A histomorphometric study on the hepatoprotective effects of a green rooibos extract in a diet-induced obese rat model.

Obesity, type two diabetes mellitus and insulin resistance are associated with increased oxidative stress and inflammation. Unfermented green rooibos is an aspalathin rich variant of traditional fermented rooibos (Aspalathus linearis) and has a high polyphenol content. The present study aimed to determine the histologically observable effects of a commercially produced, aspalathin-rich green rooibos extract, Afriplex GRT™ (GRE) in a diet-induced obese rat model. Male Wistar rats (N = 28) were randomly assigned to four study groups (n = 7): control (C), green rooibos (GRT), high-fat diet (HFD) and experimental (HFD-GRT) group. Body mass was determined prior to euthanasia and liver mass was determined after death. The left lateral lobe of the liver was processed to wax and stained using haematoxylin and eosin (H & E), Masson's trichrome stain, Gordons and Sweet's reticulin impregnation and periodic acid-Schiff stain. Frozen liver tissue sections were used for Oil red O staining. Morphometric quantification of steatosis, semiquantitative pathology grading and scoring were performed and verified by a veterinary histopathologist. A significant increase in body and liver mass was observed in the HFD groups while co-treatment with green rooibos significantly reduced both. The volume and area of steatosis were significantly increased in the HFD groups while the area of steatosis significantly reduced with green rooibos co-treatment. The percentage, location and type of steatosis as well as presence of inflammation and hepatocellular injury were reduced in the HFD group co-treated with GRE. These findings suggest that a GRE has potential as an anti-steatotic, anti-inflammatory and weight reducing agent in vivo.

Hind foot drumming: morphological adaptations of the muscles and bones of the hind limb in three African mole-rat species.

Seismic signalling in the form of hind foot drumming plays an integral role in the communication of several species of African mole-rats (Bathyergidae). To produce these vibrational signals, alternating hind limbs strike the ground repetitively at high speeds by flexion and extension of the hip and knee. This descriptive study aimed to determine whether anatomical differences in hind limb osteology and/or musculature between drumming and non-drumming species of three Bathyergidae species could be detected. Formalin-fixed left and right hind limbs of 24 animals (N = 48) consisting of three species (n = 16 each) of two drumming species, Georychus capensis and Bathyergus suillus, and one non-drumming species, Cryptomys hottentotus natalensis, were dissected to determine the origins and insertions of individual muscles. After dissection, all soft tissue was removed by maceration. Hind limb bones, including the pelvis, were photographed, and the exact muscle origin and insertion points were electronically mapped onto the images using imaging software. On lateral view, the acetabular position was parallel to the sacrum in G. capensis, while being more ventral in position in the other two species. The shape of the femur head was spherical and the neck defined in all species. The distal shaft of the femur was gracile and the epicondyles were robust and prominent in the non-drumming C. h. natalensis compared with the drumming species. Shallow and relatively wide patellar grooves were observed in all three species. In the two drumming species, m. gracilis was single, whereas it was double in C. h. natalensis. In all three species, m. tensor fasciae latae was absent. The more dorsal positioning of the acetabulum in G. capensis may be needed to increase the stability of the spine and allow for more force to be exerted on the pelvis during drumming. It is unlikely that m. gracilis plays a role in drumming, as the singularity or doubling thereof is variable among rodents. It is additionally postulated that m. gluteus superficialis has taken the hip rotator role of m. tensor fasciae latae as it partially inserted onto the lateral fascia of the thigh. The more robust ilia, femoral shafts and tibiae observed in the two drumming species studied here are possible adaptations for hind foot drumming, as robust bones are able to withstand the additional biomechanical loading during drumming.

A histomorphometric study on the effects of antiretroviral therapy (ART) combined with a high-calorie diet (HCD) on aortic perivascular adipose tissue (PVAT).

