Effects of formaldehyde inhalation on humoral immunity and protective effect of Nigella sativa oil: An experimental study

Abstract

Aim: This study was carried out to determine the effects of formaldehyde (FA) inhalation on the humoral immunity of rats and the protective effect of Nigella sativa (NS) oil. Materials and Methods: The rats (n = 33) were divided into five groups, with five animals in the control group (FA-free air) and seven in the other four groups. Group FA I was exposed to FA (5 ppm), group FA NS I was treated with NS and exposed to FA (5 ppm), group FA2 was exposed to FA (10 ppm), and group FA + NS2 was treated with NS and exposed to FA (10 ppm). At the end of a 4-week study period, blood samples were collected. Enzyme-linked immunosorbent assay was used to determine the levels of serum total immunoglobulin A (IgA), total immunoglobulin M (IgM), total immunoglobulin G (IgG), and complement 3 (C3). Results: FA inhalation significantly increased serum IgA, IgM, and C3 levels and decreased serum IgG levels compared with the control group. NS administration decreased serum IgA, IgM, and C3 levels, which were induced by FA inhalation. Conclusion: FA inhalation significantly increased acute antibody responses and C3 levels in a dose-dependent manner compared with the control group. FA inhalation decreased the secondary immune response compared with the control group. Levels of acute antibody responses and complement following exposure to FA inhalation returned to normal following treatment with NS (immunoregulatory effect). However, NS did not affect the secondary immune response.