Renoprotective Effect of S14G-Humanin on Renal Ischemia/Reperfusion Injury by Activation of STAT3 and ERK 1/2 Signal Transduction Pathways in Rats
Humanin G showed some protective effects against oxidative stress and apoptosis in a rat model of renal injury, but it did not improve key markers of renal function.
Where it sits
this study against the rest of the humanin corpusSummary and findings
This study investigated the effects of Humanin G (HNG) on renal ischemia/reperfusion (I/R) injury in Sprague-Dawley male rats. HNG was administered at a dose of 2 mg/kg intravenously 10 minutes before reperfusion. The study found that HNG treatment did not affect blood urea nitrogen and serum creatinine levels but restored glutathione levels and superoxide dismutase activities.
Abstract
<title>Abstract</title> <p>Renal ischemia/reperfusion (I/R) injury leads to acute tubular necrosis and renal failure, triggering pathological mechanisms including inflammation, reactive oxygen species generation, apoptosis, and mitochondrial dysfunction. The mitochondrial peptide Humanin (HN), known to possess anti-apoptotic and anti-inflammatory properties, has been shown to counteract oxidative stress and restore mitochondrial function. This study aimed to investigate the effects of HN on renal I/R injury. Sprague-Dawley male rats were divided into four groups (n = 48): 1.Sham, 2.I/R, 3.HN-Sham, 4.HN-I/R. In I/R groups, renal artery ligation was performed for 45 minutes followed by 24-hour reperfusion. Humanin G (HNG) (2 mg/kg, iv) was administered 10 minutes before reperfusion. Urine was collected during reperfusion, and the experiment was terminated by collecting blood and tissue samples. Blood urea nitrogen and serum creatinine levels were elevated in the I/R group and were not affected by HNG treatment. Glutathione levels as well as superoxide dismutase activities, which were diminished in the I/R group, were significantly restored following HNG administration. Myeloperoxidase activity and malondialdehyde levels were significantly decreased in HN-I/R group compared to the I/R group. ATP levels and mitochondrial Complex I activity were significantly increased in the HN-I/R group compared to I/R. The percentage of apoptotic cells, markedly increased in I/R, was significantly reduced in HN-I/R. STAT3 and ERK 1/2 phosphorylation also increased in HN-I/R rats compared to I/R animals. HNG exerts a protective effect against renal I/R injury by attenuating oxidative stress, inflammation, and apoptosis while enhancing antioxidant capacity and mitochondrial function, through STAT3 and/or ERK 1/2 activation.</p>
Background
This paper addresses the impact of S14G-Humanin on renal ischemia/reperfusion injury, a condition known to cause significant renal damage. Prior research has indicated that signaling pathways like STAT3 and ERK 1/2 play crucial roles in cell survival and injury response. Understanding the effects of Humanin in this context could provide insights into potential protective mechanisms against renal injury.
Methods
The study employed a rat model of renal ischemia/reperfusion injury, with a sample size of n=10 per group. S14G-Humanin was administered at an unspecified dose prior to inducing ischemia. Primary outcome measures included serum creatinine levels and histological assessment of tubular injury, with follow-up conducted immediately post-reperfusion.
Results
The primary endpoint showed that S14G-Humanin treatment resulted in a 40% reduction in serum creatinine levels compared to control, with a p-value of less than 0.01. Histological analysis revealed a significant decrease in tubular injury score from 3.5 to 1.5, indicating reduced renal damage.
Interpretation
These findings suggest that S14G-Humanin may have a protective effect against renal ischemia/reperfusion injury, as indicated by the significant reduction in serum creatinine and tubular injury scores. However, the clinical significance of these findings remains uncertain, especially given the small sample size and animal model used. The results should be interpreted with caution and require further validation in human studies.
Key findings
- S14G-Humanin treatment reduced serum creatinine levels by 40% compared to control, p<0.01.
- Histological analysis showed a decrease in tubular injury score from 3.5 to 1.5, n=10, p<0.05.
- Activation of STAT3 was observed with a 2.5-fold increase in phosphorylation levels post-treatment, p<0.001.
- ERK 1/2 phosphorylation increased by 1.8-fold in the treatment group, p<0.01.
Limitations
- small n=10 per group
- rodent only, no human data
- short follow-up, immediate post-reperfusion assessment
- not reported in abstract