Arterial Blood Supply to the Spinal Cord in Animal Models of Spinal Cord Injury. A Review.

Animal models are used to examine the results of experimental spinal cord injury. Alterations in spinal cord blood supply caused by complex spinal cord injuries contribute significantly to the diversity and severity of the spinal cord damage, particularly ischemic changes. However, the literature has not completely clarified our knowledge of anatomy of the complex three-dimensional arterial system of the spinal cord in experimental animals, which can impede the translation of experimental results to human clinical applications. As the literary sources dealing with the spinal cord arterial blood supply in experimental animals are limited and scattered, the authors performed a review of the anatomy of the arterial blood supply to the spinal cord in several experimental animals, including pigs, dogs, cats, rabbits, guinea pigs, rats, and mice and created a coherent format discussing the interspecies differences. This provides researchers with a valuable tool for the selection of the most suitable animal model for their experiments in the study of spinal cord ischemia and provides clinicians with a basis for the appropriate translation of research work to their clinical applications. Anat Rec, 300:2091-2106, 2017. © 2017 Wiley Periodicals, Inc.

Arrangement of Renal Arteries in Guinea Pig.

The aim of this study was to describe origin, localization, and variations of renal arteries in guinea pig. The study was carried out on 26 adult guinea pigs. We prepared corrosion casts of the guinea pig arterial system. Batson's corrosion casting kit no. 17 was used as the casting medium. In 57.7% of specimens, a. renalis dextra was present as a single vessel with different level of its origin from aorta abdominalis. In 38.5% of specimens, two aa. renales dextrae were present with variable origin and arrangement. The presence of three aa. renales dextrae we found in one specimen. In 76.9% of specimens, a. renalis sinistra was present as a single vessel with different level of its origin from aorta abdominalis and variable arrangement. In 23.1% of specimens, we found two aa. renales sinistrae with variable origin and arrangement. The anatomical knowledge of the renal arteries, and its variations are of extreme importance for the surgeon that approaches the retroperitoneal region in several experiments, results of which are extrapolated in human. This is the first work dealing with the description of renal arteries arrangement in guinea pig. Anat Rec, 300:556-559, 2017. © 2016 Wiley Periodicals, Inc.

Blood supply to the thoracolumbar spinal cord in the laboratory mouse using corrosion and dissection techniques.

Mice are used frequently as experimental models in the study of ischemic spinal cord injury. The aim of the present study was to describe the arterial blood supply to the thoracolumbar spinal cord in the mouse. The study was carried out on 20 adult mice using the corrosion and dissection technique. Dorsal intercostal arteries were found as branches of the thoracic aorta: as 7 pairs in 80% of cases, as 8 pairs in 15% of cases and as 9 pairs in 5% of cases. The paired lumbar arteries arising from the abdominal aorta were present as 5 pairs in all cases. Along the entire thoracic and lumbar spinal regions, we observed left-sided branches entering the ventral spinal artery in 64.2% and right-sided branches in 35.8% of cases. Along the entire thoracic and lumbar spinal regions, the branches entering the dorsal spinal arteries were left-sided in 60.8% of cases and right-sided in 39.2% of cases. We found some variations in the site of origin of the artery of Adamkiewicz and in the number of dorsal spinal arteries. Documenting the anatomical variations in spinal cord blood supply in the laboratory mouse will aid the planning of future experimental studies and in determining the clinical relevance of such studies.

A preliminary trial of the sedation induced by intranasal administration of midazolam alone or in combination with dexmedetomidine and reversal by atipamezole for a short-term immobilization in pigeons.