Perivascular adipose tissue (PVAT), surrounding arteries is metabolically active. Obesity and antiretroviral therapy (ART) may cause pathophysiological conditions in the aortic wall and surrounding PVAT. The aim of the study was to determine the histological effects on the aortic wall, aortic PVAT adipocyte morphology and leptin staining intensity in obese rats treated with ART. Wistar rats (N=36) were divided into four groups; a lean control (C/ART-), ART control (C/ART+), high-calorie diet (HCD) untreated (HCD/ART-) and HCD and ART experimental (HCD/ART+). The aorta and surrounding PVAT were stained with haematoxylin and eosin (H&E) and anti-leptin antibodies for immunohistochemistry (IHC). The C/ART+ group had a thinner tunica media compared to the HCD/ART- group. The tunica adventitia was thicker in the ART groups (C/ART+ and HCD/ART+) compared to the lean control group. White adipocytes in the HCD/ART- group was larger in size compared to the other three groups. The high-calorie diet groups (HCD/ART- and HCD/ART+) had increased adipocyte sizes, for both brown and differentiating adipocytes, compared to the control groups (C/ART- and C/ART+). The unilocular and differentiating adipocytes in the C/ART+ group showed intense leptin staining. Unilocular and differentiating adipocytes in the HCD/ART- and HCD/ART+ groups showed weak to no leptin staining intensity. The present study indicated that ART and a HCD, separately and combined, altered both the tunica media and adventitia of the aortic wall, whereas the HCD alone caused adipocytes to increase in size. The leptin staining intensity suggested that ART alone may lead to increased leptin expression, whereas ART combined with a HCD may cause leptin deficiency. Changes seen with ART in a rat model suggest that aortic wall thickness and PVAT adipocyte morphology alterations should be considered by clinicians in obese individuals receiving ART.

The posterior intercostal vein: a thermoregulatory gateway to the internal vertebral venous plexus.

The internal vertebral venous plexus (IVVP) plays a putative role in thermoregulation of the spinal cord. Cold cutaneous venous blood may cool, while warm venous blood from muscles and brown fat areas may warm the spinal cord. The regulating mechanisms for both cooling and warming are still unknown. Warm venous blood mainly enters the IVVP via the intervertebral veins. In the thoracic area these veins are connected to the posterior intercostal veins. In this study, anatomical structures were investigated that might support the mechanisms by which warmed venous blood from the intercostal muscles and the recently described paravertebral patches of brown adipose tissue are able to drain into the vertebral venous plexus. Therefore, tissue samples from human cadavers (n = 21) containing the posterior intercostal vein and its connections to the IVVP and the azygos veins were removed and processed for histology. Serial sections revealed that the proximal parts of the posterior intercostal veins contained abundant smooth muscle fibers at their opening into the azygos vein. Furthermore, the walls of the proximal parts of the posterior intercostal veins contain plicae that allow the vessel to dilate, thereby allowing it to serve as a pressure chamber. It is suggested that a cold induced closure of the intercostal/azygos opening can result in retrograde blood flow from the proximal posterior intercostal vein towards the IVVP. This blood flow would be composed of warm blood from the paravertebral brown adipose tissue and blood containing metabolic heat from the muscles draining into the intercostal veins.

Possible thermoregulatory functions of the internal vertebral venous plexus in man and various other mammals: evidence from comparative anatomical studies.

Comparative anatomy was used to collect more evidence for a thermoregulatory function of the internal vertebral venous plexus (IVVP). The venous connections of the IVVP were studied and compared in various mammals in order to find evidence for the existence of climate related anatomical adaptations. Humans and vervet monkeys were chosen as representatives of mammals living in moderate climates, the IVVP of the dolphin was studied because this animal is always surrounded by cold water. The springbok was chosen as a representative of mammalian species living under very hot conditions. The present study was exclusively performed on post mortem material. After filling the venous system with latex the IVVP and its venous connections were dissected. It appeared that in the dolphin, veins from the trunk muscles were directly and exclusively connected to the IVVP in the absence of an azygos vein. In the vervet monkey and human specimens, veins originating in the muscles drained both into the caval veins and into the IVVP. In these mammals veins draining from brown fat areas were also connected to the IVVP. In the springbok, drainage of blood from the muscles was prevented to enter the IVVP by the presence of valves. In humans and vervet monkeys we found that the lumbar parts of the IVVP were connected to subcutaneous veins of the back. It was concluded that the anatomy of the IVVP and its connecting veins may serve to thermoregulate the spinal cord and that climate related anatomical adaptations were present in the species studied.

