Formation of the basal lamina in human embryonal adipose cells--immunohistochemical and ultrastructural evidence.
OBJECTIVE
The aim of the present study was to investigate the formation of the basal lamina in adipose cells during human embryonal development using transmission electronmicroscopy and immunohistochemistry (reactions for collagen type IV and laminin).


METHODS
Material (subcutaneous tissue from the gluteal region) was taken from human embryos aged 6 to 12 weeks of gestation. Part of the material was prepared for immunohistochemical investigation for collagen type IV and laminin by the peroxidase-antiperoxidase (PAP) method with universal PAP mouse kit (Dako Corporation, Santa Barbara, CA, USA) and primary antibodies--monoclonal mouse anti-human collagen type IV in dilution 1:100 and monoclonal mouse anti-human laminin in dilution 1:100 (Dako Corporation, Santa Barbara, CA, USA). Part of the same material was frozen at -18 degreesC and on fresh 5 microm thick cryostat sections Sudan III-hematoxylin staining was performed for lipids' demonstration after Daddi (1986). Another part of the same material was prepared for electron microscopic examination with TEM Philips CM 12.


RESULTS
The results showed that from the 6th week of gestation onward human preadipose cells accumulated lipid droplets in their cytoplasm and expressed positive immunoreactivity for collagen type IV and laminin. First signs of basal lamina could be seen at places outside the plasmalema. Well-developed rough endoplasmatic reticulum was observed which could be associated with the production of collagen and laminin. A time and place related expression was seen in the immunohistochemical and the electronmicroscopical results.


CONCLUSIONS
Formation of the basal lamina of the human adipocytes begins with the onset of adipogenesis and differentiation during the early human embryogenesis (6th week of gestation). The role of collagen type IV and laminin molecules is suggested in this process.
Department of Anatomy, Histology and Embryology, Medical University, Plovdiv.
Pepa K
PK
Atanassova
D017667:Adipocytes / Q000473:pathology* / Q000648:ultrastructure*; D001485:Basement Membrane / Q000196:embryology*; D046508:Culture Techniques; D005314:Embryonic and Fetal Development; D005260:Female; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D011247:Pregnancy; D012494:Sampling Studies; D012680:Sensitivity and Specificity