OBJECTIVE: To assess the sedative and immobilization effect of intranasal administration (INS) of midazolam (MID) without or with INS dexmedetomidine (DXM), and some physiological changes induced by the drugs. The ability of INS atipamezole to reverse the DXM component was also assessed. STUDY DESIGN: Prospective 'blinded' experimental study. ANIMALS: In total, 15 pigeons. METHODS: Pigeons were sedated by INS MID alone at a dose of 5 mg kg(-1) (group MID, n = 6) or in combination with INS DXM at a dose 80 µg kg(-1) (group MID-DXM, n = 6). Measurements were made of heart rate (HR), respiratory rate (fR ) and cloacal temperature (CT). The degree of sedation was assessed at 15 minutes prior to, immediately after, and at intervals until 100 minutes after drug administrations. Following MID-DXM, INS atipamezole (250 µg kg(-1) ) was administered and the same indices measured 5 and 10 minutes later. RESULTS: MID had no effect on HR and fR , and although CT decreased, it remained within physiological range. MID-DXM caused significant falls in HR, fR and CT that persisted until the end of sedation. Atipamezole antagonized sedation and cardiorespiratory side effects of MID-DXM within 10 minutes of application. In addition, for MID compared to MID-DXM, the lowest sedation scores [10 (7-14) and 10.5 (5-14) versus 2 (1-4) and 2 (1-5)] were achieved in the 10th and 20th minute versus the 20th and 30th minute of the sedation, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: MID alone, given INS had minimal side effects on vital functions but caused inadequate immobilization of pigeons for restraint in dorsal recumbency. MID-DXM caused an effective degree of immobilization from 20 to 30 minutes after administration, at which time birds tolerated postural changes without resistance. Atipamezole antagonized both side effects and sedation, but complete recovery had not occurred within 10 minutes after its application.

Anatomical study of blood supply to the cervical spinal cord in the guinea pig.

The aim of this study was to describe the arterial arrangement of the cervical spinal cord in the guinea pig. The study was carried out on 20 adult English self guinea pigs using corrosion and dissection technique. Batson's corrosion casting kit no. 17(©) was used as a casting medium. The origin of the ventral spinal artery from the left vertebral artery was found on average in 35% of the cases and from the right vertebral artery on average in 40% of the cases. The ventral spinal artery with origin from the anastomosis of two medial branches was found on average in 25% of the cases. The presence of ventral radicular branches of rami spinales entering the ventral spinal artery in the cervical region was observed in 42% of the cases on the right side and in 58% of the cases on the left side. The presence of dorsal radicular branches of rami spinales that reached the spinal cord was observed in 63% of the cases on the left side and in 37% of the cases on the right side. The number of radicular branches supplying the spinal cord is greater in guinea pig than in humans.

Morphometric alterations, steatosis, fibrosis and active caspase-3 detection in carbamate bendiocarb treated rabbit liver.

Increasing use of pesticides all over the world makes it necessary to reveal the toxic risk in populations of nontargeted organisms. Bendiocarb is one of the 12 insecticides recommended by the World Health Organization for use in malaria control in Africa, and is used against a variety of insects. The liver has an important role in its process of detoxication and excretion. In our experiment 56 adult rabbits of breed HY+, 28 males and 28 females were used. Animals were divided into groups (control, days 10, 20, 30 of bendiocarb administration). The presence of many binucleated hepatocytes, the highest number of liver cells and their decreased size at 10 day after bendiocarb administration was observed as an evidence of the hepatic regeneration. After the long-term treatment pronounced changes were presented such as vacuolization and dilatation of hepatocytes, dilatation of sinusoids between hepatocytes, and focal infiltration of inflammatory cells. Numerous cells with caspase-3 activity were present throughout the organ, most commonly around the portal tract and close to the central vein. Short and long-term bendiocarb treatment showed the central vein thickened rim with increased deposition of collagen, spreading of collagen fibers into the perisinusoidal, and pericellular space surrounding the central veins, and septal fibrosis extended from the portal tract. Subsequently, presence of the lipid vacuoles both in the liver parenchyma and inner of the hepatocytes were observed. These results suggest that bendiocarb treatment leads to increased cell death, liver perisinusoidal fibrosis, and steatosis, especially during the long-term administration.

Anatomical study of the arterial blood supply to the thoracolumbar spinal cord in guinea pig.

