Fig. 5.

Rapamycin treatment induces increased apoptosis and luminal shedding of cystic epithelial cells. Orpk-rescue (Tg737^orpk/orpk;TgRsq) mutant and orpk-heterozygous-rescue (Tg737^orpk/+;TgRsq) control mice were treated with rapamycin or vehicle as indicated. Renal tissue sections were processed and analyzed for the presence of apoptotic cells by TUNEL. (A) TUNEL-positive, cyst-lining epithelial cells were observed in sections of nontreated Tg737^orpk/orpk;TgRsq mutant mice, whereas a significant increase in TUNEL-positive, cyst-lining and cyst-luminal epithelial cells were observed in sections of rapamycin-treated Tg737^orpk/orpk;TgRsq mutant mice. (B) Quantification of TUNEL-positive cells in renal sections derived from vehicle or rapamycin-treated orpk-rescue mutant animals expressed as an average of TUNEL-positive cells per cyst (n = 4 kidneys). ∗∗∗, P < 0.001.