ABSTRACT
BACKGROUND@#Exposure to the ionizing radiation (IR) encountered outside the magnetic field of the Earth poses a persistent threat to the reproductive functions of astronauts. The potential effects of space IR on the circadian rhythms of male reproductive functions have not been well characterized so far.@*METHODS@#Here, we investigated the circadian effects of IR exposure (3 Gy X-rays) on reproductive functional markers in mouse testicular tissue and epididymis at regular intervals over a 24-h day. For each animal, epididymis was tested for sperm motility, and the testis tissue was used for daily sperm production (DSP), testosterone levels, and activities of testicular enzymes (glucose-6-phosphate dehydrogenase (G6PDH), sorbitol dehydrogenase (SDH), lactic dehydrogenase (LDH), and acid phosphatase (ACP)), and the clock genes mRNA expression such as Clock, Bmal1, Ror-α, Ror-β, or Ror-γ.@*RESULTS@#Mice exposed to IR exhibited a disruption in circadian rhythms of reproductive markers, as indicated by decreased sperm motility, increased daily sperm production (DSP), and reduced activities of testis enzymes such as G6PDH, SDH, LDH, and ACP. Moreover, IR exposure also decreased mRNA expression of five clock genes (Clock, Bmal1, Ror-α, Ror-β, or Ror-γ) in testis, with alteration in the rhythm parameters.@*CONCLUSION@#These findings suggested potential health effects of IR exposure on reproductive functions of male astronauts, in terms of both the daily overall level as well as the circadian rhythmicity.
Subject(s)
Animals , Male , Mice , ARNTL Transcription Factors/genetics , Acid Phosphatase , CLOCK Proteins/genetics , Circadian Rhythm/radiation effects , Epididymis/radiation effects , Gene Expression/radiation effects , Genitalia, Male/radiation effects , Glucosephosphate Dehydrogenase , L-Iditol 2-Dehydrogenase , L-Lactate Dehydrogenase , Mice, Inbred C57BL , Models, Animal , Nuclear Receptor Subfamily 1, Group F, Member 1/genetics , Nuclear Receptor Subfamily 1, Group F, Member 2/genetics , Nuclear Receptor Subfamily 1, Group F, Member 3/genetics , RNA, Messenger/genetics , Radiation Exposure , Radiation, Ionizing , Reproductive Physiological Phenomena/radiation effects , Sperm Motility/radiation effects , Spermatozoa/radiation effects , Testis/radiation effectsABSTRACT
Objective To investigate the breakfast behaviors and nutritional quality among primary and secondary students,and to provide scientific evidence for developing intervention strategies.Method Random three-stage clustering sampling method was employed in the study.A questionnaire survey was conducted among 9194 primary and secondary students aged 6-17y,from seven cities in China.Results The rates of primary and secondary students having breakfast everyday were 97.0%,92.4%,and 93.4%,Most of the students had their breakfast within 30 min after getting up,the rates being 75.4%,74.7%,and 68.6% respectively.Mothers primarily cook breakfast for the students,the rates being 53.1%,49.9%,and 49.7% respectively.In most cases,they had breakfast at home,the rates being 71.8%,67.0%,and 63.8% respectively.The rates of students having poor quality breakfast were above 80%.Conclusion Primary and secondary students are one of the focal target people for preventing unhealthy dietary behaviors due to shortcomings of eating breakfast.It is necessary to improve the nutritional quality of breakfast for better health of students.