CAREER: Effects of pregnancy and lactation on muscle-tendon form and function in the rat, Rattus norvegicus

This project investigates the structure and function of skeletal muscle and associated connective tissues during pregnancy and lactation. Pregnancy and lactation are two of the most expensive physiological states in mammals. Because individuals cannot increase energy utilization indefinitely to keep up with these metabolic demands, other processes must become less costly.

The research project tests the hypothesis that locomotor costs are reduced during pregnancy and lactation to offset the higher energetic costs. An integrated suite of experimental techniques, including computational modeling, will be used to quantify locomotor activity and form and function of muscles and tendons during movement. This information will lead to a more complete understanding of the metabolic costs of muscle-tendon interactions during locomotion and how they change during pregnancy and lactation, and the results should allow better tailored advice regarding exercise for women in the pre- and post-natal phases.

The project will create 10 paid summer research internships for undergraduates and 10 for high school students, 5-years of a paid lab technician position for an undergraduate student, and three mentored postdoctoral training opportunities at a Primarily Undergraduate Institution. Teaching resources to identify new areas of female-specific anatomy and physiology research will be developed and disseminated.

The project will also test whether teaching female-specific anatomy and physiology in introductory classes increases the sense of belonging for female students in STEM, which could lead to changes in how the subject is taught at the undergraduate level.

The overarching aim of this project is to understand the form and function of skeletal muscle and its connective tissues during pregnancy and lactation. It is hypothesized that hormonal effects on elastic tissues during pregnancy and/or lactation improve locomotor performance by increasing the usage of elastic potential energy. Using a model of mammalian muscle-tendon physiology, the rat Rattus norvegicus, the Principal Investigator will lead a team of undergraduate and postdoctoral researchers to complete the following research and educational aims: [1] Quantify the effects of pregnancy and lactation on gait mechanics, energetics and in vivo muscle-tendon function, using high-speed videography, implanted electromyography, sonomicrometry, and indirect calorimetry. [2] Characterize in situ, during pregnancy and lactation, the form and function of an isolated hindlimb muscle-tendon unit, the lateral gastrocnemius and its contribution to the Achilles tendon.

By using the same subjects to track the function of leg muscle-tendons in vivo and when the muscle-tendon is isolated in an anesthetized animal, muscle-tendon function will be directly linked to whole body movement. [3] Develop teaching resources to identify new areas of female-specific anatomy and physiology research and enhance female STEM students’ sense of belonging. The work will set the stage for a career-long research program that integrates laboratory work on a model organism with comparative field studies, and advances an under-invested field of research with potential impacts on human health and welfare.

The research will be conducted at a Primarily Undergraduate Institution, integrating the project’s educational goals with the scientific work.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.