Figure 3.

Histopathologic development in mice inoculated with H1N1 virus. The experiment set up is the same as in Figure 2. At 1 day after, the presentations were similar in all groups and there was little vacuolar degeneration of bronchi and bronchiole epithelium cells(D, E, F). At 3 days and 5 days after inoculation, the damage was severe in the 4-week group (G, J) than that of 6-month (H, K) and 1-year group (I, L). Severe interstitial edema was seen around blood vessels, apparent injured parenchyma and degenerated alveolar epithelial cells were seen with more inflammatory cells infiltration. The histological damage (M) was semi-quantified (n = 3 mce in each group). * and ***indicate P < 0.01 and P < 0.001 respectively relative to the corresponding the different age group mice with 4 week age group mice. Mean ± SEM. Magnification,× 200 (A-L).