The toxicity of continuous long-term low-dose formaldehyde inhalation in mice

Although the toxicity of high-dose formaldehyde (FA) inhalation has been extensively analyzed in animals, the effect of continuous long-term exposure to low-dose FA has not been well documented. This study aims to evaluate the toxicity of continuous long-term low-dose FA inhalation in mice. Forty-eight Kunming male mice were equally randomized to three groups according to the dose of FA inhalation exposure: a control (0 mg/m³) group, a low-dose (0.08 mg/m³) group and a high-dose (0.8 mg/m³) group. The mice have been selected to expose to FA for different consecutive days at 24 h/day. The learning and memory functions, pathological changes in the lung and liver, and the percentage of CD4 ⁺ T and CD8 ⁺ T cells were observed and analyzed. It was found that continuous long-term inhalation of FA at relatively low doses could impair the learning and memory functions and induce pathological changes in the lung and liver, but did not seem to significantly affect the number of immune (CD4 ⁺ T and CD8 ⁺ T) cells.