Figure 4.

Cathepsin L is an important mediator of mammary gland involution. (a) Immunoblot showing the complete deletion of cathepsin L in cathepsin L^−/− (ctsl^−/−) glands compared with the controls (ctsl^+/+) at 72-h involution. Tubulin is shown as loading control. (b) H&E sections and (c) quantification of the percentage of area occupied by adipocytes at 72-h involution clearly show the delay in involution in ctsl^−/− mice compared with the controls. Quantification has been performed on two and three independent biological repeats for the control and the ctsl^−/− mice, respectively. All values are means±S.E.M. (**P<0.01, as determined by Student's t-test; scale bar, 100 μm). (d) Immunohistochemical analysis of the adipocytes (stained with perilipin, red) and epithelium (stained with E-cadherin, green) in 72 h of involution samples. Nuclei are stained with Hoechst. Scale bar, 100 μm