Figure 2. Influence of aging on ICCs in the mouse GI tract. The c-kit immunoreactivity (red) showed ICCs network in the whole-mount preparation. The sparseness of cellular network in stomach (A), jejunum (B) and colon (C) appeared at 16, 20 and 24 mo, respectively. In high magnification of 2-mo-old stomach (D), c-kit(+) cells with round or oval cell bodies (left figure, arrows) and cell processes (right figure) including primary (arrow), secondary (arrowhead) and tertiary processes (double arrow) were clearly seen by c-kit immunofluorescence staining. Statistical analysis showed that ICCs density decreased over time from 16 mo in stomach, 20 mo in jejunum and 24 mo in colon (E). Expressions of c-kit protein in 2-, 12-, 16-, 20- and 24-mo-old mice in different organs of GI tract were examined by western blotting (F-H). Densitometric analysis of protein expressions normalized to β-actin and the downtrend of c-kit expression was coincident with ICC-density in all three organs. Statistical analysis was performed using one-way analysis of variance and data were represented as mean ± SD, statistical significance is: (E) ## P < 0.01, ### P < 0.001 compared with previous stomach group; * P < 0.05, *** P < 0.001 compared with previous jejunum group; ††† P < 0.001 compared with previous colon group; (F-H) ## P < 0.01, ### P < 0.001 compared with 2-mo-old group; ** P < 0.01, *** P < 0.001 compared with previous group; n=5 mice per group. Abbreviation: Sto, stomach; Jej, jejunum; Co, colon.