In rats, breathing formaldehyde lowered a longevity‑related protein called humanin, but giving the antioxidant N‑acetylcysteine (NAC) brought humanin levels back up toward normal. The same protective effect was seen for another protein, endostatin.

People are constantly exposed to formaldehyde, a volatile and poisonous gas, in indoor environments. In particular, anatomists, pathologists, histologists, and those involved in embalming are exposed to higher amounts of formaldehyde continuously due to their work. This study aimed to investigate the effect of N-acetylcysteine on endostatin and humanin values in male rats exposed to experimental formaldehyde. In the study, 28 male Spraque-Dawley rats aged 12-14 weeks (seven animals in each group: control group, formaldehyde group, N-acetylcysteine group, formaldehyde+N-acetylcysteine group) were used. Four weeks later, the animals were sacrificed by decapitation. Following decapitation, endostatin and humanin levels in the serum of rats were studied by the enzyme-linked immunoassay (ELISA) method. In all analyses, p<0.05 was accepted as statistically significant. Humanin and endostatin values were checked in the serum of rats. When humanin levels were compared between groups, a statistically significant difference was found between the formaldehyde group and both the control group (p<0.05) and the N-acetylcysteine group (p<0.05). In the formaldehyde+N-acetylcysteine group, it was determined that the humanin level was impaired due to formaldehyde exposure, approaching the control group values with the administered N-acetylcysteine. When the endostatin level was compared between the groups, a statistical significance (p<0.05) was found only between the formaldehyde group and the N-acetylcysteine group. In the formaldehyde+N-acetylcysteine group, it was determined that the endostatin level was impaired due to formaldehyde exposure, approaching the control group values with the administered N-acetylcysteine. In this study, the effects of N-acetylcysteine on humanin and endostatin on rats exposed to formaldehyde were demonstrated for the first time. Formaldehyde exposure negatively affected humanin and endostatin levels in rat sera. N-acetylcysteine ameliorated the negative effects of formaldehyde, bringing humanin and endostatin levels closer to the healthy control group.