Protective effect of tea polyphenols on renal ischemia/reperfusion injury via suppressing the activation of TLR4/NF-κB p65 signal pathway.

Tea polyphenols (TP) was investigated in rats for its protective effect on renal ischemia/reperfusion injury (RIRI). Rats were randomized into groups as follows: (I) sham group (n=10); (II) RIRI group (n=10); (III) RIRI+TP (100mg/kg) group (n=5); (IV) RIRI+TP (200mg/kg) group (n=5); (V) RIRI+TP+ Astragalus mongholicus aqueous extract (AMAE) (300 mg/kg+100mg/kg) group (n=5). For the IRI+TP groups, rats were orally given with tea polyphenols (100, 200 and 300 mg/kg body weight) once daily 10 days before induction of ischemia, followed by renal IRI. For the sham group and RIRI group, rats were orally given with equal volume of saline once daily 10 days before induction of ischemia, followed by renal IRI. Results showed that tea polyphenol pretreatment significantly suppressed ROS level and MDA release. On the other hand, in rats subjected to ischemia-reperfusion, the activities of endogenous antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GSH-Px) showed recovery, whereas the levels of urea nitrogen and serum creatinine were reduced by administration of tea polyphenols orally for 10 days prior to ischemia-reperfusion. Moreover, tea polyphenol pretreatment significantly decreased TLR4 and NF-κB p65 protein expression levels in RIRI rats. At the same time, tea polyphenol pretreatment attenuated the increased level of serum IL-1β, IL-6, ICAM-1 and TNF-α, and enhanced IL-10 production in RIRI rats. Furthermore, tea polyphenol pretreatment significantly decreased renal epithelial tubular cell apoptosis induced by renal ischemia/reperfusion, alleviating renal ischemia/reperfusion injury. These results cumulatively indicate that tea polyphenol pretreatment could suppress the TLR4/NF-κB p65 signaling pathway, protecting renal tubular epithelial cells against ischemia/reperfusion-induced apoptosis, which implies that antioxidants may be a potential and effective agent for prevention of the ischemic/reperfusion injury through the suppression extrinsic apoptotic signal pathway induced by TLR4/NF-κB p65 signal pathway. Moreover, supplement of AMAE can increased renal protection effect of TP.

Li YW ，Zhang Y ，Zhang L ，Li X ，Yu JB ，Zhang HT ，Tan BB ，Jiang LH ，Wang YX ，Liang Y ，Zhang XS ，Wang WS ，Liu HG ... -  《-》

Magnesium isoglycyrrhizinate protects against renal‑ischemia‑reperfusion injury in a rat model via anti‑inflammation, anti‑oxidation and anti‑apoptosis.

Zhao Z ，Tang Z ，Zhang W ，Liu J ，Li B ... -  《-》

Protective Effect of the Total Flavonoids from Rosa laevigata Michx Fruit on Renal Ischemia-Reperfusion Injury through Suppression of Oxidative Stress and Inflammation.

Zhao L ，Xu L ，Tao X ，Han X ，Yin L ，Qi Y ，Peng J ... -  《MOLECULES》

Nephroprotective effect of telmisartan in rats with ischemia/reperfusion renal injury.

We investigated the protective effect of telmisartan, an angiotensin II receptor antagonist, against ischemia/reperfusion renal injury in rats. Bilateral ischemia was induced by clamping both renal vascular pedicles for 45 min followed by reperfusion for 3 h. Untreated rats exposed to ischemia/reperfusion showed significant elevations in blood urea nitrogen and serum creatinine levels, renal tissue levels of malondialdehyde, tumor necrosis factor-alpha and nitric oxide, and caspase-3 activity. This was associated with significant decreases in renal reduced glutathione level, catalase and superoxide dismutase activities. Also, significant increases in serum and renal tissue levels of homocysteine were detected following ischemia/reperfusion. Pre-ischemic treatment with telmisartan (0.3 mg/kg/day, i.p.) for 7 consecutive days significantly attenuated the increases in blood urea nitrogen, serum creatinine, renal malondialdehyde, tumor necrosis factor-alpha, nitric oxide, caspase-3 activity, and serum and renal homocysteine levels, and significantly restored the renal antioxidant defenses. In addition, light and electron microscopic examinations revealed that telmisartan pre-treatment markedly ameliorated ischemia/reperfusion-induced renal tissue damage. It was concluded that telmisartan, through its antioxidant, anti-inflammatory and antiapoptotic effects, can be considered a potential candidate to protect against acute ischemia/reperfusion renal injury.

Fouad AA ，Qureshi HA ，Al-Sultan AI ，Yacoubi MT ，Al-Melhim WN ... -  《-》

Attenuation of renal ischemia/reperfusion injury by a polysaccharide from the roots of Dipsacus asperoides.

Renal ischemia-reperfusion (I/R) injury is a leading cause of acute renal failure and one of the major problems after I/R is the production of large amounts of reactive oxygen species (ROS). The present study was performed to evaluate the interference of a polysaccharide (WRDAP-1) from the roots of Dipsacus asperoides in I/R-induced renal injury in rats to determine whether it was mediated by the protective mechanism against oxidative stress to kidney. In vitro experiment, WRDAP-1 exhibited a potent scavenging ability on superoxide radical and hydroxyl radical. Renal protective effect of WRDAP-1 was evaluated in serum levels of blood urea nitrogen (BUN), creatinine, lactate dehydrogenase (LDH), superoxide dismutase (SOD) and serum malonaldehyde (MDA), as well as some renal tissue antioxidant enzymes activities like SOD glutathion peroxidase (GSH-Px) and catalase (CAT). Pretreatment with WRDAP-1 produced reduction in serum levels of BUN, creatinine and LDH caused by I/R injury and significantly improved serum enzymatic activity of SOD and serum MDA level. Additionally, antioxidant enzymes activities of SOD, GSH-Px and CAT in renal tissue were also elevated by WRDAP-1. Collectively, administration with WRDAP-1 significantly improved renal function of I/R rats especially in the rats treated with higher dose of the polysaccharide. Therefore the findings of this study imply that the protective effect of WRDAP-1 against renal I/R injury in rat kidneys could be due to its antioxidant and free radical scavenging activities. WRDAP-1 seems to be a highly promising agent for protecting tissues from oxidative damage and preventing kidney damage due to renal I/R.

Cong G ，Cui L ，Zang M ，Hao L ... -  《-》