Effect of thiomersalate exposure on the behaviour and humoral immunity of premature rats

Abstract

Objective To discover the influence of thiomersalate exposure on the behavior and humoral immunity of premature rats. Methods According to common thiomersalate dose of vaccine used in human, the surface conversation method was used to change the dose to 1, 2, 3, 4 times for rats(32.8, 65.6, 98.4 and 131.2 μg/kg), and the thiomersalate was separately injected to the gluteus maximus of premature rats respectively, which were delivered on the 20th day of gestation by cesarean for the injection on day 1(premature). Simultaneously, saline was injected to the control group.On day 44 to 48 after injection, the Morris water maze test was used to evaluate the spatial learning and memory abilities of rats and on the post-injection day 49, immunoglobulin content in rat blood and cerebrospinal fluid was measured. Results The spatial learning abilities of rats in 131.2 μg/kg group and the memory abilities in 65.6 μg/kg, 98.4 μg/kg and 131.2 μg/kg group were significantly weaker than those in 9 g/L saline group(all P<0.001). The immunoglobulin content in blood and cerebrospinal fluid changed in different groups exposed to thiomersalate.The levels of IgG, IgA, IgE, IgM in 98.4 μg/kg group and 131.2 μg/kg group rose significantly higher than those in 9 g/L saline group(all P<0.01). Analysis of rectilinear correlation between the immunoglobulin and learning abilities of rats revealed that IgG, IgA, IgE levels in the blood were correlated with the spatial learning abilities(r=0.36, 0.47, 0.50, all P<0.05)and the levels of IgG, IgA, IgE, IgM in blood were rectilinear correlated with the memory abilities of rats(r=-0.39, -0.43, -0.49, -0.38, all P<0.05). In rats'cerebrospinal fluid, IgG, IgA, IgE, IgM levels were rectilinear correlative with both the spatial learning and memory abilities(r=0.48, 0.59, 0.54, 0.41, all P<0.05; r=-0.39, -0.61, -0.57, -0.44, all P<0.05). Conclusion With the dose of thiomersalate increased, the learning and memory and humoral immunity are sustained damaged for premature rats. Key words: Thiomersalate; Humoral immunity; Premature rat