Evidencies of rat tail tendon proteoglycans at field scanning electron microscopy

Alcian blue (AB) in critical electrolyte concentration (CEC) was used for scanning electron microscopy (SEM) on rat tail tendon. Segments with diameters of 4 to 9 nm are evident in the perifibrillar area with their lengths ranging from 180 to 400 nm. Frequently the segments adhere closely to collagen gap zones. Segments are not evident either in specimens fixed in glutaraldehyde or in specimens stained with AB in CEC solutions previously treated with glycanolytic enzymes. The segments suggestively correspond to electrodense filaments evident in transmission electron microscopy (TEM) if the rat tail tendon is similarly treated (Scott, 1981). It may be concluded that AB in CEC solutions can be utilized for SEM investigations and represents a good method for the detection of the three dimensional disposition of proteoglycans (PG) and their interaction with collagen.