الفهرس 
Aim of The WorkOnly 14 pages are availabe for public view
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Abstract
Amiodarone is the most commonly used antiarrhythmic drug. It causes multiple hazardous effects as thyroid dysfunction.
L-carnitine is a natural tri-methylated amino acid that plays an important role in cell energy metabolism. It has antioxidant and anti-inflammatory effects on various pathophysiological conditions.
Exosomes are now recognized as natural vehicles involved in intercellular communication.
The present study aimed to evaluate the possible ameliorating effect of bone marrow mesenchymal stem cells derived exosomes and L-carnitine on amiodarone induced thyroid follicular cells toxicity in adult male albino rats.
The present study was performed on 72 adult male albino rats. Animals were divided into 7 groups as follows:
group I (control group: n=12 rats).
group II (amiodarone treated group: n=10 rats): It was administered orally in a daily dose of 60 mg/kg body weight for 6 consecutive weeks, so each rat received about one milliliter of solution.
group III (L-carnitine treated group: n=10 rats): The rats were received amiodarone for 6 weeks, then they were given L- carnitine by intraperitoneal injection in a dose of 500 mg/ kg daily for four weeks.
group IV (Exosomes treated group: n=10 rats): The rats were received amiodarone for 6 weeks, then they were given three doses of exosomes for 4 weeks. Each dose is at a concentration of 100μg BMSC-EX diluted in 0.5 ml PBS, injected intravenously over 5 min via tail vein. Six rats from the ten will be scarificed immediately after the last dose of exosomes forming group IV. The other four rats stay another 10 days from the last dose forming a new group (group VII).
group V (L-carnitine and Exosomes treated group: n=10 rats): The rats were received amiodarone for 6 weeks, then they were given L-carnitine concomitant with the three doses of MSC-exosomes till being scarificed after 4 weeks.
group VI (recovery group: n=10 rats): The rats were received amiodarone as mentioned before, then they were scarificed at the end of experiment without taking any treatment.
group VII (Exosomes withdrawal group): The four rats remaining from ten rats mentioned previously in group IV were scarificed after 10 days from the last dose of exosomes to determine whether the improvement occured by exosomes would increase, decrease or remain constant after 10 days.
By the end of the experiment animals were scarificed and specimens from thyroid gland were collected and prepared for histological study (H&E stain, Masson trichrome stain, ki-67 immunostaining and electron microscopic study) and blood samples for biochemical assay.
The study showed the following results:
group II (affected group): In this study group II showed by H&E stain loss of normal follicular architecture. The follicles were disorganized, ruptured and fused. The follicular epithelial cells formed from more than one layer. Cells were severely vacuolated with abnormal dark nuclei. Some follicles showed desquamated epithelium forming clusters in the lumen. The interfollicular tissue showed markedly congested blood vessels and mononuclear cellular infiltrates. There was also a significant increase in collagen fibers revealed by Masson trichrome staining and a significant increase in Ki-67 immunostaining.
Examination of ultrathin sections of the thyroid gland of rats of this group showed follicular epithelium with irregular nuclei containing abnormal dispersed chromatin. The cytoplasm showed vacuolization with markedly dilated rough endoplasmic reticulum. The mitochondria were degenerated. The apical free surface showed broken microvilli.
There was a significant increase in the levels of serum TSH and a significant decrease in free T3 and T4 levels in this group compared to control.
group III (L-carnitine treated group): Examination of hematoxylin and eosin stained sections of the thyroid gland of rats of group III showed mild structural improvement. It showed disorganized, irregular and variable sized thyroid follicles lined with vacuolated follicular epithelium with abnormal dark nuclei in some areas. Clusters of nuclei inside the lumen of follicles indicating desquamated epithelium. The Interfollicular tissue showed congested blood vessels and mononuclear cellular infiltrates. There was also a significant decrease (p<0.01) in both collagen fibers deposition revealed by Masson trichrome staining and Ki-67 immunostaining expression compared to group II.
