Effect of unilateral ureteral obstruction and anti-angiotensin II treatment on renal tubule and interstitial cell apoptosis in rats

Red ginger-extract nanoemulsion modulates high blood pressure in rats by regulating angiotensin-converting enzyme production

Background and Aim:

Red ginger (RG) has reportedly been used in folk medicine for the management and prevention of hypertension. One of the hypertension study models in experimental animals is the unilateral ureteral obstruction (UUO). This study aimed at evaluating the effect of RG-extract (RGE) nanoemulsion on UUO-induced hypertension and angiotensin-converting enzyme (ACE) production in rats.

Materials and Methods:

RG was extracted using ethanol, combined with virgin coconut oil, polysorbate 80, and polyethylene glycol 400 to form the oil phase. The particle sizes of RGE nanoemulsions were analyzed using a particle size analyzer. The UUO method was used to induce chronic kidney disease in rats (504 mg/200 g and 360 mg/200 g b/w per oral for 7 days). The systolic and diastolic blood pressure was determined non-invasively in conscious state by tail plethysmography using an automated blood pressure monitor. ACE in serum was measured using enzyme-linked immunosorbent assay.

Results:

The RGE nanoemulsions exhibited a particle size of32.8 nm and a polydispersity index (PI) of 0.268, indicating a homogenous nanoemulsion. UUO rats treated with RGE nanoemulsion (360 mg/200 g b/w) experienced a significant decrease in both their systolic blood pressure (p<0.05) from 142±1 mmHg to 107±6 mmHg and their diastolic blood pressure from 106±1 mmHg to 84±4 mmHg. Furthermore, treatment with RGE resulted in a 10.80% decrease in the level of ACE.

Conclusion:

The size and the PI of the RGE used in this study suggest a stable and effective distribution of the particle size in the emulsions. RGE nanoemulsions at the dose of 360 mg/200 g bw can be used as potential ACE inhibitors because they were found to decrease the blood pressure of hypertensive UUO rats.

Losartan accelerates the repair process of renal fibrosis in UUO mouse after the surgical recanalization by upregulating the expression of Tregs

Obstructive nephropathy is a common cause for chronic kidney disease. Surgery, which is adopted to promptly relieve the obstruction, is the most important method to save damaged kidneys. However, earlier studies have shown that renal function will continue to deteriorate until the terminal stage after the obstruction' relief. The aim of this study is to explore the renal fibrosis and investigate the effect of losartan on renal fibrosis after the obstruction' relief using an improved mouse model of relief for unilateral ureteral obstruction (RUUO). Experiments carried out using C57BL/6 mice (n = 30) were randomly divided into RUUO + Losartan group, RUUO group and sham group. Using an improved mouse RUUO model, this study revealed that the mouse kidney for 3- or 7-day unilateral ureteral obstruction undergoing the RUUO surgery was still in a state of injury and fibrosis, while losartan could effectively ameliorate renal fibrosis by upregulating the expression of CD4 + CD25 + Foxp3 + regulatory T cells (Tregs) in kidney after the surgery of RUUO.

Thymoquinone alleviates renal interstitial fibrosis and kidney dysfunction in rats with unilateral ureteral obstruction

Unilateral ureteral obstruction (UUO) causes severe renal tubulointerstitial fibrosis. Because of many pharmacologic properties of thymoquinone (TQ), in this study, the effects of TQ against kidney fibrosis and dysfunction were investigated in rats with UUO. Forty male Wistar rats were divided into five groups: Sham operated, UUO, and the animals with UUO treated with losartan, captopril, or TQ. Collagen IV and transforming growth factor (TGF)-β1 expressions, interstitial fibrosis, histological changes, and kidney function were assessed. UUO markedly increased renal expression of TGF-β1 and collagen I and induced interstitial fibrosis (p < .001). Losartan, captopril, or TQ significantly downregulated the expression of these fibrotic markers and interstitial fibrosis (p < .01-p < .001). In UUO group, serum levels of urea and creatinine and protein excretion rate significantly increased, but glomerular filtration rate (GFR) and urine osmolarity showed a significant decrease (p < .001-p < .05). Administration of captopril and TQ caused no significant change in serum urea and protein excretion rate. Unlike losartan and captopril, TQ caused no significant alteration in GFR compared with Day 1. Losartan caused significant increases in serum urea and creatinine but significant decrease in urine osmolarity. TQ could be regarded as a potent therapeutic agent for treatment of UUO-induced kidney fibrosis and dysfunction.

