Effect of alendronate on bone-specific alkaline phosphatase on periodontal bone loss in rats.

Objective: The study aims to evaluate the effect of alendronate (ALD) on bone-specific alkaline phosphatase (BALP) serum levels on periodontal bone loss in Wistar rats.

Design: Periodontitis was induced by ligature around the upper second molar in 36 male Wistar rats (± 200 g). Groups of six animals received 0.9% saline (SAL) or ALD (0.01; 0.05; 0.25 mgkg(-1), s.c.), over 11 days; then they were sacrificed and their maxillae were removed to be defleshed and stained for macroscopic or histopathological analysis. Blood samples were collected for BALP, transaminases and total alkaline phosphatase (TALP) serum dosage, and haematologic study. Rats were weighed daily.

Results: Periodontitis induction caused reduction of BALP, intense alveolar bone loss (ABL), cementum and periodontal ligament destructions and intense leucocyte infiltration seen microscopically. Systemically, periodontitis induced leucocytosis, weight loss and TALP reduction. ALD (0.25 mgkg(-1)) prevented BALP reduction (19.17 ± 1.36 Ul(-1)) when compared to SAL (13.6 ± 1.5), as well as prevented ABL, by 57.2%, when compared to SAL (4.80+0.18 mm(2)), which was corroborated by histological findings (ALD 0.25 mgkg(-1)=1.5 (1-2) and SAL=3 (2-3)) (p<0.05). ALD did not alter transaminases but reduced TALP levels (p<0.05). ALD 0.25 mgkg(-1) reduced 6th-h neutrophilia (2.50 ± 0.22cell × 10(3)mm(-3)) and 7th- (12.29 ± 0.66) and 11th-day lymphomonocytosis (15.74 ± 0.52) when compared to SAL (5.20 ± 0.28; 18.24 ± 1.05; and 23.21 ± 1.48, respectively). ALD did not alter the weight loss.

Conclusion: ALD prevented BALP reduction and ABL and reduced inflammatory infiltrate, without causing systemic alterations.