A morphological study of the vertebral venous plexus and its connections in the Cape dune mole-rat, Bathyergus suillus (Bathyergidae).

Bathyergus suillus are subterranean rodents found in the Western Cape of South Africa, where they inhabit sandy, humid burrows. Vertebral venous plexuses around the vertebral column have been implicated in aiding the maintenance of a constant central nervous system temperature via its connections with muscles and interscapular brown adipose tissue. The morphology of the vertebral venous plexuses and its connections in B.suillus were investigated. Frozen (n = 10) animals were defrosted; the venous system injected with latex and the vertebral venous plexuses, azygos- and intercostal veins dissected along the dorsal and ventral aspects of the vertebral column. Specimens (n = 4) were used for histological serial cross sections of the thoracic vertebrae. Veins drained from the interscapular brown adipose tissue to the external vertebral venous plexus, via a dorsal vein at the spinous process of T2 which might represent the "vein of Sulzer" described in rats. The intercostal veins cranial to the level of T8 drained directly into the ventral external vertebral venous plexus instead of into the azygos vein as seen in rats. The azygos vein was situated ventrally on the thoracic vertebral bodies in the median plane as opposed to most rodents that have a left sided azygos vein. The internal vertebral venous plexus consisted of two ventrolateraly placed longitudinal veins in the spinal epidural space. Veins from the forelimbs entered the internal vertebral venous plexus directly at the levels of C7 and T1 and have not been described in other rodents. Serial histological sections, revealed no regulatory valves in vessels leading toward the internal vertebral venous plexus, allowing blood to presumably move in both directions within the vertebral venous plexus. The vertebral venous plexus of B. suillus shows similarities to that of the rat but the vessels from the forelimbs draining directly into to the internal vertebral venous plexus and the position of the azygos vein and the intercostal veins draining into the external vertebral venous plexus are notable exceptions.

The colonic groove or furrow: a comparative morphological study of six species of African mole-rats (Rodentia, Bathyergidae).

Herbivorous mammals such as nutrias, guinea pigs, chinchillas, and mole-rats have a longitudinal mucosal colonic groove (furrow) in their ascending colon, which is thought to play a role in the colonic separation mechanism (CSM). It is not known whether this groove is structurally modified to adapt to this function in mole-rat species. The morphology of this groove was studied in 32 mol-rats, four species, one of which consisted of three subspecies, endemic to southern Africa and two species found in eastern Africa. The macroscopic morphology of the groove was documented, and samples for histological examination were taken. The groove was wide at its origin at the cecocolic junction and was lined on either side by a row of papillae with the opposing papillae slightly offset in arrangement. The papillated groove gradually decreased in size toward the distal part of the ascending colon where it disappeared. This pattern was similar in all species except in Heterocephalus glaber, where the papillae were absent and the groove was lined by two longitudinal ridges. A histological examination of cross sections revealed that the mucosa covering the inner and outer walls of the groove was rich in mucous-secreting goblet cells. The walls of the groove contained smooth muscle extending from the inner circular smooth muscle layer at the base to the tips of the papillae in all species examined as well as arteries, lymphatic vessels, and prominent sinusoid-like veins. The groove could be demonstrated both macroscopically and histologically in three Bathyergus suillus fetuses of varying sizes. The sinusoid-like veins present in all grooves, regardless of macroscopic shape, suggest that they have a role in the functioning of the groove.

The topography and gross anatomy of the gastrointestinal tract of the Cape dune mole-rat (Bathyergus suillus).

