Objectives: Human and animal studies have shown a close relationship between obesity and asthma severity. Here, we examined the effects of diet-induced obesity (DIO) on the expression levels of IL-1β, IRAK-1 and TRAF-6 mRNA in male Wistar rats tracheal after sensitization with ovalbumin (OVA).
Materials and methods: Twenty male Wistar rats divided to four groups, included, control group with normal diet (C+ND), OVA-sensitized group with normal diet (S+ND), control group with high-fat diet (C+HFD), and OVA-sensitized group with high-fat diet (S+HFD). All animals fed for 8 weeks with standard pelts or high-fat diet, and then were sensitized and challenged with OVA or saline for another 4 weeks with designed regimens. At the end of study, trachea isolated and examined for expression levels of IL-1β, IRAK-1 and TRAF-6 mRNA with RT-PCR method.
Results: Diet-induced obesity groups developed increased weight, obesity indexes and lipid profiles (P<0.05 to P<0.001). The expression levels of IL-1β mRNA in OVA-sensitization groups (S+ND and S+HFD) showed a significantly increased when compared with control group. Also in S+HFD group, expression level of TRAF-6 mRNA was higher than other groups (P<0.001). IRAK-1 expression level was high in S+HFD compared with control group.IL-1β and TRAF-6 mRNA correlated positively with obesity indexes.
Conclusion: The results showed that DIO causes overexpression of IL-1β, IRAK-1 and TRAF-6 mRNA in an experimental model of asthma. Our results suggested that in obese-asthmatic conditions locally production and activation of pro-inflammatory agents can be increased. These findings showed that possible mechanism for obesity-asthma relationships.
Keywords: Asthma; IL-1β; IRAK-1; Obesity; TRAF-6; Tracheal.