Chronic Heat Stress Weakened the Innate Immunity and Increased the Virulence of Highly Pathogenic Avian Influenza Virus H5N1 in Mice
Figure 1
Analysis of the local immunity in the respiratory tract of mice. (A) Representative sections from each group were stained by H&E after exposed to 38 ± 1°C or 24 ± 1°C over 21 days (400×). (a) Normal nasal sections from TN mice. (b) Nasal lesions from CHS mice. Solid arrows indicate sebaceous gland hyperplasia. (c) Normal tracheal sections from TN mice. (d) Tracheal lesions from CHS mice. Solid arrows indicate erythrocytes infiltrated in the tube cavity of the trachea and unshaded arrows indicate the dropout of trachea epithelium cells. (e) Normal lung section from TN mice.(f) Lung lesion from CHS mice. Solid arrows indicate alveolar expansion and unshaded arrows indicate a reduction and necrosis of mucous epithelial cells. (B) The mRNA levels of HSP70 in the lungs were determined by qPCR at various time-points. (C) PAM counting from BAL was performed after exposure to 38 ± 1°C or 24 ± 1°C for 21 days. These results are the mean ± SD values obtained from three distinct animals and are representative of three independent experiments. *indicates when compared with the TN group. TN: thermally neutral; CHS: chronic heat stress.