The Cape dune mole-rat, Bathyergus suillus, is the largest truly subterranean rodent in the world and is restricted to sandy soil areas of the southern and South-western Cape Province. These animals are herbivorous, feeding mostly on the below ground portions of grass and geophytes. The present study was undertaken to explore whether there are any gross anatomical gastrointestinal adaptations associated with the herbivorous diet of the Cape dune mole-rat and to provide a basis for further investigations into the nutrition and ecology of this animal. The stomach was unilocular (simple) and the entire internal aspect displayed macroscopically visible glandular epithelium. The caecum was voluminous and arranged into a spiral of approximately one and a half turns. The tip of the caecum resembled a vermiform appendix and lay against the left lateral abdominal wall. The ascending colon consisted of proximal and distal portions, arranged in a large double loop and attached to each other by a fat-filled mesenteric fold. The looped, folded ascending colon filled the right side of the abdominal cavity, lying against the right dorsal, lateral and ventral abdominal wall. The internal structure of the ascending colon revealed a shallow groove, lined on either side by a row of papillae. The simple, glandular stomach in conjunction with a prominent caecum and a greatly enlarged ascending colon suggests that this animal is a hindgut fermenting herbivore, rather than a caecal fermenter, as is the case in most rodent species.

The intestine and endocrine pancreas of the African elephant: a histological immunocytochemical and immunofluorescence study.

Histological, immunocytochemical and immunofluorescence methods were employed to study the intestine and endocrine pancreas of the elephant. The histological findings were in line with those in monogastric mammals. In the mucosa of intestine, endocrine cells were immunoreactive to somatostatin, gastrin, CCK, GIP, secretin, motilin, glucagon and NPY. Nerve cells immunoreactive to somatostatin, substance P, VIP, PHI, NPY, bombesin and CGRP were detected. No immunoreactivity to neurotensin was observed, islets of the pancreas had insulin cells in their cores and glucagon and somatostatin cells in their mantles. The antisera employed failed to demonstrate PP cells in the pancreas, but NPY-immunoreactive cells were present.

Characterization of mucus glycoproteins in the intestinal mucosa of the African elephant (Loxodonta africana) following lectin histochemistry.

The glycoproteins of the small intestines, caecum and colon of three adult elephants and one recently weaned elephant calf were examined by means of lectin histochemistry. Tissue sections were histochemically stained with peroxidase-labelled concanavalin A (Con A), asparagus-pea (TPA), peanut (PNA) and wheat-germ (WGA) lectins. Con A and TPA showed no binding activity in the intestinal tract of the adult elephants or the duodenum and ileum of the elephant calf, but did show a small amount of binding activity in the caecum and colon of the calf. WGA bound very intensely throughout the intestinal tracts of the adults and of the calf--especially with the goblet cells located in the crypts of Lieberkuhn and the glands of Brunner--decreasing in intensity towards the luminal surface of the intestinal tract. PNA stained the glands of Brunner of the duodenum faintly and the goblet cells of the ileum moderately, with no staining of the caecum and faint staining of the colon. These results show the distribution of Con A-, WGA-, PNA- and TPA-binding sites, and the changes that take place in the type of glycoprotein secreted after a change in the diet of the animal.

A histocytochemical study of mucus glycoproteins or mucins in the intestinal tract of the African elephant (Loxodonta africana).

The distribution of neutral mucins, sialomucins and sulphomucins was determined histochemically in the duodenum, jejunum, ileum and colon of the African elephant (Loxodonta africana). The techniques used were periodic acid-Schiff (PAS), alcian blue/periodic acid-Schiff (AB-PAS), high-iron-diamine/alcian blue (HID-AB), alcian blue at varying pH solutions and alcian blue at high temperature after methylation and saponification. Acid mucins appear to dominate neutral mucins, the latter decreasing toward the large intestine. Sulphomucins and sialomucins occurred in almost equal amounts throughout the intestinal tract, with a slight decrease of sialomucins toward the colon.

The topography of the thoracic and abdominal organs of the Nile crocodile (Crocodylus niloticus).

The pleural cavity of the Nile crocodile is divided into two separate cavities by means of a complete mediastinum. The pleural cavity contains the lungs, while the heart is situated in its own cavity, the pericardial cavity. The pleural cavity is separated from the hepatic coelom, which contains the liver, by the post-pulmonary membrane. The hepatic coelom is separated from the peritoneal cavity by the post-hepatic membrane. The peritoneal cavity contains the abdominal organs.

A light microscopical study of the intestinal tract of the Nile crocodile (Crocodylus niloticus, Laurenti 1768).

Although the histology of the intestinal tract of Crocodylus niloticus is touched on in overall studies on reptilian intestinal tract, a more comprehensive light microscopical study on this area is lacking. Specimens for histological examination were taken from the duodenum, the jejunum, the ileum and the rectum. The data obtained revealed that the mucosa is thrown into folds and simple, slightly branched tubular intestinal glands. The mucosal folds diminished in height and eventually disappeared upon reaching the ileorectal junction. The epithelium covering the folds and crypts was of the simple columnar type. Clear marginal cells, goblet cells and argentaffin cells were observed throughout the intestinal tract. No Paneth cells were seen in this study. The lamina propria was rich in lymphocytic infiltrations while the muscularis mucosa consisted mainly of an outer longitudinal layer, the inner circular layer being rudimentary or absent. The submucosa was extremely narrow, and the circular and longitudinal layers of the tunica muscularis contained distinct layers of dense fibrous connective tissue. The histology of the intestinal tract of C. niloticus is shown to be in line with the situation in crocodilians and also exhibits a resemblance to that of carnivorous mammals.

Specialized veins in the submucosa of the equine ileocecal junction.

Spirally arranged bundles of sub-endothelial smooth muscle enfold the small to medium-sized submucosal veins in the equine ileocecal junction. The muscle bundles, accompanied by the endothelial lining, bulge into the lumen of the vessels, partly occluding the latter. Transmission electron microscopy of the muscle cells reveals features consistent with vascular smooth muscle ultrastructure. It is proposed that the throttling effect of the muscle bundles causes engorgement of the submucosal venous plexus, which then assists in the closing of the ileocecal orifice.

Bioactive peptides and serotonin in the gut endocrine cells of the crocodile, Crocodylus niloticus (Laurenti 1768): an immunocytochemical study.

Little is known about peptide-storing endocrine cells in the gut of the Nile crocodile. As in the case of other reptiles, particularly the alligator, a limited range of peptide-storing cells was found in the gut of the crocodile. They were somatostatin, glucagon, gastrin, neurotensin and pancreatic polypeptide. The topographical distribution of cells immunoreactive to somatostatin and gastrin in the gut of the crocodile is comparable to the situation in the alligator. Glucagon and neurotensin immunoreactive cells have a much wider distribution in the gastro-intestinal tract of the crocodile compared to the alligator. Cholecystokinin and bombesin cells previously reported in the small intestine of the alligator were not detected in this study. This is the first report to demonstrate pancreatic polypeptide and serotonin immunoreactivity in the gut of a crocodilian specie.

An immunohistochemical study of various peptide-containing endocrine cells and neurones at the equine ileocaecal junction.

The ileocaecal junctions of 5 horses and 2 donkeys were examined by using antisera to the following peptides: somatostatin, glucagon, gastrin, neurotensin, vasoactive intestinal peptide (VIP), peptide histidine isoleucine (PHI), calcitonin gene-related peptide (CGRP), substance P (SP) and neuropeptide Y (NPY). Antisera to somatostatin, neurotensin and NPY demonstrated endocrine cells in the ileal- and caecal parts of the ileocaecal junction, while immunoreactivity for glucagon was demonstrated in endocrine cells of the ileal part only. Nerve cell bodies showing immunoreactivity to SP, VIP, CGRP and PHI were demonstrated in the myenteric and submucosal plexuses and were associated with small blood vessels in the submucosa of all the regions tested. Ramified nerve fibres in the submucosa immunoreactive to SP, VIP, CGRP and PHI extended to the mucosa and to small blood vessels in the submucosa. Nerve fibres showing immunoreactivity to SP, VIP and PHI extended to the circular smooth muscle layer of the ileocaecal junction.

