Cytochemical study of in situ differentiation of white adipose cells in rat.
OBJECTIVE
The aim of the present study was to follow up the histochemical and enzyme-histochemical characteristics of differentiating white adipose cells of rat in situ.


METHODS
Nine rat fetuses aged 15-21 day of gestation were used. Fragments from the subcutaneous tissue of lower limb were frozen at -18 degrees C. On consecutive cryostat sections Sudan III-hematoxylin staining and enzyme-histochemical reactions for NADH2-cytochrome C-reductase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase and lipoprotein lipase were performed.


RESULTS
The onset of the rat adipocyte differentiation was detected at days 15-16 of gestation. It was seen as appearance and accumulation of lipid droplets, rounding of the cells and displacement of the nuclei to the cell periphery. Gradually, with the advance of gestational age the number of differentiating adipose cells increased and lipid packages, composed of mature-like unilocular adipocytes and multilocular adipocytes that had not yet completed their differentiation, were formed. The differentiating embryonal adipose cells expressed positive enzyme-histochemical reactions for NADH2-cytochrome C-reductase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase and lipoprotein lipase.


CONCLUSIONS
The described histochemical and enzyme-histochemical characteristics could be used as markers for distinguishing the earliest embryonal adipose cells in rat, which is impossible with the classic histological techniques. At the same time they might be accepted as the primary morphological criteria of adipocyte differentiation in situ.
Atanassova
Pepa K
PK
Department of Anatomy, Histology and Embryology, Medical University, Plovdiv, Bulgaria.
D017667:Adipocytes / Q000166:cytology / Q000201:enzymology*; D000273:Adipose Tissue / Q000166:cytology / Q000196:embryology* / Q000201:enzymology; D000818:Animals; D002454:Cell Differentiation; D005314:Embryonic and Fetal Development; D004798:Enzymes / Q000378:metabolism; D005333:Fetus / Q000196:embryology* / Q000201:enzymology; D007150:Immunohistochemistry; D050356:Lipid Metabolism; D008297:Male; D051381:Rats; D040521:Subcutaneous Tissue / Q000196:embryology / Q000201:enzymology
D004798:Enzymes