and reproductive parameters of pups born from both enriched groups, yet significant differences were only observed for testicular descent (day 19, C: 00%, n=16; E: 62.512.5%, n=17; EP: 21.69.7%, n=21; p=0.002). Although EE showed limited effects in this strain of laboratory mice reproductive physiology, a faster pup development appears to be favored by an increased physical complexity in the environment from birth.

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