الفهرس 
مقدمه الدراسهOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
Scorpion stings are a major public health and veterinary problem in
tropical and sub-tropical countries. Most of the scorpions that are dangerously
venomous to humans and animals belong to buthidae family (Gary and
Lance, 2009). Buthidae is the largest and most widespread scorpion family.
Around 72 currently recognized genera and at least 528 species are classified
under this family.
Leiurus quinquestriatus (L. Q.) scorpion is one of the most important
members of buthidae family. It is reported as one of the most dangerous
scorpions in the world. This is because its venom is a powerful cocktail of
neurtoxins with a low LD50 (Lucian, 2008).
The scorpion’s venom is comprised of a variety of compounds including
low-molecular-weight proteins, neurotoxins, histimine, seratonin, enzymes,
enzyme inhibitors, and other unidentified compounds (Possani et al., 2000).
According to the molecular size; The neurotoxins of L.Q. are classified into
the short chain toxins composed of 20 – 40 amino acid residues with three or four
disulfide bonds, including chlorotoxins and charybdotoxins, which affect chloride
or potassium channels. The long-chain toxins have 58 – 76 amino acid with
four disulfide bonds and affect mainly the sodium channels (Mouhat et al.,
2004).
The reported LD50 of L.Q. venom is ranged from 0.16 - 0.5mg/kg in different
animals; which confirm the severity of this species of scorpion (Gueron, et al.,
1992).
The voltage dependent ion channels; sodium, potassium and calcium
channels; are the main targets of scorpion venom action. The symptoms of
scorpion envenomation result from a complex interaction of parasympathetic and
sympathetic stimulation along with the release of a variety of endogenous
compounds including catecholamines, angiotensin II, glucagon, corticosteroids,
bradykinins, prostaglandins, and cytokines. Fatalities are primarily the result of
cardiovascular and respiratory dysfunction and failure (Cupo et al., 2007)
Although the toxicity of L.Q. venom has been studied by several groups all
over the world, it still needs several investigations. The purpose of this study is to
investigate in vivo the pathological, hematological and biochemical changes
associated with Leiurus quinquestriatus crude venom injection on female rabbits.
In Egypt, envenomation by scorpions represents a serious public health
and veterinary problem. Leiurus quinquestriatus scorpion was reported to be one
of the most dangerous scorpions worldwide. In the present study; clinical,
histopathological, hematological and biochemical investigations had been done
in female rabbits after L. Q. crude venom injection.
A total number of 30 female California rabbits have been used in this
study. A single dose of crude L.Q. venom of 0.4mg/kg was injected i.v in
peripheral ear vein. Blood samples have been collected pre – and post –
envenomation in a time course started from zero up to eight days for the
hematological and biochemical investigations. Histo-pathological examination of
different body organs have been carried out postmortem. Three animals have
been used per time point.
Respiratory distress and nervous manifestations were the predominant
symptoms after envenomation. These include tremors, convulsions and hurried
respiration directly after envenomation; while dyspnea, recumbency and
paralysis of the hind limbs was observed at the late stage.
Wide spread congestion and hemorrhage at different body organs was
obvious in the postmortem examination; with the lung, brain and heart being the
most affected organs. On the other hand the lung body weight index revealed
edematous enlargement of the lung post envenomation.
The histopathological examinations of the lung showed sever affection.
Edema, hemorrhage, emphysema of the lung and damage of the bronchial
epithelium were the predominant findings at the most of the tested time points.
Histopathology of the brain showed liquifactive necrosis and demylination
expressed by vaculation at most of envenomation intervals. Irreversible
myocardial damage which was obvious by necrosis and oedema was evident in
this study. Nephrotoxicity was also obvious after envenomation by necrosis of
glomerular tuft and renal tubules, interstitial hemorrhage and hyaline casts. The
spleen showed hyperplasiwhile exhaustion of lymphoid follicles was evident by 24h post envenomation.
The hepatic changes observed in the present study started as sinusoidal
dilatation, hepatocytes degeneration and ended by hepatocytes necrosis by day
post after envenomation. The genital organs in the present study showed
hyperemia of blood vessels in early stages of envenomation followed by wellexpressed inflammation of the ovaries by Twenty four-hours. By day eight post
envenomation; all body organs appeared free from any morphological alterations
in comparison to the controla of lymphoid follicles after 30min. from envenomation;