Scanning electron and light microscopy of the mucosa of the equine ileocaecal junction.

The ileocaecal junction mucosal surface morphology of 5 horses and 1 donkey was examined using scanning electron microscopy and light microscopy. Based on differences in surface morphology, the junction could be divided into 4 distinct regions. The distal extremity of the ileum was characterized by the presence of typical finger-like villi followed by a narrow zone displaying short, stubby villi which gradually merged into a 3rd region representing the true transitional zone between the small and large intestine. In this region the villi fused, forming low ridges arranged in circular, semi-circular or S-shaped patterns. Many of the fused villi were indented at the tips giving these structures a doughnut-like appearance. The caecal portion of the ileocaecal junction formed the 4th region and was characterized by the absence of villi and the occurrence of regularly spaced crypt openings each surrounded by a slightly raised circular mound.

Arterial blood supply to the ileocaecal junction in the horse.

The arteries supplying the ileocaecal junctions of 7 horses were injected with latex via the A. ileocolica and dissected macroscopically. The same basic pattern emerged whereby a single papillary artery arising from the R. ilei mesenterialis, supplied all aspects of the ileocaecal papilla. In one instance, the papillary artery arose directly from the ileocolic artery. No collateral arterial supply to the ileocaecal junction was present in any of the specimens dissected.

The pattern of venous drainage of the equine ileocaecal junction.

The veins draining the ileocaecal junctions of horses (n = 19), donkeys (n = 3) and a plains zebra, (Equus burchelli antiquorum) were injected with latex via the ileocolic vein, and dissected. In all specimens the ileocaecal papilla was drained by 2 major papillary veins: one cranial and one caudal to the papilla. A smaller dorsal vein drained either into the cranial or into the caudal vein. The submucosal veins seemed to increase in number in the ileocaeacal junction to form a venous plexus. This plexus, together with veins from the caecum and the distal ileum immediately bordering the ileocaecal junction, drained either into the cranial or the caudal veins of the papilla. In 14 specimens both the cranial and caudal veins drained into a common vein, which opened into the V. caecalis lateralis in 10 specimens or into the R. ilei mesenterialis in 4 specimens. In 3 specimens the 2 veins opened separately into the V. caecalis lateralis. In 2 specimens the cranial vein opened into the V. caecalis lateralis, while the caudal vein drained into the R. ilei mesenterialis.

The arrangement of the muscle layers at the equine ileocaecal junction.

The muscle layers of the ileocaecal junctions of horses (n = 18), plains zebras (Equus burchelli antiquorum) (n = 3), mountain zebras (Equus zebra zebra) (n = 2), and a donkey were examined macroscopically and microscopically. The muscular tunic of the ileocaecal papilla was made up of 3 layers: an innermost circular layer which was a continuation of the circular muscle of the ileum, a central longitudinal layer which was a continuation of one part of the longitudinal layer of the ileum and an outermost layer, composed of two collateral semicircular lips, formed by the circular layer of the caecum. The other part of the longitudinal ileal muscle layer contributed to the dorsal caecal taenia. The circular and semicircular muscle layers contributed by the ileum and caecum respectively represented what could be termed as a M. sphincter ilei, which did not exist as a separate annular muscle confined only to the papilla as the name would suggest. The amount of intermuscular connective tissue increased in both these layers towards the tip of the papilla, while at the same time the layers decreased in thickness. This finding supports the view that their sphincteroid action would be less efficient and that an additional closing mechanism of vascular origin may be required at the ileocaecal papilla of the horse.