Protective Effects of Bosentan via Endothelin Receptor Antagonism in Experimental Ischemia-Reperfusion Injury in the Lower Limb of Rats.

OBJECTIVE

This study aimed to evaluate the protective effects of bosentan, a dual endothelin receptor antagonist, against skeletal muscle ischemia-reperfusion injury (IRI) in rats.

METHODS

A total of 24 male Wistar Albino rats were divided into four groups: control (C, n=6), bosentan-treated (B, n=6), ischemia-reperfusion (IR, n=6), and bosentan plus ischemia-reperfusion (B+IR, n=6). Bosentan (10 mg/kg) was administered 30 minutes prior to reperfusion. In the IR and B+IR groups, ischemia was induced using vascular bulldog clamps for 45 minutes, followed by 120 minutes of reperfusion.

RESULTS

Histological and biochemical assessments revealed significant differences among the groups. The disorganization and degeneration scores of the muscle cells in the B+IR group were significantly lower than those in the IR group (P = 0.001). The degree of interstitial edema in the IR group was markedly more severe than in the C and B groups (all P < 0.001), while the interstitial edema score in the B+IR group was significantly lower than that in the IR group (P < 0.001). The total muscle injury scores were markedly reduced in the B+IR group compared to the IR group (P < 0.001). Biochemically, TAS levels were significantly higher in the B+IR group compared to the IR group (1.03 ± 0.18 vs 0.59 ± 0.10 mmol/L, P = 0.016). Conversely, TOS (1.97 ± 0.39 vs 2.86 ± 0.43 IU/mg, P < 0.001) and OSI levels (P < 0.001) were significantly lower in the B+IR group. Additionally, paraoxonase (PON-1) enzyme activity was significantly reduced in the B+IR group compared to the IR group (P < 0.001). These findings suggest that bosentan exerts its protective effects by antagonizing endothelin-1 receptors, thereby mitigating vasoconstriction, oxidative stress, and inflammation. The observed reductions in muscle cell disorganization, interstitial edema, hemorrhage, neutrophil infiltration and oxidative stress markers underscore bosentan's potential as a therapeutic agent for managing ischemia-reperfusion injury.

CONCLUSION

Bosentan demonstrates significant protective effects against skeletal muscle IRI by reducing oxidative stress and inflammation through endothelin receptor antagonism. These findings underscore bosentan's potential as a therapeutic agent for mitigating ischemia-reperfusion injury in vascular surgeries and managing critical limb ischemia in clinical settings. Further research is warranted to explore the long-term effects of bosentan on muscle recovery and systemic health following ischemia-reperfusion injury.