الفهرس 
Parkinson’s DiseaseOnly 14 pages are availabe for public view
 |  | from | 236 |  |  |
| | | from | 236 | | |
Abstract
SUMMARY AND CONCLUSION
Parkinson’s disease (PD) is one of the most common
neurodegenerative disorders. It is the second one after alzheimer’s
disease. It characterized by loss of dopamine producing cells of the
substantia nigra pars compactica (SNpc), the loss of these neurons
produces the motor features of the disease. The process is a slowly
progressive and motor symptoms start to appear after degeneration
of 50-60% of the SNpc, the pathological hallmarks of the disease are
loss of nigrostriatal dopaminergic cell and the presence of
intraneuronal eosiphilic proteinacious inclusions known as “Lewy
bodies”, the cause of PD remains unknown. But may be due to
genetic or familial Causes. About 5% of cases occur in young age
and the remaining 95% of the cases are sporadic for which no
specific etiology can be found. Pakinsonian symptoms can also
occur as a side effect to dopamine blocking drugs eg., neuroleptics,
especially the classic drugs eg, haloperidol, cinnarizine, may due to
repeated head trauma, viral infection, or poisoning due to manganese
or rotenone this is called secondary parkinsonism.
The most common model of Parkinsonism which gives the
same neuronal changes in animal as in human is rotenone. Rotenone
is plant derived pesticide and a complex I (NADH-quinone oxidoreductase)
inhibitor in oxidative phosphorylation chain of the
mitochondrial respiration, the inhibition of complex I formation
leads to ATP depletion, which induces oxidative stress in cells.
Rotenone is also known to induce apoptosis, induces microglia
activation and loss of dopaminergic neurons in model of Parkinson’s disease and also inhibits microtubule polymerization and arrest cell
cycle progression at mitosis.
L -dopa is a corner stone in treatment of parkinsonism but
not used alone used in combination with carbi-dopa to prevent
peripheral decarboxylase enzyme and increase L-dopa level, it used
for prevention and treatment of parkinsonism. It is the main source
of dopamine in brain as it pass blood brain barrier and turned to
dopamine by decarboxylase enzyme .
Colchicine is a plant alkaloid, which used in treatment of
acute gouty attacks it reduces frequency of acute attacks and relieves
pain. It has a suppressive and prophylactic effect. Colchicine inhibits
the synthesis and release of leukotrienes, inhibits neutrophil activity
and migration to the affected area leading to anti-inflammatory
effect, beside its anti-mitotic effects it has anti-inflammatory, antioxidant
and anti-apoptotic properties and difficulty in passing to
blood brain barrier disappears in Pakinsonian patients due to
depression of the p-glycoprotein efflux system. According to these
clinical data we used colchicine as possibly neuroprotective drug in
the rat rotenone model of Parkinson’s disease.
Valproic acid (VPA) is used as an anti-epileptic drug but
many studies suggest that valproic acid could be used as a
neuroprotective in parkinsonism as it has many effects as anti
inflammatory because VPA reduces polymerphonuclear cells
migration, myeloperoxidase release, anti oxidant and anti apoptotic
effects as it blocks the synthesis of pro-apoptotic factors.The aim of this work is:
1. Study the potential neuroprotective effects of L- dopa,
colchicine and valproic acid on rotenone induced
parkinsonism.
2. Compare effects of colchicine or valproic acid with L- dopa
protective effect on rotenone induced parkinsonism
Methods:
This experiment was carried out using 48 male wistar rats
each weighing (120-150) gm. They were kept under similar housing
conditions and had free access to food and water. They were divided
into 6 groups each group consist of 8 rats as follow:
group (1): normal control group rats received distilled water orally.
group (2): rats received carboxy methyl cellulose (CMC) 0.5% as a
vehicle (1 ml /kg subcutaneous S.C. once daily for 28
days).
group (3): rats received rotenone (2mg/kg S.C. daily for 28 days
suspended in 0.5% CMC).
group (4): rats received rotenone + L-dopa (10mg/kg intraperitoneal
i.p. daily for 28 days suspended in 0.5% CMC)
group (5): rats received rotenone + Colchicine (20 microgram/kg
p.o. orally daily for 28 days suspended in 0.5% CMC).
group (6): rats received rotenone + valproic acid (1.4 gram/kg p.o.
orally daily for 28 days suspended in 0.5% CMC).All animals were evaluated throughout the experiment by the
behavioral tests for monitoring PD development at 7th day,14th day
21st day and 28th day before sacrification of all rats twenty four
hours after the last treatment (28th day) by:
1- Catalepsy test
2- The pole test
3- T maze spontaneous alternation test
At the end of the work, all rats were sacrificed. The brain of
each rat was immediately excised, washed with ice-cold saline and
the basal ganglia of the two hemispheres were dissected. The left
basal ganglia were immediately immersed in 10% formalin and used
for light microscopic histopathological examination and
Immunohistochemical evaluation of caspase-3.The right basal
ganglia were homogenized in phosphate buffer saline (PBS)and
centrifuged at 4000 rpm for 20 minutes. The supernatants were
collected and frozen at -80oC for further assay of the following
parameters in basal ganglia:
Tissue dopamine level.
