PMC

Neonatal cyst formation is dependent on pI:pC dosing schedule. (A) Timeline for pI:pC induction experiments. (B) Figures shown are representative H&E-stained kidney sections from P35 Pkd1^flox/flox;Mx1Cre male and female mice induced with 250 μg pI:pC. Variables in the induction schedule are represented as injection at Days P10, P12 or both P10/P12 and the volume of pI:pC delivered in 12.5 or 25 μl.

Triptolide preserves renal function. BUN values were measured from cystic mice over time on both P22 and P35 (n = 13 DMSO, n = 11 triptolide; asterisk indicates significance at P < 0.035 by Student’s t-test). Baseline refers to the average BUN values of non-cystic mice treated with DMSO or triptolide taken on P22. Double dagger indicates P < 0.0001 for the increase in BUN from baseline through P35 for DMSO by ANOVA using Bonferroni’s post hoc analysis (α = 0.05). There was no increase in BUN from baseline through P35 (P = 0.10322) with triptolide treatment.

Widespread liver cysts are present 5 months post-Pkd1 adult deletion. Representative H&E-stained liver sections (×40 magnification) from Pkd1^flox/flox wild-type (WT) or induced Pkd1^flox/flox;Mx1Cre cystic (Cy) mice. Normal hepatic structures such as the central vein and portal triad can be observed in the WT sections. H&E kidney sections are also represented (×8 magnification) from WT and cystic mice. All tissues were obtained at 5 months following 1× 250 μg pI:pC induction at P30.

Kidney cystic burden increases rapidly in the Pkd1^flox/flox;Mx1Cre neonatal induction model. (A) Representative H&E-stained kidney sections from Pkd1^flox/flox;Mx1Cre mice showing progression of cyst formation following pI:pC induction. (B) Contiguous T2-weighted axial slices from non-cystic (Pkd1^flox/+) and cystic (Pkd1^flox/flox;Mx1Cre) male mice obtained using a multi-slice RARE sequence. Kidneys were harvested at P35 following pI:pC induction at P10/P12; 25 μl. Imaging parameters at 9.4 T were as follows: in-plane resolution = 100 × 100 μm, slice thickness = 500 μm, effective echo time = 34 ms and recycle time = 5 s. (C) Representative H&E-stained liver sections from P35 Pkd1^flox/+ (WT) and Pkd1^flox/flox;Mx1Cre (Cystic) mice (inset shows ×40 magnification of cholangiocyte-derived liver cysts). Alkaline phosphatase (ALP) activity from blood serum was also analysed as an indicator of liver function (WT n = 3, cystic n = 7; P = 0.9776).

Triptolide reduces cystic burden in the Pkd1^flox/flox;Mx1Cre model of ADPKD. (A) Representative H&E-stained P35 kidney sections from wild-type Pkd1^flox/+ (WT) and cystic Pkd1^flox/flox;Mx1Cre (Cy) mice treated with DMSO or triptolide (×8 magnification). Far right panels are representative H&E-stained outer cortex kidney sections showing areas of small cyst formation (×40 magnification). (B) Analysis of kidney cyst number, % cystic burden and average cyst size (kidneys: n = 42 DMSO and n = 40 triptolide) from cystic P35 Pkd1^flox/flox;Mx1Cre mice. (C) Frequency distribution of the number of cysts present of varying size. Cyst size is represented in pixels as determined from Image J analysis software (kidneys: n = 42 DMSO and n = 40 triptolide). (D) The percent of proliferating cells per cyst as assessed by Ki-67 immunohistochemical staining. Cells per cyst were counted from sagittal cross sections taken from DMSO- or triptolide-treated mice (The number of total cysts analysed for DMSO was 283 and for triptolide was 212). (E) Analysis of kidney weight as a percentage of body weight (%BW) from cystic (n = 21 DMSO, n = 20 triptolide) and non-cystic (WT) (n = 24 DMSO, n = 26 triptolide) P35 mice treated with either DMSO or triptolide. All mice were induced at P10/P12 using a 25 μl pI:pC volume. For all panels: *P < 0.0001, **P < 0.003 and ^#P < 0.05 by Student’s t-test.