Immunosuppressant therapy and bone loss in ligature-induced periodontitis--a study in rats.

Immunosuppressive agents have been recognized as a factor affecting the soft tissues of the periodontium. However, little is known about their effect on periodontitis progression. The aim of the present study was to investigate the influence of cyclosporin A (CsA) administration, associated or not with nifedipine, on the bone loss resulting from a ligature-induced periodontitis in rats. Twenty-four adult male Wistar rats were used. After anesthesia, the mandibular first molar was randomly assigned to receive the cotton ligature in the sulcular area while the contralateral tooth was left unligated. The animals were randomly assigned to one of the following treatments: Group A--saline solution; Group B--CsA (10 mg/kg); Group C--nifedipine (50 mg/kg); Group D--CsA (10 mg/kg) plus nifedipine (50 mg/kg). Forty-five days later, the animals were sacrificed and the specimens routinely processed for serial decalcified sections. Intergroup analysis did not reveal significant differences regarding the bone loss volume in the ligated teeth between the experimental treatments (0.46 +/- 0.11, 0.63 +/- 0.32, 0.53 +/- 0.14, 0.50 +/- 0.18, for groups A, B, C and D, respectively--p > 0.05). However, intragroup analysis showed a greater bone loss volume in the ligated teeth than in the unligated ones (p < 0.05). Within the limits of the present study, the conclusion was that the administration of CsA, associated or not with nifedipine, may not influence bone loss in ligature-induced periodontitis in rats.