The hazardous effects of formalin and alcoholic fixative in mice: A public health perspective study

Abstract

Formalin is used for different purposes due to its preservation capability. But continuous exposure to formalin may result various health related issues leading to cancer and death. A new alcohol-based fixative, EMA (ethanol, methanol and acetic acid = 3:1:1) could be a safer option in this regard. To compare the health hazards of formalin and EMA, a total 15 adult male mice were randomly distributed into three groups- exposure groups (formalin and EMA) and control group. The mice were subjected to natural inhalation exposure of the fixatives followed by behavioral depression test (forced swimming test), histopathology and serum biochemical tests. Our results showed that the hazardous effects of formalin were remarkably higher than that of EMA. Formalin exposed group showed severe depression (P < 0.001) in the forced swimming test compared to EMA and control groups. Histopathologically, diffuse lymphocytic infiltrations around the lung alveoli and bronchioles and severe inflammation with accumulation of reactive cells in the cerebral cortex were detected in the formalin exposed group, whereas little or no inflammation with fibrinous exudates in the bronchioles was reported in the EMA group and no inflammatory cells were detected in the cerebral tissues. The serum biochemical analysis of the inflammatory mediators (Interleukin-6 and C-reactive protein) revealed that both significantly (P < 0.001) increased in the formalin exposed group compared to EMA and control groups. These results confer that EMA could be a safer option to reduce health hazards of formalin in the workplace environment.

Keywords: C-reactive protein; Cerebrum; EMA; Formalin; Histopathology; Interleukin-6; Lung.

Fig. 1

A natural inhalation exposure of the fixatives in mice.

Fig. 2

Forced swimming test in mice (A = control, B = EMA and C = 10% formalin exposed groups. Bar diagrams (D) illustrating the immobility (floating) period (sec) in the control, EMA and formalin exposed mice during forced swimming test of 300 sec (mean ± SEM). Significant at the level of 5% (P < 0.05).

Fig. 3

Histopathological analysis of lung (A–C) and cerebral tissues (D–F) in mice (A, D = control, B, E = EMA and C, F = formalin exposed groups). Arrow heads and arrows indicate reactive cells and asterisks indicate exudates (A–F). Scale bar in all images (A–F) = 250 μm.

Fig. 4

Bar diagrams illustrating the serum cytokines, interleukin-6 (mean ± SEM) and CRP in the control, EMA and formalin exposed groups. Significant at the level of 5% (P < 0.05).