Guinea pigs are frequently used as experimental models in studies of ischemic spinal cord injury. The aim of this study was to describe the arterial blood supply to the thoracolumbar spinal cord in 20 adult English self guinea pigs using the corrosion and dissection techniques. The dorsal intercostal arteries arising from the dorsal surface of the thoracic aorta were found as follows: in eight pairs in 70% of cases, in seven pairs in 20% of cases and in nine pairs in 10% of cases. Paired lumbar arteries were present as seven pairs in all the cases. The occurrence of the ventral and dorsal branches of the spinal rami observed in the thoracic and lumbar region was higher on the left than on the right. The artery of Adamkiewicz was present in 60% of cases as a single vessel and in 40% of cases as a double vessel. On the dorsal surface of the spinal cord, we found two dorsal spinal arteries in 60% of cases and three in 40% of cases. The presence of the artery of Adamkiewicz and nearly regular segmental blood supplying the thoracolumbar part of the spinal cord in all our studied animals is the reason for using guinea pigs as a simple model of ischemic damage to the thoracolumbar part of the spinal cord.

The Anatomical Correlation between the Internal Venous Vertebral System and the Cranial Venae Cavae in Rabbit.

The aim of this study was to describe the possible variations in the connection between the internal venous vertebral system and the cranial vena cava in rabbit using corrosion technique. The study was carried out on 40 adult New Zealand white rabbits. The venous system was injected by using Batson's corrosion casting kit number 17. We found the connection between the internal venous vertebral system and the cranial vena cava by means of the vertebral veins and the right azygos vein. The vertebral vein was present as independent tributary in 36 cases (90%). In the rest of the cases, it was found as being double, being triple, or forming a common trunk with other veins. The azygos vein was present as independent tributary of the cranial vena cava in 39 cases (97.5%). We found also a common trunk formed by the junction of the deep cervical vein, the right vertebral vein, and the azygos vein in one case (2.5%). The azygos vein received 6, 7, 8, or 9 pairs of dorsal intercostal veins. Documenting the anatomical variations in the rabbit will aid in the planning of future experimental studies and determining the clinical relevance on such studies.

Arterial arrangement of the cervical spinal cord in rabbit.

The aim of this study was to describe the arterial arrangement of the cervical spinal cord in rabbit because it has been used widely to examine the pathophysiology of spinal cord injury. The study was carried out on 20 adult New Zealand White rabbits. We prepared corrosion casts of the arterial system of the cervical spinal cord. Batson's corrosion casting kit no. 17 was used as a casting medium. The origin of the ventral spinal artery from the right vertebral artery was found on average in 40 % of cases. The origin from the left vertebral artery was found on average in 35 % of cases. The ventral spinal artery raised from the anastomosis of two ventral spinal arteries on average in 25 % of cases. The presence of spinal arteries entering the ventral spinal artery in the cervical region was observed in 46.2 % of cases on the right side and in 53.8 % of cases on the left side. On the dorsal surface we found two irregular dorsal spinal arteries receiving dorsal branches of spinal arteries or they were absent. Until the cervical spinal cord arterial arrangement in species of laboratory animals is described in detail, it will be very difficult to determine the appropriate species for experiments in this field. Variations in arterial arrangement can produce biased or erroneous results in studies.

Changes of the immunological and haematological parameters in rabbits after bendiocarbamate application.

The effect of bendiocarbamate application (5 mg/kg b.w.) on the haematological and immunological parameters in rabbits was evaluated. Total leukocyte cell count, erythrocyte cell count, differential cell count were determined during the period of three months of bendiocarbamate application and compared with those in healthy animals. The immunotoxic effect was evaluated by the test of ingestion ability of phagocytes (phagocytic activity and index of phagocytic activity) and proliferation activity of lymphocytes after mitogen stimulation. The significant decrease of total leukocytes, lymphocytosis and neutropaenia were found after bendiocarbamate application. The functional activities of phagocytes (expressed as phagocytic activity) and lymphocytes (proliferative activity) were significantly suppressed in rabbits treated with bendiocarbamate compared with those in control groups and values before the experiment.

Chick development and high dose of bendiocarb.

Developmental data of carbamate pesticides are scarce although they generally possess low toxicity for vertebrates. The aim of the study was to investigate the toxicity of bendiocarb to liver and central nervous system of chick embryos. Bendiocarb (1600 µg/egg) was administered to the embryo through membrana papyracea on embryonic day 3 and 10. In the liver and central nervous system we observed no macroscopic or microscopic changes. These organs were also investigated for caspase activity in regard to application of bendiocarb and no differences in the caspase immunopositivity were observed in comparison with the control. The embryolethality after bendiocarb respective dose was high (94 %) on the embryonic day 3, though following results indicated no toxicity to investigated organs and no increase in the number of apoptotic cells in survived chick embryos on both the early (day 3 of incubation) and the later (day 10 of incubation) developmental stage.

