title: Fetal exposure to a maternal low-protein diet during mid-gestation results in muscle-specific effects on fibre type composition in young rats.
abstract: This study assessed the impact of reduced dietary protein during specific periods of fetal life upon muscle fibre development in young rats. Pregnant rats were fed a control or low-protein (LP) diet at early (days 0-7 gestation, LPEarly), mid (days 8-14, LPMid), late (days 15-22, LPLate) or throughout gestation (days 0-22, LPAll). The muscle fibre number and composition in soleus and gastrocnemius muscles of the offspring were studied at 4 weeks of age. In the soleus muscle, both the total number and density of fast fibres were reduced in LPMid females (P = 0.004 for both, Diet x Sex x Fibre type interactions), while both the total number and density of glycolytic (non-oxidative) fibres were reduced in LPEarly, LPMid and LPLate (but not LPAll) offspring compared with controls (P < 0.001 for both, Diet x Fibre type interaction). In the gastrocnemius muscle, only the density of oxidative fibres was reduced in LPMid compared with control offspring (P = 0.019, Diet x Fibre type interaction), with the density of slow fibres being increased in LPAll males compared with control (P = 0.024, Diet x Sex x Fibre type interaction). There were little or no effects of maternal diet on fibre type diameters in the two muscles. In conclusion, a maternal low-protein diet mainly during mid-pregnancy reduced muscle fibre number and density in 4-week-old rats, but there were muscle-specific differences in the fibre types affected.
authors: Division of Nutritional Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD, UK.
authors: Joanne E
authors: JE
authors: Mallinson
authors: Dean V
authors: DV
authors: Sculley
authors: Jim
authors: J
authors: Craigon
authors: Richard
authors: R
authors: Plant
authors: Simon C
authors: SC
authors: Langley-Evans
authors: John M
authors: JM
authors: Brameld
mesh_terms: D000818:Animals; D002452:Cell Count; D018753:Diet, Protein-Restricted / Q000379:methods*; D005260:Female; D005865:Gestational Age; D006019:Glycolysis / Q000502:physiology; D008297:Male; D024510:Muscle Development / Q000502:physiology*; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology; D018657:Muscle Fibers, Slow-Twitch / Q000502:physiology; D018482:Muscle, Skeletal / Q000166:cytology* / Q000254:growth & development; D009929:Organ Size; D010084:Oxidation-Reduction; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar