الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Giardiasis is a common cause of diarrhea in both adults and children. It has a global distribution and it is transmitted via the fecal-oral route through direct or indirect ingestion of cysts. The clinical manifestations of giardiasis range from asymptomatic carriers to both chronic and acute diarrhea with or without other gastrointestinal manifestations. Up till now, metronidazole (MTZ) is the standard therapy for giardiasis. However, it has many side effects as nausea, metallic taste, and hepatic damage. Also, drug resistance to metronidazole has become increasingly prevalent. Consequently, it has been necessary to find new alternative regimens with high efficacy and low toxicity as plants or herbs for treatment of giardiasis. Pomegranate peel extract (PPE) which contains many biologically active components may be active against many pathogens, and it was used as an alternative and effective medication for treatment of diarrhoea. With the rapid growth of nanotechnology, different nanoparticles have been presented for medical application as they improve the bioavailability of drugs and decrease their side effects. Chitosan is a natural polysaccharide used in nano medicine because of its distinctive properties for drug carriage and its NPs are found to be efficient at enhancing drug uptake. The present work was conducted to evaluate potential effects of pomegranate peel extract and metronidazole loaded on chitosan nanoparticles in treatment of experimental giardiasis .In the present study, the drugs used showed different degrees in decreasing counts of G. intestinalis cysts. But, none of them gave a complete eradication of cysts.
The morphology (size and shape) of CsNPsand drugs loaded nanoparticles (Pomegranate peel extract loaded CNPs and metronidazole loaded CNPs) using TEM are 22.23-40.62, 72.63- 85.14, 60.57-74.72 μm respectively and its shapes were crystallites in CsNPs and spherical in each of PPE/CsNPs and MTZ/ CsNPs.
On the other hand, zeta potential of Cs was 15.4 whereas the zeta potential of MTZ/CsNPs was 17.7 and the zeta potential of PPE/CsNPs was 16.2 . Regarding Fourier Transform infrared spectroscopy (FTIR) spectra of chemically prepared nanoparticles, Cs
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showed characteristic peaks at 3436.18 (for stretching vibration of OH and NH2), 2075.68 (C–H bond vibrations in alkanes), 1650.72 (C=O bond vibrations in the amide I molecules), 1394.41 (general OH groups bending), 1278.96and 1016.26 (corresponds to the stretching vibrations of C–O–C bonds), and 665.97cm−1. MTZ/Cs showed a peak at 1650.44cm-1 (attributed to the amide group in chitosan) and a peak at 1644.24cm-1 (ascribed to –NH2 in chitosan). The peak corresponding to P=O was observed at 1453.34cm-1. Regarding PPE, the band 3383.50 cm−1 is ascribed of N–H and O–H groups, which can be possibly found in tannic acid, gallic and ellagic acid. The peaks at 2079.80 and 1634.39 cm−1 were attributed to C–H, C=O, and carbonyl groups. On the other hand, drugs loading efficiency was estimated by spectrophotometric method, they were found to be 54% in PPE/Cs at 472 nm and 47% at 330 nm in MTZ/Cs. 96509.3
According to the parasitological studies, all rats of control and experimental groups did not show any abnormal clinical signs. All rats survived and were in good health with normal behavior throughout the experiment. Regarding G. Intestinalis cysts count and reduction percentage, the lowest cyst count was observed in MTZ treated rats (mean cyst count per gram stool. CPG)= 1189.7±302.2 and reduction percentage 98.8%) followed by PPE treated rats (mean CPG =4102.3±2564.3 and reduction percentage =95.7%) and MTZ/Cs treated rats (mean CPG =16751±9141.7 and reduction percentage =82.5%)
The Cs and PPE/Cs were the least effective showing mean CPG of 24302.7±30183 and reduction percentage =74.8% and mean CPG of 32325.2±24671 and reduction percentage =66.5% respectively.
Regarding toxicity studies, there was a significant difference in mean ALT level between the studied groups (F= 8.275 and P value < 0.001). The lowest ALT level was observed in infected PPE treated rats (mean=42.67±17.34) while the highest level was found in infected CsNPs treated rats (mean=86.33±13.43). On the other hand, there was a significant difference between the studied groups regarding the mean AST level (F= 7.856 and P value < 0.001). The non-infected PPE treated subgroup showed the lowest AST level (mean=89.67±23.80) while infected MTZ treated subgroup showed the highest level (mean=240.7±29.74).
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Regarding kidney function tests, there was a significant difference between the studied groups regarding the mean serum creatinine level (F= 5.190, P < 0.001). The lowest level was observed in the non-infected MTZ/Cs treated subgroup (mean =0.78± 0.15) while the highest levels were found in infected CsNPs, MTZ and PPE treated subgroups (levels= 1.85±0.98, 1.82±0.36 and 1.72±.0.33 respectively). On the other hand, there was a significant difference between the studied groups regarding the mean blood urea level (F= 3.899, P < 0.001). The lowest level was observed in the non-infected MTZ/CsNPs treated subgroup (mean =36.83±4.96) while the highest level was found in the infected MTZ treated subgroup (level= 64.32±12.52)
SEM showed that Giardia trophozoites in samples collected from non-treated rats were pear shaped, had smooth surface and intact flagella and showed normal appearance of the sucking disc. Cysts were oval and had smooth intact outer wall. In treated rats, trophozoite deformations with loss of the characteristic pear shape, mutilations and dimples on the outer surface, distortion of the sucking disc and loss of the flagella were observed. Cysts exposed to different treatments were distorted and showed perforations and damage of the outer wall.
Histopathological changes of the intestine of infected non-treated rats showed marked destruction and shortening of intestinal villi with irregular sharp microvillus border, many residual undifferentiated debris and thick lamina propria with many infiltrating lymphocytes. The intestine of infected treated rats showed variable degrees of mucosal recovery with smooth microvillus border and elongated intestinal villi.
In conclusion, PPE and PPE loaded CsNPs have promising antigiardial action that reduces Giardia cyst counts, improves histopathological alterations in intestinal mucosa and induces ultra-structural damage of this protozoan parasite without inducing overt hepatic or renal adverse effects in the infected host.
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Recommendations
Further studies should focus on:
1- Testing the anti-Giardial action and toxicity of higher doses of PPE and PPE/CsNPs.
2- Comparison of the anti- Giardial action of water and alcoholic extract of PPE.
3- Separation of active ingredients of PPE such as poly phenols, loading it on chitosan nanoparticles and testing its effect in experimental giardiasis.
4- Evaluation of PPE seed extract alone and in combination with peel extract in treatment of giardiasis
5- Studying the effect of PPE on different Giardia assemblages
6- Studying the action of PPE and PPE loaded CsNPs and other nanoparticles against different parasites
7- Studying the effect of using PPE as complementary treatment to enhance the efficacy of other anti-parasitic drugs.