UNIT 6.2
Reproduction and Development
in Hypo- and Hypergravity
Presented by:
Dr. April Ronca
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RODENTS
UNIT 6.2
Reproduction and Development in Hypo- and
Hypergravity
Dr. April Ronca
Vocabulary:
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Cutaneous
Fertilization
Hypergravity
Hypogravity
Mammals
Placentation
Prenatal
Postnatal
Vestibular
Purpose:
To help engineers better understand the effects of altered gravity on the reproductive and
development processes.
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RODENTS
Why Study Reproduction and Development in Altered Gravity?
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Advance the understanding of gravity dependence /independence of biological
development.
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Developing systems can provide a ‘simplified’ view of adult systems.
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Establish feasibility of long-term animal and human habitation of space.
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Determine whether major steps of reproduction can proceed in space.
What Do We Know About Reproduction and Development in Space?
Medaka
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The first vertebrate mating in space
The first hatching of eggs in space
Rattus norvegicus
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The first pregnant mammals in space
The first mammals to develop in space
Medaka
(A small freshwater fish)
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Adult size
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Conditions for Mating and Egg-Laying
o Lighting:
14 hours light - 10 hours dark
o Temperature: 23-28° C
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Mating Habits Fish mate and lay eggs daily within 2 hours of lights on
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Eggs and Embryos
o Egg Size:
1.0mm diameter
o No. of Eggs: 5-25 eggs per female per day
o Hatching:
10 days after fertilization
0.7 gm weight - 3 cm length
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Medaka were flown on STS-65 in 1994 as part of the International
Microgravity Laboratory (IML-2) Mission
Investigator: Kenichi Ijiri, University of Tokyo
Four fish were flown
(two males and two female)
Results of the Medaka Experiment
Eggs were laid and developed
normally with two pigmented
eyes
Mating was successful
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Results of the Medaka Experiment
Hatching was Successful:
A truly space-originated life
Close up of
the baby
fish in
space
Baby fish swimming
with mother in space
Results of the Medaka Experiment
Re-Adaptation to Earth’s 1-g: It’s Not As Easy As You Think!
Adult fish were immobile
Each time the fish attempted to
swim up, they dropped back to
the floor of the tank
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Can Mammals Reproduce and Develop in Space?
Complete Life Cycle in Space
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Mating
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Fertilization
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Establishment of placenta
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Pregnancy
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Prenatal development
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Birth
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Postnatal Development
Space Traveler?
The ‘Cat in the Hat’ study reveals the
remarkable ability of the infant’s
brain to learn even before birth.
Newborns come into the world with
the ability to see, hear, taste, smell and
touch. These abilities develop during
the last few months of pregnancy.
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Maternal Movement During Pregnancy:
Effects on Prenatal Sensory Development
Mammalian Development in Space *
* See Supplement Section – Page 250.
Pregnant spaceflight rats had two times more labor contractions as
compared to pregnant earth rats.
Contractions (% change from control)
80
60
NIH.R
NIH.R1
40
20
0
Control
-20
HG Study
-40
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The ‘Stress’ of Being Born
Adults During Rest
Men During Sauna Bath
Women During Delivery
Men During Exercise
Patient with Pheochromocytoma
Infants at Birth
0
20
40
CATECHOLAMINES (NM / L)
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Mother as a Vehicle for Developing Young
Flight Offspring Show a Precocious Pattern of Response to Tilt Stimulation
Change from baseline (BPM)
20
Flt
Syn
Viv
15
10
5
0
-5
-10
-15
-20
-30
-15
0
15
Time
203
30
45
60
RODENTS
‘Righting‘ on a Surface was Unaffected by Prenatal Development in Space
Water ‘Righting’ was Temporarily Impaired Following Prenatal
Development in Space
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What About Motor
Development?
Stages
of
Motor
Development
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Notes:
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