Changes of the basal lamina in the rat gingiva receiving incisional wound and bacterial protease application

The purpose of the present ultrastructural study was first to investigate the changes of the basal lamina in the gingiva which were produced by both wounding and bacterial prot ease application and second to investigate the fate of the changed basal lamina with time. In all 4 groups, animals received an incision in the lingual gingiva. Immediately after incision, wounds of Groups A and C were treated with distilled water, and those of Groups B and D with bacterial protease. Histologically, in Groups A and B on Day 4, the gingival connective tissues showed granulation. In the former group the basement membrane appeared relatively clear, whereas in the latter it was in-di stinct. In both groups on Day 28, the gingiva appeared normal. Ultrastructurally, in Group Con Day 4, the basal lamina exhibited various changes such as detachment, breaking, thickening, fragmentation and multiplication, but on Day 28, these changes had improved. In Group D on Day 4, the above-mentioned changes were more conspicuous than those of Group Con Day 4, and in the connective tissue, fibroblast-like cells were sometimes in contact with the basal cell. On Day 28, the changes of the basal lamina had improved, but they were more marked than those of Group C on Day 28. In conclusion, the present results suggested that the rat gingiva receiving wo unds and bacterial protease showed conspicuous changes of the basal lamina and that these changes were reduced in intensity with the passage of time.