Evaluation of the effects of rosmarinic acid on red blood cell deformability, morphology, and nitric oxide in rat lower limb skeletal muscle ischemia-reperfusion injury.

Background: Erythrocyte deformability, the ability of red blood cells to bend and twist as they pass through capillaries, is es-sential for tissue perfusion. This study investigates the effects and underlying mechanisms of rosmarinic acid treatment on erythrocyte deformability in rats subjected to lower limb ischemia-reperfusion injury.

Methods: The study was conducted on Wistar albino rats weighing 400-450 g. The rats were randomly divided into five groups: the control group with no treatment (C), the group receiving only the solvent dimethyl sulfoxide (DMSO), the ischemia-reperfusion group (IR) subjected to 90 minutes of ischemia followed by 90 minutes of reperfusion in the femoral artery of the lower limb, the rosmarinic acid control group (RA-C) to assess the effects of rosmarinic acid alone, and the group (IR+RA) in which rosmarinic acid was administered intraperitoneally one hour before the ischemia-reperfusion procedure. At the end of the experiment, intracardiac blood samples were collected. Analyses included May-Grünwald-Giemsa (MGG) staining, measurement of endothelial nitric oxide synthase (eNOS), erythrocyte deformability indexes, malondialdehyde (MDA), and superoxide dismutase (SOD) levels.

Results: Significant findings were observed in the study. Erythrocyte deformability was statistically significantly improved in the group that received rosmarinic acid prior to ischemia-reperfusion compared to the group that underwent ischemia-reperfusion alone. Morphological changes of erythrocytes were also significantly better in the IR+RA group than in the IR group. Immunohistochemical analysis of eNOS staining revealed that eNOS activity was higher in the IR group compared to the IR+RA group. Malondialdehyde (MDA) levels were significantly elevated in the IR group compared to all other groups. Analysis of superoxide dismutase levels showed that the SOD levels in the IR+RA group were significantly higher than those in the other groups.

Conclusion: Our findings indicate that rosmarinic acid treatment administered prior to ischemia provides protective effects against erythrocyte deformation and morphological deterioration. It is suggested that the improvement in deformability may be mediated by increased SOD activity, which reduces reactive oxygen anions, by-products of nitric oxide (NO) production, thereby exerting an antioxidant effect and enhancing the beneficial actions of NO.