The effect of commercial conjugated linoleic acid products on experimental periodontitis and diabetes mellitus in Wistar rats

Abstract

Objective: The aim of present study was to determine the effects of conjugated linoleic acid enriched milk on alveolar bone loss, hyperglycaemia, oxidative stress and apoptosis in ligature-induced periodontal disease in diabetic rat model.

Methods: Wistar rats were divided into six experimental groups: 1; non-ligated (NL, n = 6) group, 2; ligature only (LO, n = 6) group, 3; streptozotocin only (STZ, n = 8) group, 4; STZ and ligature (STZ + L, n = 8) group, 5; ligature and conjugated linoleic acid (CLA) (L + CLA, n = 8) group, 6; STZ, ligature and CLA group (STZ + L + CLA, n = 8) group. Diabetes mellitus was induced by 60 mg/kg streptozotocin. Rats were fed with CLA enriched milk for four weeks. Silk ligatures were placed at the gingival margin of lower first molars of mandibular quadrant. The study duration was four weeks after diabetes induction and the animals were sacrificed at the end of this period. Changes in alveolar bone levels were clinically measured and tissues were histopathologically examined. Inducible nitric oxide synthase (iNOS) and Bax protein expressions, serum interleukin-1β (IL-1β), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglyceride levels and tartrate resistant acid phosphatase (TRAP)+ osteoclast numbers were also evaluated.

Results: At the end of four weeks, alveolar bone loss was significantly higher in the STZ + LO group compared to the other groups (p < .05). CLA decreased alveolar bone loss in L + CLA and STZ + L + CLA groups. CLA significantly decreased TRAP + osteoclast numbers and increased osteoblastic activity compared to the STZ + L group (p < .05). Diabetes and CLA increased Bax protein levels (p < .05) however CLA had no effect on iNOS expression (p > .05).

Conclusion: Within the limits of this study, commercial CLA product administration in addition to diet significantly reduced alveolar bone loss, increased osteoblastic activity and decreased osteoclastic activity in the diabetic Wistar rats.

Keywords: Diabetes; TRAP; conjugated linoleic acid; experimental periodontitis; iNOS.