| Formaldehyde (FA), a kind of popular indoor air pollutant, is also an endogenous chemical. FA has become one of the most important and serious indoor air pollutants for its characteristics of extensive sources, serious toxicity, high level pollution and long-term duration. The effects of FA on human health include eyes and upper respiratory irritancy, allergy and immunological effects, genotoxicity and cancer, neurotoxicity et al. and only high dose FA can cause the toxic action, however, what kind of effect did it at low dose FA, it has been known a little so far. It was known that low dose FA can induce adaptive response. In order to explore the cell proliferation effect at low dose FA, this study used HEK293 cells as the experiment objects, applied morphologic observation, MTT assay and flow cytometry to detect the cell proliferation of HEK293 cells. Nowadays apoptosis has become one of the hottest spots in the environmental toxicology. There were many reports on which FA induced apoptosis, however, it had only limited to speculate on the mechanism that FA induced apoptosis, and it had demand some experiment attestation to prove the fact whether formaldehyde could induce apoptosis or not. In order to explore whether formaldehyde could induce apoptosis or not, this study used Hela cells as the experiment objects, applied morphologic observation, MTT assay and flow cytometry to detect the apoptosis of Hela cells.The results:1. Effects of the cell proliferation at low dose FAAdaptive response is a ubiquitous phenomenon in biology. There were some reports on alkylation inducing adaptive response many years ago, however, it had still arose the attention of many laboratories. Low dose FA can induce adaptive response, there were the protection effect to the some enzymes at low dose FA, and there was some influence to the growth state of cells.This study used HEK293 cells as the experiment objects, applied MTT assay and flow cytometry to detect the cell proliferation and cycle. Results showed that the percentage of phase G1(28.4%) was decreased 8.6% compared with that of the control group(37.0%), and the percentage of phase S(48.5%) was increased 7.8% compared with that of the control group(40.7%) after the HEK293 cells were treated by the low dose (60μmol/L) FA for 12 hours, but the percentage of phase G1(38.1%) was increased 1.1% compared with that of the control group(37.0%), and the percentage of phase S(40.2%) was decreased 0.5% compared with that of the control group(40.7%) after the HEK293 cells were treated by the high dose(120μmol/L) FA for 12 hours, These experiments showed that Formaldehyde could promote the cell proliferation of the HEK293 cells at the low dose(60μmol/L) and inhibit the cell proliferation of the HEK293 cells at the high dose(120μmol/L).2. Study on apoptosis of Hela cell induced by formaldehydeNowadays apoptosis has become one of the hottest spots in the environmental toxicology. In order to explore whether formaldehyde could induce apoptosis or not, this study used Hela cells as the experiment objects, which were treated with different concentrations of formaldehyde for 24h. This experiment applied morphologic observation, MTT assay and flow cytometry to detect the apoptosis of Hela cells. Results showed that Hela cells' proliferation was significant inhibited after treated with FA at low concentrations(≤0.2mmol/L) in 24h(p<0.05), but morphological change of cells was little, and cell nucleus DNA was no damage. However, Hela cells' proliferation was statistically significant inhibited after treated with FA at high concentrations(≥0.4mmol/L) in 24h(p<0.01), morphological change of cells gradually blurred, a small amount of cells shrank into circular, and would cause regular break of cell nucleus DNA, apoptosis rate increased along with FA concentrations increased. These experiments showed that FA at high concentration treatment Hela cell for 24h, would induce cell apoptosis; And there was a certain dose-dependent relationship between FA concentrations and apoptosis rate.
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