Tissue tumor necrosis factor alpha (TNFα)
Tissue reduced glutathione level (GSH)
Results:
Injection of rotenone (2mg/kg S.C. daily for 28 days suspended in
0.5% CMC) for 28 days induce Parkinson model. There
was significant difference between that group and control
(receive distilled water), vehicle group (receive CMC0.5%) in behavioral tests as catalepsy test (grid test and
bar test) there was increase in time for that catalepsy test
which indicated rotenone toxicity and dopaminergic
neurons degeneration and appearance of rigidity,
bradykinsia and slow motion which started at 7th day and
increased at 14th day, 21st day and 28th day. At the end of
our study rats were suffered from severe
neurodegeneration.
In T maze spontaneous alternation test there was
deterioration in memory started from 7th day, 14th day and reached
severe impairment of memory and cognition at 21stday and 28thday.
In the pole test which record time for locomotor activity, there was
increase in time taken for rats to reach the base of wooden pole and
there was sliding and dropping of many rats in the group, that was
started at 7thday, 14th day and became severe and all rats of that
group were slidded and dropped at 21st day and 28thday.
There was significant changes in neurochemical parameters
when compared to control group (received CMC), L-dopa treated
group, colchicine treated group and valproic acid treated group as
significant decrease in tissue dopamine level, significant decrease in
tissue reduced glutathione level (GSH). Significant increase in tissue
tumor necrosis factor α (TNFα). In histopathological features there
was severe neuronal cell death, structural damage to the substantia
nigra, there was distribution of lewy bodies and severe inflammation
with huge edema and significant increase in vacuolated cells number
in substantia nigra. In immunohistochemistery there was strong
positive caspase 3 reactions and severe degree of apoptosis, so that group has high histopathological and immunohistochemistery scores
than control group (received CMC), L-dopa treated group,
colchicine treated group and valproic acid treated group.
Regarding to L-dopa treated group, the current results
showed significant improvement in behavioral tests as catalepsy test
(grid test and bar test) there was significant decrease in time for that
test which started at 7th day and improved at 14th day, 21st day and
28th day when compared with rotenone treated group and valproic
acid treated group. But results nearly similar to colchicine treated
group, significant results were recorded in T maze spontaneous
alternation test there was deterioration in memory started at 7th day,
14th day, 21st day and 28th day but better than results in rotenone
treated group and valproic acid treated group and there was
improvement in memory and cognition at the end of our study than
rotenone treated group, colchicine treated group and valproic acid
treated group.
In the pole test which record time for locomotor activity,
there was significant decrease in time taken to rats to reach the base
of wooden pole and there was very few rats were slidded and
dropped in the group, that was started 7thday, 14th day and became
improve in all rats of that group at 21st day and 28th day that were
significant results in comparison to rotenone treated group,
colchicine treated group and valproic acid treated group. There was
significant improvement in neurochemical parameters when
compared to rotenone treated group and valproic acid treated group
as significant increase in tissue dopamine level, significant increase in tissue reduced glutathione level (GSH), with significant decrease
in tissue tumor necrosis factor α level (TNFα).
In histopathological features there was mild neuronal cell
death, structural damage to the substantia nigra, no lewy bodies,
mild inflammation with edema and very low number of vacuolated
cellsin substantia nigra which more better than group (treated by
rotenone) and valproic acid treated group and nearly similar to
colchicine treated group. In immunohistochemistery there was
nearly negative caspase 3 reaction and mild degree of apoptosis,so
that group has very mild histopathological and immunohistochemistery
scores than rotenone treated group and valproic acid
treated group.
Regarding to colchicine treated group, significant results
were appeared in behavioral tests as catalepsy test (grid test and bar
test) there was decrease in time for that test which started at 7th day
and improved at 14th day, 21st day and 28th day when compared with
rotenone treated group and valproic acid treated group, significant
results were recorded in T maze spontaneous alternation test, there
was deterioration in memory started at 7th day, 14th day,21st day and
28th day but colchicine got improvement of memory deterioration
comparing to rotenone treated group and valproic acid treated group.
Improvement in memory and cognition at the end of our study and
nearly similar to L-dopa treated group.