Apoptosis signaling pathway in a subtotal nephrectomy rat model

Area of Science:

• Nephrology
• Cell Biology
• Molecular Biology

Background:

• Chronic kidney disease (CKD) progression involves complex cellular mechanisms.
• Apoptosis, or programmed cell death, is implicated in renal injury and fibrosis.

Purpose of the Study:

• To investigate the role and mechanisms of apoptosis and its signaling pathways in a 5/6 nephrectomy rat model (SN(x)).
• To analyze the temporal changes in apoptosis and caspase expression following subtotal nephrectomy.

Main Methods:

• Established a 5/6 nephrectomy rat model.
• Quantified apoptosis using in situ end labeling (TUNEL).
• Assessed mRNA and protein levels of caspase-3, -8, and -9 via RT-PCR and Western blotting at multiple time points.

Main Results:

• SN(x) rats developed glomerular sclerosis and renal interstitial fibrosis.
• Significantly higher apoptotic cell counts were observed in glomeruli, tubules, and interstitium of SN(x) rats compared to controls (P < 0.01).
• mRNA and protein levels of caspase-3, -8, and -9 were upregulated in SN(x) rats, with distinct peaks at weeks 4 and 40; caspase-9 showed greater amplitude than caspase-8.

Conclusions:

• The development of the 5/6 nephrectomy rat model is associated with apoptosis in renal glomeruli, tubules, and interstitium.
• Both death receptor and mitochondria-mediated apoptosis signaling pathways are involved.
• The mitochondria signaling pathway appears to play a predominant role in the observed renal injury.