1991 Volume 33 Issue 6 Pages 546-559
To investigate differences between the cementocytes and osteocytes located in the lacunar and canalicular spaces of tissue fluid transport pathways, we intravenously injected either microperoxidase (MP) or horseradish peroxidase (HRP) into the jugular veins of 6-to-7-week-old Sprague-Dawley rats.
In the cellular cementum, HRP was detected throughout all lacunae and canaliculi containing cementocytes, and MP was found in most of these lacunae and canaliculi. MP and HRP were also detected within the organelles (micropinocytotic vesicles, phagosomes, multivesicular bodies and denseb odies) of nearly all cementocytes. However, the uptake of MP was more prominent in young cementocytes than in mature cementocytes, while there was no significant difference between young and mature cementocytes in HRP uptake.
In the alveolar bone, MP and HRP infiltrated all lacunae and canaliculi containing osteocytes and were also detected within the same organelles in osteocytes as those in cemento cytes. HRP was particularly deposited along the innermcst edge of the mineralized bone matrix and was extensi vely taken up by osteocytes.
These results suggest that the main transport pathways for tissue fluids within cementu m and bone are located in the external areas of the pericellular spaces, and that cementocytes are engaged in metabolic activities similar to those of osteocytes.
