Endocrine Abstracts

Objective

The aim of this investigation is to study the redox status of osteoblasts in response to glucose and bacterial lipopolysaccharide (LPS) and their response to minocycline, in a simulated diabetogenic model, using the steroid marker 5 alpha- dihydrotestosterone (DHT)

Method

Monolayer cultures of MG63 osteoblasts were established in Eagle’s MEM incubated for 24 h with radiolabelled testosterone, effective concentrations of LPS20, glucose (G1000), minocycline (M25) micrograms/ml alone and in combinations of LPS+G, LPS+G+M. After a 24 h incubation period the medium was eluted, solvent extracted and evaporated for isolation of formed metabolites. They were then separated in a benzene:acetone solvent system 4:1v/v by thin layer chromatography and the separated metabolites were quantified using a radioisotope scanner.

Results

The main metabolites formed were the diols, DHT and 4-androstenedione. M stimulated production of DHT by 1.3-fold over controls, with an inverse relationship for the weaker metabolite 4-androstenedione. LPS suppressed the synthesis of DHT by 2.4-fold and G reduced yields by nearly 2-fold (n=8;P<0.0001), while LPS in combination with G caused a further 1.4-fold reduction over G alone. When M was added to the combined incubation of LPS+G, DHT yields were elevated by 2.3-fold (n=8;P<0.0001) being similar to control values. There was an inverse relationship in the yield of 4-androstenedione resulting in a 1.5-fold reduction over the yield in response to LPS+G

Conclusion

Bacterial LPS and Glucose caused significant reduction in yields of the steroid biomarker of wound healing DHT. This was overcome by minocycline. Hypoxic states of MG63 osteoblasts induced by bacterial LPS and glucose in an ‘in vitro’ cell culture simulation of the uncontrolled diabetic patient with periodontal disease, demonstrates therapeutic potential for minocycline as a treatment adjunct. This has possible implications on management strategy for periodontal diseases which are associated with chronic inflammation and oxidative stress.