Table 5.

Dynamic Changes of PMN Infiltration into the Lung Tissue Before and After Inoculation of P. aeruginosa in Two Groups of Rats

Time point (h)	Young group (20,000 μm2 mean ± SD)	Aged group (20,000 μm2 mean ± SD)	t a	P value
0	6.75 ± 0.96	4.75 ± 0.50	0.168	0.010
2	18.50 ± 3.70	9.75 ± 2.50	3.921	0.0087
6	28.25 ± 2.99	18.50 ± 3.87	3.987	0.007
9	55.00 ± 5.77	27.75 ± 3.77	7.901	<0.001
12	53.75 ± 4.79	39.50 ± 4.43	4.367	0.005
24	32.75 ± 3.30	24.50 ± 1.73	4.423	0.004

Data presented as mean ± SD

^aNon-parametric test