Protective Effects of Astaxanthin on Nephrotoxicity in Rats with Induced Renovascular Occlusion.

Background: Various effects of Astaxanthin were shown in the studies, including its antioxidant, anti-inflammatory, anti-tumor and immunoregulatory effects.

Objective: The aim of this study was to evaluate the beneficial effects of Astaxanthin on renovascular occlusion induced renal injury and to investigate the possible mechanisms.

Methods: The rats were randomly assigned into three groups as follows: Group 1: control group (n=12), Group 2: renal ischemia-reperfusion injury group (n=12), Group 3: renal ischemia-reperfusion + asthaxantine treated group (n=12). The control group and the renal ischemia-reperfusion group were given 2cc/kg/g olive oil for 7 days before establishing ischemia to renal tissue. Astaxanthin dissolved in olive oil was given orally to the renal ischemia+astaxanthin group for 7 days before inducing renal ischemia. Caspase-(3, 8, 9), GSH, SOD, Total Thiol, TNF-α, IL-6, 8-OHdG were evaluated in each group.

Results: Renal IRI was verified by analysing the pathological changes of renal tissues and the renal functions after renal reperfusion. Much less renal tubular damage was determined in the IRI+ASX group in comparison to the IRI group. Caspase-8, -9 and -3 immunoreactivity was observed to be minimal in the control group. Apoptosis was observed to be significantly reduced in the IRI + ASX group with respect to the IRI group and close to the level of the control group (p <0.05). Caspase-3 levels of tissue samples were significantly increased in the IRI group compared to the other groups, but significantly lower in the IRI+ASX group with respect to the IRI group (p<0.05). The TOS and OSI levels, indicating increased oxidative stress, were significantly lower in the IRI+ASX group with respect to the IRI group (p <0.001), but still higher than the control group (p <0.001). In addition to GSH, SOD and Total Thiol levels, TAS levels were also significantly higher in the IRI + ASX group in comparison to the IRI group (p <0.05). TNF-α, IL-6, lipid hydroperoxide, AOPP and 8-OHdG levels were lower in the IRI+ASX group than the IRI group (p <0.001). MPO, IL-6, TNF-α levels, representing the parameters indicating neutrophil infiltration and inflammation of the renal tissues, significantly increased in the IRI group with respect to the other groups (p <0.005).

Conclusion: When all the data obtained in our study were evaluated, ASX was determined to prevent renal damage due to renovascular occlusion to a great extent, through complex mechanisms involving antioxidant, anti-inflammatory and antiapoptotic effects. Biochemical, histological and oxidative stress parameters were improved due to ASX.