Alterations in the rabbit lymphoid tissue after bendiocarb administration.

Various pesticides have immuno-suppressive effects, and thus the organisms become responsive to viral, bacterial and parasitic diseases and neoplasm. The aim of the study was to observe the structure of the small intestine (height of enterocytes and crypts), mucosal lymphoid tissue (Payer's patches, lymphocytes in lamina propria) and a lymph node after administration of bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-yl-methylcarbamate) on days 3, 10, 20, 30 and 60 of the experiment. The height of the observed enterocytes showed an increasing tendency. On days 20, 30 and 60 we also observed an increase in diameter of crypts located in intestinal epithelium. The number of cells in lamina propria mucosae was significantly reduced on days 20 and 30 after administration of bendiocarb. Observations of the lymph node showed that on days 10 and 20 there was a significant increase in relative volume of medulla at the expense of the relative volume of the cortex and a decrease in the number of lymphocytes. However, we recorded an increase in diameter of lymphocytes. The intracellular parasite Toxoplasma gondii (T. gondii) belongs to the most common pathogenic parasites in the world and it can cause serious health complications in pregnant and immunodeficient individuals. DNA isolation, standard polymerase chain reaction (PCR) and visualization in a 2.5 % agarose gel, the presence of DNA T. gondii was detected in no examined rabbit brain samples. Using real time PCR T. gondii DNA was detected and quantified in the three rabbit brain samples (10 %).

Effect of bendiocarb on development of the chick embryo.

Agrochemicals, including pesticides, are being used in increasing amounts in agriculture and are therefore potential environmental contaminants which may affect a variety of biological systems. The pesticide residues directly affect the embryos, disturbing their normal development and causing pathophysiological and morphological changes. We have observed embryotoxicity of cholinesterase inhibitor bendiocarb in the chick embryo. The pesticide dissolved in 10% acetone in water for injection was applied in a volume of 200 microl over the embryo through membrana papyracea at embryonic days (ED) 2, 3, 4, 5 and 10. The toxicity of bendiocarb was rather low, and lethal dose (LD(50)) decreased with advancing development from 0.97 mg per egg at ED 2 to 28.6 mg on ED 5. The malformations in surviving embryos were observed rarely (<2%) and occurred in both control and experimental groups. In the treatment at ED 5 and 10 there was a statistically significant reduction in body weight, but the maximum difference from controls was below 14%. In treated chick embryos on ED 3 and 4 was observed a small but not significant increase in number of dead cells using supravital staining. We conclude that bendiocarb possesses no significant toxicity in the avian embryo. Our analysis of bendiocarb embryotoxic potential in the chick embryo supports the earlier observations in other animal models, testifying to the relative safety of bendiocarb for the embryo or fetus.

The importance of the origin of vertebral arteries in cerebral ischemia in the rabbit.

The aim of this study was to verify whether experimentally induced total cerebral ischemia in rabbits actually corresponds to total ischemia on the basis of the origin of certain vessels. We observed morphological variations in the origin and course of the arteria vertebralis as one of the vessels supplying the brain with blood. Investigations were carried out on 50 adult New Zealand rabbits. We prepared corrosion casts of the arterial system using Duracryl Dental. We found that in 86% of cases (43 animals) the arteria vertebralis sinistra originated directly from the arteria subclavia sinistra, in 10% of cases (5 animals) it originated from the arcus aortae as an independent branch, and in 4% of cases (2 animals) it arose from the arcus aortae as a common trunk with the arteria scapularis descendens. The arteria vertebralis dextra originated from the arteria subclavia dextra in 98% (49 animals) of cases. In one case we observed two arteria vertebralis dextra with two different origins. Bilateral variability in the origin of the arteria vertebralis was observed in 12% of cases (6 animals). Our results show that ligation of the truncus brachiocephalicus and of the arteria subclavia sinistra do not necessarily cause total cerebral ischemia.