Abstract
Objective: The presented work was conducted to test the effectiveness of activated charcoal on the lingual mucosa of male rats subjected to the immunosuppressive drug tacrolimus.

Design: After random allocation of thirty healthy male Wistar albino rats into three groups (10 per group), in the control group animals received saline, whereas those in the tacrolimus (TAC) group received daily subcutaneous injections of the immunosuppressant. In the third cohort (tacrolimus and activated charcoal; TAC+AC), rats received activated charcoal orally administrated besides the TAC. After three weeks of treatment, the evaluation of dissected tongues exempted histological, immunohistochemical, and morphometrical analyses.

Results: Histological findings revealed mucosal and connective tissue degenerative changes induced by TAC. However, the AC group showed the preserved structure of the lingual mucosa and associated minor salivary glands. The immunohistochemical detection of Melan-A revealed the profound drop in the mean area percent and optical density of melanophages to 0.82 ± 0.2% and 0.12 ± 0.01, respectively, upon AC counteraction of TAC melanosis.

Conclusions: AC exerted protective action against the degenerative effect of TAC on the lingual mucosa, encouraging its adjuvant uptake throughout the immunosuppressants course.