Irritant and adjuvant effects of gaseous formaldehyde on the ovalbumin-induced hyperresponsiveness and inflammation in a rat model

Abstract

FA may be an irritant as well as serve as an adjuvant for the onset of asthma or asthma-like symptoms.

Adjuvant effects of gaseous formaldehyde on the hyper-responsiveness and inflammation in a mouse asthma model immunized by ovalbumin

“…Jung et al (2007) reported that FA exposure alone results in an increased count of eosinophils, higher levels of IgE and interleukin (IL)-4, and lung inflammation in mice. Similar results were also found in a rat model (Qiao et al, 2009). When combined with ovalbumin (OVA) sensitization, FA exposure can induce the following: increased serum levels of anti-OVA IgE in a mouse model (Tarkowski and Gorski, 1995); a high ratio (i.e., 10/12) in guinea pigs with positive signs by sensitive pulmonary function testing (Riedel et al, 1996); and, lung histological changes (i.e., pulmonary inflammation, airway remodeling), increased airway resistance, eosinophil infiltration, and increased IL-4 levels in bronchoalveolar lavage fluid (BALF) in rats (Qiao et al, 2009).…”

“…FA exposure for 6 or 8 h every day lasting 2 or 3 week has been found to successfully establish FA-induced asthma (Riedel et al, 1996;Jung et al, 2007;Qiao et al, 2009). Exposure times that are too long (Fujimaki et al, 2004) or too short (Franco et al, 2006(Franco et al, , 2009(Franco et al, , 2010 may result in different conclusions.…”

“…Nevertheless, both this and the Qiao et al (2009) papers are markedly improved in terms of indices determination and model development than those proposed by other groups, i.e., the models mentioned in many other papers might be defined as 'animal models' used for related toxicity investigations, but not specifically (as an 'asthma model') for the study of the pathogenesis of asthma. Specifically, those papers only provided indirect evidence from some other physiologic aspect, e.g., the aim of studies by Jung et al (2007) and Fujimaki et al (2004) was to examined the effect of FA on inflammation, while that of Franco et al (2006Franco et al ( , 2009Franco et al ( , 2010 was to ascertain the influence of FA on general lung function.…”

“…Some of the previous studies (Franco et al, 2006(Franco et al, , 2009(Franco et al, , 2010 did not indicate the real FA exposure concentration in units of ppm or mg/m 3 and the actual exposure levels may have been far higher than that in real life. Consequently, the biological effects such as the IgE or IgG 1 expression and eosinophil count in BALF were different among the studies (Tarkowski and Gorski, 1995;Riedel et al, 1996;Jung et al, 2007;Qiao et al, 2009; see Table 1). …”

“…Animals were anesthetized intraperitoneally with 90 mg/kg sodium pentobarbital (Urchen, Shanghai, China) and then connected to a computer-controlled ventilator via a cannula that had been surgically implanted in the trachea using protocols we have described previously (Qiao et al, 2009). The respiratory rate was pre-set at 95 times/min and the expiration/inspiration time ratio was set at 1.5:1.…”