Protection of ischaemic-reperfused rat heart by dimethylamiloride is associated with inhibition of mitochondrial permeability transition

Protective effects of co-administration of gallic Acid and cyclosporine on rat myocardial morphology against ischemia/reperfusion

BACKGROUND

Irreversible myocardial ischemic injury begins 20 minutes after the onset of coronary occlusion. Then the infarcted cells show signs of necrosis and death.

OBJECTIVES

This study investigated the effects of co-administration of Gallic acid (antioxidant) with cyclosporine (mitochondrial permeability transition pore [mPTP] inhibitor) on myocardial morphology of rats during ischemia and reperfusion.

MATERIALS AND METHODS

Fifty-four male Wistar rats (250-300 g), were randomly divided into 9 groups: sham, control (Ca received saline, 1 mL/kg, Cb: perfused with cyclosporine CsA 0.2 µM), 3 groups pretreated with Gallic acid in saline (G1a:7.5, G2a:15, and G3a: 30 mg/kg/day, and gavage daily for 10 days, n = 6), and the other three groups were pretreated with Gallic acid then perfused using CsA, (G1b:7.5, G2b:15, and G3b: 30 mg/kg/day) at the first 13 minutes of reperfusion period. After 10 days pretreatment, the rat hearts were isolated and transferred to Langendorff apparatus and exposed to 30 minutes ischemia following 60 minutes reperfusion. Afterward, the hearts were preserved in 10% formalin for histological studies at the end of the experiment. Finally, hematoxylin and eosin and Masson's trichrome staining techniques were used for evaluating the changes in myocardial architecture, degradation of myofibers, and collagen integrity. The differences were analyzed using Pearson test.

RESULTS

Cell degenerative changes, pyknotic nuclei, contraction bands, edema, and loosening of collagen in between muscle fibers were observed during ischemia-reperfusion. Myocardial architecture and cellular morphology were recovered in co-administration groups, especially in (Gallic acid 15 mg/kg + CsA, P < 0.001).

CONCLUSIONS

The results suggest the important role of the antioxidant system potentiation in the prevention of myocardial damage.

Crush injuries and crush syndrome - a review. Part 2: the local injury

Crush injuries can occur in considerable numbers following natural disasters or acts of war and terrorism. They can also occur sporadically after industrial accidents or following periods of unconsciousness from drug intoxication, anaesthesia, trauma or cerebral events. A common pathophysiological pathway has been elucidated over the last century describing traumatic rhabdomyolysis leading to myoglobinuric acute renal failure and a systemic ‘crush syndrome’ affecting many organ systems. If left unrecognised or untreated then mortality rates are high. If treatment is commenced early and the systemic effects are minimised then patients are often faced with significant morbidity from the crushed limbs themselves. We have performed a thorough review of the English language literature from 1940—2009 investigating crush injuries and crush syndrome and present a comprehensive, two-part summary. Part 1: The systemic injury, we concentrate on the systemic crush syndrome. We determine the pathophysiology, clinical and prognostic indicators and treatment options such as forced alkaline diuresis, mannitol therapy, dialysis and haemofiltration. We discuss more controversial treatment options such as allopurinol, potassium binders, calcium therapy and other diuretics. We also discuss the specific management issues of the secondary ‘renal disaster’ that can occur following earthquakes and other mass disasters. Part 2: The local injury, we look in more detail at the pathophysiology of skeletal muscle damage following crush injuries and discuss how to minimise morbidity by salvaging limb function. In particular we discuss the controversies surrounding fasciotomy of crushed limbs and compare surgical management with conservative techniques such as mannitol therapy, hyperbaric oxygen therapy, topical negative pressure therapy and a novel topical treatment called gastric pentadecapeptide BPC 157.