Acute normovolemic hemodilution can aggravate neurological injury after spinal cord ischemia in rats

Hypervolemia suppresses dilutional anaemic injury in a rat model of haemodilution

Background and Objectives

Haemodilution leads to complications in clinical practice. It is exactly unknown whether this damage is caused by the fluid or by the stretching of the vascular bed. We aimed to compare two different haemodilution techniques at the same anaemic level.

Methods

Normovolemic or hypervolemic haemodilution was performed on twelve adult male Wistar rats. In the normovolemic procedure, blood was withdrawn and instantaneously administered with similar amounts of 6% hydroxyethyl starch (HES 130/0.4). Fluid was administered without withdrawing blood in the hypervolemic procedure. In both models, a 25% haematocrit level was targeted and kept at this level for 90 min to deepen the anaemia effect. Besides haemodynamics measurement, renal function (creatinine, blood urea nitrogen) and injury (tissue norepinephrine, malondialdehyde) were evaluated. Also, systemic hypoxia (lactate), oxidative stress (malondialdehyde, ischaemia-modified albumin), inflammation (tumour necrosis factor-alpha [TNF-α]), osmotic stress, adrenal stress (norepinephrine, epinephrine), and vascular stretching (atrial natriuretic peptide [ANP]) were assessed.

Results

Arterial pressure in the normovolemic group was lower than in the hypervolemic group. Serum creatinine, blood urea nitrogen, and lactate levels were higher in the normovolemic group. Tissue norepinephrine and malondialdehyde levels were higher in the normovolemic group. Serum ANP, malondialdehyde, ischaemia-modified albumin, free haemoglobin, syndecan-1, and TNF-α were higher in both groups compared to respective baseline.

Conclusions

Normovolemic haemodilution may lead to hypoxic kidney injury. The hypervolemic state may be advantageous if fluid is to be administered. Thus, the effect of the fluid itself can be relatively masked.

Protective effect of lutein on spinal cord ischemia-reperfusion injury in rats

OBJECTIVES

Paraplegia is deterioration in motor or sensory function of the lower limbs that can occur after modification of a thoracoabdominal aortic aneurysm. The purpose of this survey was to determine the protective action of lutein on spinal cord ischemia-reperfusion (I-R) damage.

MATERIALS AND METHODS

Thirty-five male rats were distributed into five groups: intact, sham, dimethyl sulfoxide (I-R+DMSO), low dose lutein (I-R+0.2 mg/kg lutein), and high dose lutein (I-R + 0.4 mg/kg lutein). Thirty minutes before surgery, a single dose lutein or DMSO was administered to rats of experimental groups. Next, the abdominal aorta was clamped exactly under the left renal artery and proximal to the abdominal aortic bifurcation for 60 min. All animals were evaluated by neurological function and histological and biochemical examinations at 72 hr after I-R.

RESULTS

The mean motor deficit index (MDI) scores in lutein groups were lower compared with the DMSO group (P<0.001). Plasma level of malondialdehyde in lutein groups decreased compared with the DMSO group (P<0.05). Plasma level of total antioxidative capacity was increased in the high lutein group compared with low dose lutein and sham groups (P<0.05). Mean number of normal motor neurons in lutein groups was greater compared with the DMSO group (P<0.001). There was a significant negative correlation between MDI scores and the number of normal neurons (r= -0.764, P<0.001).

CONCLUSION

Findings of the present study demonstrate that lutein may support spinal cord neurons from I-R damage.

Protective effect of aqueous spinach (Spinacia oleracea L.) extract on spinal cord ischemia-reperfusion injury in rats

Operation on the thoraco-abdominal aorta may lead to paraplegia or paraparesis is after spinal ischemia/reperfusion (I/R) injury. In this study, we investigated the protective effect of the spinach extract on spinal cord I/R injury. Thirty-five male Sprague-Dawley rats were divided into five groups: Intact, sham surgery, normal saline (NS), low dose spinach extract (20 mg kg^-1), high dose spinach extract (50 mg kg^-1). Neurological function, biochemical and histological evaluations were performed in 72 hr after ischemia. The mean motor deficit index scores of the spinach extract groups were significantly lower than in the NS group at 72hr after spinal cord ischemia. In addition, Spinach extract groups significantly increased plasma level of total antioxidative capacity and decreased the plasma level of malondialdehyde than the NS group. The spinach extract groups displayed a significantly large number of normal motor neurons compared with the NS group. In conclusion, the present study showed that the spinach extract may preserve more neurons in a rat model of spinal cord I/R injury.