Effects of Dimethyl Sulphoxide and Decitabine on Mouse Salivary Flow Rates

Objectives: To determine the effect of intraperitoneal injections of a saline-DMSO solution on salivary flow rates in adult mice and establish if they mask the increased flow rate caused by Decitabine.
Methods: Twenty four female mice type C57BL/6NCl age 25 weeks were divided into two equal groups. Group 1 mice (control) were injected three times per week for five weeks with a 0.2% solution of DMSO in normal saline. Group 2 mice (experimental) also had 1mg of Decitabine per Kg delivered in the DMSO-saline injection solution. Pilocarpine-stimulated salivary flow rates were measured at weekly intervals. Statistical analysis was by independent t-tests and ANOVA for differences between the groups at end of weeks 2, 3, 4 and 5.
Results: Change from the mean initial flow rate of the control group (mean 34.2 mcL/min , SE 1.64) receiving DMSO-saline was seen at the end of week 2 when a 33.9% fall (mean 22.6 mcL/min, SE 2.08 ) occurred and remained throughout treatment. In Group 2 the same pattern of fall was observed, but was only 7.8% on average (mean 31.6 mcL/min, SE 0.78) across weeks 2, 3, 4 and 5. ANOVA of data from weeks 2, 3, 4 and 5 showed the difference between control and experimental groups was p < 0.001, suggesting the known enhancement of salivary flow rate by Decitabine in 25 week old mice had not been masked by DMSO.
Conclusions: DMSO will reduce salivary flow rate in adult mice if it used as a solubilising agent fo naturally occurring substances. Nevertheless the Decitabine results suggest that effect of DMSO may not mask effects of salivary flow enhancing compounds present.