Nigella sativa extract is a potent therapeutic agent for renal inflammation, apoptosis, and oxidative stress in a rat model of unilateral ureteral obstruction

Unilateral ureteral obstruction (UUO) is a well-established experimental model to evaluate renal interstitial fibrosis. Current study is aimed to investigate the effects of Nigella sativa (NS) extract and renin-angiotensin system (RAS) blockade against kidney damage following UUO in rats. In this study, the rats received intraperitoneal injection of losartan (15 mg/kg), captopril (30 mg/kg), and two doses of NS extract (200 and 400 mg/kg) for 18 consecutive days. At the fourth day of the experiment, laparotomy was performed, and the left ureter was ligated. Sham-operated animals received saline as vehicle, and laparotomy without ureteral ligation was done. UUO was associated with significant increase in the expression of renal angiotensin II and monocyte chemoattractant protein-1, concentration of malondialdehyde and tumor necrosis factor-α, and the number of apoptotic cells when compared with sham group. Renal total thiol content and the activity of antioxidant enzymes were significantly reduced as compared with the sham group. However, treatment of obstructed rats with losartan, captopril, and NS extract significantly improved these renal impairments when compared with UUO group. Thus, NS extract, a potent antioxidant and anti-inflammatory herb, is a therapeutic agent to treat the UUO-induced kidney damage comparable with the well-known RAS inhibitors captopril and losartan.

Exosomal proteomic analysis reveals changes in the urinary proteome of rats with unilateral ureteral obstruction

Congenital urinary tract obstruction (UTO) is a commonly noted disorder with the potential to cause permanent loss of renal function. Due to the possibility of spontaneous resolution, postnatal management strategies require lengthy and invasive surveillance methods to monitor the status of renal function and severity of obstruction. Here, a quantitative proteome analysis of urinary exosomes from weanling rats with surgically introduced UTO identifies a number of candidate biomarkers with the potential to improve diagnostic and prognostic methods for this disease. Using gel-assisted digestion coupled to liquid chromatography/tandem mass spectrometry (LC–MS/MS), 318 proteins were identified. Relative protein quantitation by spectral counting showed 190 proteins with significant changes in abundance due to either partial or complete obstruction. Numerous proteins identified here have been shown to be similarly altered in abundance in other renal diseases that cause tubule apoptosis and interstitial fibrosis. Extrapolating the role of the proteins showing quantifiable changes in abundance here from other forms of renal disease suggests they have potential for clinical applicability as biomarkers of congenital UTO. Included in the list of identified proteins are markers of apoptosis, oxidative stress, fibrosis, inflammation, and tubular cell damage, which are commonly associated with UTO. This study therefore provides a number of candidate biomarkers that, following validation in children experiencing UTO, have the potential to improve postnatal management of this disease.

Losartan attenuates renal interstitial fibrosis and tubular cell apoptosis in a rat model of obstructive nephropathy

Ureteral obstruction leads to renal injury and progresses to irreversible renal fibrosis, with tubular cell atrophy and apoptosis. There is conflicting evidence concerning whether losartan (an angiotensin II type I receptor antagonist) mitigates renal interstitial fibrosis and renal tubular epithelial cell apoptosis following unilateral ureteral obstruction (UUO) in animal models. The aim of this study was to investigate the effect and mechanism of losartan on renal tubular cell apoptosis and renal fibrosis in a rat model of UUO. The rats were subjected to UUO by ureteral ligation and were treated with dimethyl sulfoxide (control) or losartan. The controls underwent sham surgery. The renal tissues were collected 3, 5, 7 and 14 days after surgery for measurement of various indicators of renal fibrosis. UUO increased the expression levels of α‑smooth muscle actin and collagen I, and the extent of renal tubular fibrosis and apoptosis in a time‑dependent manner. Losartan treatment partially attenuated these responses. Progression of renal interstitial fibrosis was accompanied by phosphorylation of signal transducer and activator of transcription 3 (STAT3) and altered the expression levels of two apoptosis‑related proteins (Bax and Bcl2). Losartan treatment also partially attenuated these responses. The results indicated that losartan attenuated renal fibrosis and renal tubular cell apoptosis in a rat model of UUO. This effect appeared to be mediated by partial blockage of STAT3 phosphorylation.