HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hausman, G. J. Articles by Thomas, G. B. Search for Related Content PubMed PubMed Citation Articles by Hausman, G. J. Articles by Thomas, G. B.

Enzyme Histochemical Studies in an Ontogeny Study of Muscle Development in Ossabaw and Decapitated Fetuses: Cellular Reactions

US Department of Agriculture¹, Athens, GA 30605

Abstract

Fetuses were decapitated in one uterine horn in each of 14 sows at 45 d of gestation. Control (C) and decapitated (D) fetuses were removed by Caesarean section from three sows at 65 d of gestation (total of 10 D and 10 C fetuses), two sows at 85 d (six D and six C fetuses) and nine sows at 110 d (nine C and nine D fetuses) of gestation (Exp. 1). In Exp. 2, four to six fetuses were removed from each of two Ossabaw (O) gilts and three crossbred (C, Landrace x Yorkshire) gilts at 70 d of gestation, from three C and O gilts at 90 d of gestation and from three C and two O gilts at 110 d of gestation. In Exp. 1, one semitendinosis muscle was removed for histochemistry, whereas the contralateral muscle was removed and weighed. A medial portion of biceps femoris muscle was removed and used for histochemistry in Exp. 2. In both experiments, transverse sections (cryostat) of muscle were stained for lipid, glycogen (PAS) and the following enzymes: acid ATPase, NADH-TR, NADPH-TR, malate dehydrogenase (NAD- and NADP-dependent reactions; MDH), succinate dehydrogenase (SDH), -glycerol phosphate dehydrogenase (with and without NAD; -GPDH), isocitrate dehydrogenase (NAD dependent; ICDH), esterase, lipoprotein lipase and lipase. In Exp. 1, body and muscle weights of the two groups were not significantly different (P>.05) at 65 d of gestation, whereas D fetuses were smaller and had lighter weight muscles (P<.05) at 85 d of gestation. Lipid and enzyme histochemistry were similar for C and D fetuses at 65 and 85 d of gestation. At 110 d of gestation, D muscles failed to show normal patterns (C muscle, 110 d) of reactions for the following enzymes: acid ATPase, MDH (NAD), lipid staining, NADH-TR, NADPH-TR and -GPDH. In Exp. 2, there were no histochemical differences between C and D fetuses at all three ages, with the exception of GPDH staining. In both experiments (C and O fetuses), age-associated changes in number of positive fibers were noted for the following reactions and(or) components: lipid, MDH(NAD), NADPH-TR, -GPDH, lipoprotein lipase and lipase. There was a distinction between secondary and primary fibers with GPDH staining in muscles (deep aspects) from 110-d C fetuses (Exp. 1) and 110-d O fetuses. Primary muscle fibers were clearly distinguished from secondary fibers in MDH(NAD)-stained sections from 85- and 90-d C fetuses, 90-d O fetuses and 110-d D fetuses. No such distinction was obvious in sections (MDH, NAD) from 110-d C (Exp. 1 and 2) and 110-d O fetuses. These studies illustrate similar patterns of lipid deposition and similar development of cytoplasmic and mitochondrial enzymes in lean and obese fetal muscle fibers. Fetal decapitation drastically impaired the establishment of normal patterns of lipid deposition and enzyme distribition in muscle fibers after 85 d of gestation.

¹ ARS, Richard B. Russell Agr. Res. Center.