HISTOCHEMICAL ANALYSIS OF ACIDIC GLYCOCONJUGATES IN THE ENDOTHELIUM LINING THE SPLENIC BLOOD-VESSELS IN THE RAT

An electron microscopic analysis with specific histochemical stainings for acidic glycoconjugates was carried out to examine the endothelium lining blood vessels of the rat spleen, Histochemical staining perfor med was the postembedding high or low iron diamine-thiocarbohydrazide- silver protein-physical development (HID or LID-TCH-SP-PD) method, wit h or without prior digestion with acidic glycoconjugate-degrading enzy mes, such as heparitinase, testicular hyaluronidase, chondroitinase B and neuraminidase. The results indicated that the acidic glycoconjugat es in the basal lamina of the endothelial cells lining the four types of blood vessel(central arteries, arterial capillaries, splenic sinuse s and pulp veins) were heparan sulfate, chondroitin sulfate A, and/or C, chondroitin sulfate B and sialic acid residues. In the endothelial cells lining the central arteries, arterial capillaries and pulp veins , the surface coat of the luminal plasma membrane included heparan sul fate, chondroitin sulfate A and/or C, chondroitin sulfate B and sialic acid residues, whereas the corresponding ultrastructure of the spleni c sinuses was devoid of detectable amounts of acidic glycoconjugates. This suggests that such characteristic histochemical features of the e ndothelium in the four types of the splenic blood vessel can be relate d to the possible physiological functions of the spleen.