Effects on mouse immunity of long-term exposure in vivo to minute amounts of HEMA

2-Hydroxyethyl methacrylate (HEMA) leaks from cured restorations over time. Hence, HEMA can come into contact with cells of the immune system that are present in the oral mucosa and in the dental pulp. In this study, our aim was to develop a model of long-term exposure to minute amounts of HEMA and to record the immunological effects in mice. Osmotic pumps filled with either HEMA (8.2 M or 183 μM) or 0.9% NaCl (control) were implanted subcutaneously into the backs of mice and left in situ for 40 d, during which time the animals were immunized with ovalbumin (OVA). After 40 d, spleens and serum were collected. Splenocyte proliferation in vitro was analyzed by measuring the decomposition of [(3)H]thymidine. Splenocyte cytokine production and serum anti-OVA IgG, IgM and IgA activity were analyzed using ELISAs. Mice exposed to both the higher and the lower HEMA concentrations gained significantly less weight and produced significantly reduced amounts of interleukin-2 (IL-2) in vitro compared with control mice. Mice exposed to the lower HEMA concentration had a significantly reduced concanavalin A-stimulated splenocyte proliferation in vitro and blood anti-OVA IgA activity. In conclusion, long-term exposure to minute amounts of HEMA in vivo affects the general health of mice and suppresses certain immunological functions.