Effects of Mycoplasma pneumoniae infection on airway neurokinin-1 receptor expression in BALB/c mice.

The aim of this study was to establish a BALB/c mouse model of Mycoplasma pneumoniae (MP) infection and to explore the expression of neurokinin-1 receptor (NK1-R) in the trachea and lung tissue and changes in its relative content at different time points (on the 3rd, 7th, 14th, 21st, and 30th days after infection) in MP-infected BALB/c mice. Immunohistochemistry and Western blot analysis were performed to determine NK1-R expression in the trachea and lung tissue and changes in relative content in MP-infected BALB/c mice. After MP infection, the expression of NK1-R on the surfaces of upper tracheal and bronchial epithelial cells, submucosa, and alveolar epithelial cells, as well as around the smooth muscle, was upregulated more significantly in the infection group than in the control group (P < 0.05); NK1-R protein expression was enhanced on the 3rd, 7th, 14th, 21st, and 30th days after infection compared with that of the control group (P < 0.05). NK1-R expression in the trachea, bronchus, and lung tissue increased in MP-infected BALB/c mice, which may explain why wheezing occurs after MP infection.

Cytoskeleton changes of airway smooth muscle cells in juvenile rats with airway remodeling in asthma and the RhoA/ROCK signaling pathway mechanism.

This article aimed to investigate changes in the cytoskeleton of airway smooth muscle cells (ASMCs) in juvenile rats with airway remodeling in asthma. We further investigated the involvement of the RhoA/ROCK signaling pathway mechanism. Rat models of airway remodeling in asthma were established by antigen sensitization with ovalbumin for 2, 4, 6, and 8 weeks. The control group was treated with normal saline instead of ovalbumin. In the intervention group, after 8 weeks of culture, ASMCs were treated with the ROCK-specific inhibitor Y-27632. Immunofluorescence, real-time polymerase chain reaction, and Western blot analyses were used to observe changes in the cytoskeleton (F-actin and α-tubulin) of ASMCs and expressions of RhoA and ROCK. The asthmatic groups had significantly higher average gray values of F-actin in ASMCs compared to the control group (P < 0.01), and these values for the intervention group were significantly lower than those of the 8-week asthmatic group (P < 0.05). Expression levels of the α-tubulin protein in the asthmatic groups were all significantly higher than those of the control group (P < 0.01), and the levels in the intervention group were significantly reduced (P < 0.05). Expressions of RhoA and ROCK mRNA and proteins in all asthmatic groups were significantly higher than those of the control group (P < 0.01). Together, these results demonstrate substantial changes of the ASMC cytoskeleton and abnormal expressions of RhoA and ROCK mRNA and proteins in juvenile rats with airway remodeling in asthma.