Examination of ultrathin sections of thyroid gland of rats of this group showed follicular epithelium with irregular nuclei. The cytoplasm showed dilated rough endoplasmic reticulum, degenerated mitochondria. The apical free surface showed broken microvilli.
There was a decrease in the levels of serum TSH and an increase in free T3 and T4 levels in this group compared to group II.
group IV (exosomes treated group): It showed moderate structural improvement compared to groups II and III. It showed variable sized thyroid follicles lined with vacuolated follicular epithelium containing apparently normal nuclei in some areas. Interfollicular tissue showed mononuclear cellular infiltrates apparently less than present in group III. There was also a significant decrease (p<0.01) in both collagen fibers deposition revealed by Masson trichrome staining and Ki-67 immunostaining expression compered to groups II and III.
Examination of ultrathin section of thyroid gland of rats of this group showed follicular epithelium with slightly irregular nuclei. The cytoplasm showed mildly dilated rough endoplasmic reticulum, apparently normal mitochondria and many lysosomes. The free surface showed partially apical broken microvilli.
As regards the biochemical results emerged from the present study, there were a decrease in the levels of serum TSH and an increase in free T3 and T4 levels in group IV compared to groups II and III.
group V (L- carnitine and exosomes treated group): It showed marked structural improvement compared to groups II, III and IV. Thyroid follicles appear more or less as control. But, there was widening in inter follicular connective tissue and Blood vessels showed mild congestion. This group also showed a significant decrease (p<0.01) in both collagen fibers deposition and Ki-67 immunostaining expression compered to groups II, III and IV.
Examination of ultrathin section of thyroid gland of rats of this group showed follicular epithelium with regular nuclei with euchromatic peripherally located chromatin. The cytoplasm showed apparently normal rough endoplasmic reticulum, mitochondria and many lysosomes. Apical Free surface showed many microvilli.
As regards the biochemical results emerged from the present study, there were a decrease in the levels of serum TSH and an increase in free T3 and T4 levels in group V compared to groups II, III and IV.
group VI (recovery group): It showed little improvement compared to group II. Thyroid gland sections of this group showed disorganized, irregular and variable sized thyroid follicles. Some follicles showed desquamated epithelium forming clusters in the lumen. Blood vessels showed marked congestion. Interfollicular tissue showed mononuclear cellular infiltrates. This group also showed a significant increase in the collagen fibers revealed by masson trichrome stain and strong positive nuclear immunostaining reaction for Ki67.
Examination of ultrathin sections of the thyroid gland of rats of this group showed showed marked vacuolization with markedly dilated rough endoplasmic reticulum, degenerated mitochondria and many lysosomes. The free surface showed apical broken microvilli. The lumen showed clusters of desquamated follicular cells.
As regards the biochemical results emerged from the present study, there were a significant increase in the levels of serum TSH and a significant decrease in free T3 and T4 levels in this group compared to the control group.
group VII (exosomes withdrawal group): Examination of hematoxylin and eosin stained sections of the thyroid gland of rats of group VII showed to some extent the same results of group IV (exosomes treated group). It showed moderate structural improvement compared to groups II and III. It showed variable sized thyroid follicles lined with vacuolated epithelium with apparently normal nuclei in some areas. Interfollicular tissue showed mononuclear cellular infiltrates. There was a significant decrease (p<0.01) in both collagen fibers deposition and Ki-67 immunostaining expression compered to groups II and III.
Examination of ultrathin section of thyroid gland of rats of this group showed follicular epithelium with slightly irregular nuclei. The cytoplasm showed dilated rough endoplasmic reticulum, mitochondria and many lysosomes. The free surface showed partially apical broken microvilli protruding in the follicular lumen.
As regards the biochemical results emerged from the present study, there were a decrease in the levels of serum TSH and an increase in free T3 and T4 in group VII compared to groups II and III.
Conclusion: L-carnitine and exosomes enhanced the repair of amiodarone induced thyroid follicular cells injury with little differences in their effectiveness. The effect of exosomes is better than L-carnitine. The L-carnitine and exosomes together revealed more increase in effeciency than exosomes alone.
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