Rat large intestine is an established model to study the effect of
carcinogens. There are several distinctive features among mammalian gastrointestinal
tracts in gross anatomy but they share some basic similar structures. The variety in
digestive system relies on its physiology. Rats rarely eat high fatty diets, thus the
function of gall bladder become less significant in their digestive system and this is
justified by the fact that rats have none. Rats have large caecum designated for their
fermentation chamber to digest cellulose. Another notable difference is the size and
length of colon itself, in which human colon is significantly bigger and longer. We aimed
to demonstrate the gross anatomy and histology of rat digestive system particularly the
large intestine. (Copied from article).
Introduction: Over the decades, organic arsenic has been thought to be less toxic than inorganic arsenic.
Monosodium methylarsonate (MSMA) is a potent organoarsenical herbicide that is still being used in most
Asian countries. Reported studies on the effects of organic arsenic are mainly to the gastrointestinal system,
however there are limited research on its impacts to the liver. Therefore, this study aimed to investigate the
effect of MSMA exposure on hepatocytes and liver sinusoidal endothelial cells (LSEC). Materials and Methods:
Fourteen Sprague Dawley rats (n=14) were divided equally into arsenic-exposed (n=7) and control (n=7)
groups. The rats in arsenic-exposed group were given MSMA at 63.20 mg/kg daily for 6 months through oral
gavage. While the rats in control group were given distilled water ad libitum. At the end of the duration,
they were euthanized and underwent liver perfusion for tissue preservation. Liver tissues were harvested and
processed for light microscopy, scanning and transmission electron microscopy. The findings were analysed
descriptively. Results: MSMA had caused necrotic and apoptotic changes to the liver. Normal organelles
morphology were loss in the hepatocytes while LSEC revealed defenestration. Conclusion: In this study,
chronic low dose organic arsenic exposure showed evidence of toxicity to hepatocytes. Interestingly, LSEC
demonstrated capillarization changes.
Monosodium methylarsonate (MSMA) is an organic arsenical pesticide widely used in agriculture. Humans are exposed to arsenic through drinking water and anthropogenic activities. Exposure to inorganic arsenic has been linked with multiple health problems. However, studies focusing on chronic organic arsenic exposure and its adverse effects on kidney were limited. The purpose of current study was to determine the effects of chronic organic arsenic exposure in rats kidney by light and electron microscopy. Materials and Method: Thirty-six male SpragueDawley rats were divided into six groups (n=6); three control and three treatment group respectively. All the control group was given distilled water via oral gavage. The treatment group was given oral gavage of MSMA at 42.10 mg/kg body weight (BW) which is equivalent 1/30 LD50 of MSMA. The control and treatment groups were sacrificed at two month, four month and six months interval. Both kidneys harvested for light microscopy and electron microscopy study. Results: Showed progressive changes. The changes initially focal and became diffused involving glomerular; such as glomerular hypercellularity, glomerular shrinkage and dilated Bowman's space. Meanwhile, in proximal tubules, showed diminished brush borders, detachment of nucleus and basement membrane thickening. Electron microscopy showed flattened cell bodies of podocytes, effacement and fusion of podocytes foot processes, thickening of glomerular basement membrane, and discontinuity of brush border. The control and two-months treated group appeared to be normal. Conclusion: Chronic organic arsenic (MSMA) exposure induced chronic kidney injury.
Liver perfusion has been the standard method to digest and isolate liver
cells including liver sinusoidal endothelial cells (LSEC). Poor cannulating skills through
portal vein results in a waste of animal resource. Familiarization of both liver perfusion
technique and adhering strictly to aseptic technique during cell handling ensure high
cell yield, minimum morphology disruption and cell contamination. We aimed to present
a method of liver perfusion procedure followed by the isolation of LSEC. (Copied from article).
A novel injectable calcium phosphate bone cement (osteopaste) has been
developed. Its potential application in orthopaedics as a filler of bone defects has been
studied. The biomaterial was composed of tetra-calcium phosphate (TTCP) and tricalcium
phosphate (TCP) powder. The aim of the present study was to evaluate the
healing process of osteopaste in rabbit tibia.(Copied from article).