The effects of L-carnitine on spinal cord ischemia/reperfusion injury in rabbits.

BACKGROUND: Paraplegia after distal aortic aneurysm repair remains a persistent clinical problem. We hypothesized that the tolerance of the spinal cord to an ischemic period could be improved with hypothermic Ringer's Lactate containing L-Carnitine. MATERIALS AND METHODS: Twenty-eight New Zealand white rabbits were used as spinal cord ischemia models. We separated rabbits into four equal groups and clamped each animal's abdominal aorta distal to the left renal artery. We occluded the aortas above the iliac bifurcation for 30 minutes. In group I, the infrarenal aorta was clamped without infusing any solution. In group II, Ringer's Lactate solution was infused at + 25degrees C for 3 minutes at a rate of 5 ml/min into the isolated aortic segments immediately after cross-clamping and the last 3 minutes of ischemia. In group III, Ringer's Lactate solution at +3 degrees C was given in the same method as that of group II. In group IV, Ringer's Lactate solution at +3 degrees C plus 100 mg/kg of L-carnitine was infused using the same technique. We assessed the neurological status of the hind limbs 24 and 48 hours after operation according to Tarlov's criteria. All animals were sacrificed and spinal cords were harvested for histological analyses. RESULTS: The neurological status in groups III and IV was significantly superior to that of groups I and II. All the animals in group I had complete hind-limb paraplegia. Complete hind-limb paraplegia occurred in 5 rabbits in group II. Two of the 7 animals in group III had spastic paraplegia, and none at all in group IV. Histological analysis of the cross-clamped segments of the rabbits with paraplegia in group I, II and III revealed changes consistent with ischemic injury, while findings were normal for the normal animals in group III and IV. CONCLUSIONS: In this model, the infusion of hypothermic Ringer's Lactate contained L-carnitine provided sufficient spinal cord protection against ischemia. Clinically, this may be a useful adjunct for prevention of paraplegia during surgery of the descending aorta.

An intraaortic solution trial to prevent spinal cord injury in a rabbit model.

OBJECTIVES: to evaluate the effectiveness of an intraaortic delivered solution on preventing spinal cord injury. DESIGN: forty rabbits were allocated into five equal groups. MATERIALS AND METHODS: one clamp was placed just distal to the left renal artery, and another was placed just above the iliac bifurcation for 40 min. Group 1 was not infused (control group). Through a 24G vascular catheter inserted into the isolated aortic segment, 20 ml of LR solution at room temperature (Group 2) 20 ml of LR solution at 3 degrees C (Group 3), and 20 ml of LR solution at 3 degrees C containing 30 mg/kg of methylprednisolone (Group 4) were infused over 3 min. In Group 5, 10 mg/kg of vitamins E and C were delivered two days before the experiment, and 20 ml of LR solution at 3 degrees C containing 30 mg/kg of methylprednisolone, and 10 mg/kg of vitamins E and C was infused at the operation. Postoperative spinal cord function was assessed using Tarlov's criteria. RESULTS: the neurologic status of Groups 3, 4, and 5 was significantly superior to that of Groups 1 and 2. No paraplegia was observed in Groups 4 and 5. Spastic paraplegia occurred in all rabbits of Groups 1 and 2, and in 20% of Group 3. In the electron microscopic evaluation of spinal cord specimens, normal histologic structure was observed in Groups 4 and 5, whereas, some derangements were observed in all others. CONCLUSIONS: intraaortic infusion of a hypothermic blended solution containing methylprednisolone, vitamins C and E provided best protection against postischaemic spinal cord dysfunction.

Histological and biochemical effects of cigarette smoke on lungs.

In this study, rats were made to inhale cigarette smoke in a specifically prepared container for different periods. The lung tissue samples of the subjects were examined by light microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Malonaldehyde, one of the free oxygen radicals was determined in lungs and plasma. The catalase activity level of erythrocyte and arginase levels were determined. Three groups were formed. The rats in the Ist and IInd groups were made to inhale cigarette smoke for 30 and 60 minutes a day for a total period of 3 months. Control group, the rats in the IIIrd group (controls) were made to inhale clean air during the same periods. An increase in the number of macrophages was observed in the pulmonary tissue of the exposed groups. Especially in the group that inhaled the smoke for long periods, the number of macrophages and the inclusion bodies contained in them increased. These differences could easily be observed in TEM studies. In the light microscopy and SEM observations, it arouse attention that the alveolar macrophages occurred as sets and their activation increased. Depending on the length of the exposure to cigarette smoke, an increase in the number of macrophages was observed. Statistically significant increases were determined in the malonaldehyde levels of pulmonary tissue and plasma when compared to the control group. Besides significant increases were found in the catalase activity levels of erythrocytes in the experimental groups.

Case report: a rare congenital esophageal malformation on double esophagus in the rat.

A double esophagus was coincidently observed in one male rat among a group of Wistar adult rats used for histological studies. This is apparently the first case reported in the rat and other animals.

The effect of xylene inhalation on the rat liver.

In this study, 11,284 mg/m3 (2600 ppm) of xylene was administered for 8 hours a day to pregnant rats by means of inhalation, starting from the sixth day of their pregnancies. Furthermore, while a group of non-pregnant rats inhaled the same amount of xylene during the same period, the control group inhaled clean air. Consequently, in addition to the embryotoxic effects of xylene, the effects on the various tissues of the mothers and their litters were observed light and electron microscopes. No external anomalies were observed in any of the rats born at the end of the 21st day, and there were no macroscopic defects in their organs either. While following xylene inhalation no structural defects in the kidney and pancreas was found, expansions in the smooth endoplasmic reticulum of the liver tissues, increases in the lysosomes, and defective mitochondrion structures were found in the pregnant and non-pregnant rats. It was noticed that xylene in particular caused structural defects in the liver of the fetus. Compared to the control groups, increases were observed in the activities of the AST, ALT, ALP, and Arginase enzymes in the liver.