Role of bacterial DNA on cell death in neutrophils

العناوين الأخرى

دور الدنا البكتيري في الموت الخلوي للعدلات

مقدم أطروحة جامعية

al-Alusi, Nawafil Salim Khalaf

مشرف أطروحة جامعية

al-Mathkhuri, Harith Jabbar Fahd
Yusuf, Hana Salim

أعضاء اللجنة

al-Dulaymi, Hind H.
Jasim, Hamid Majid

الجامعة

جامعة بغداد

الكلية

كلية العلوم

القسم الأكاديمي

قسم علوم الحياة

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2012

الملخص الإنجليزي

Apoptosis of neutrophils is an important mechanism by which neutrophils are removed from sites of inflammation.

Cellular processes of apoptosis are dysregulated by signals from the environment that may delay apoptosis, resulting in their prolonged survival, which is important in the persistence of tissue inflammation and may be its damage.

This study aimed to investigate the role of a bacterial component, DNA, in the apoptosis of neutrophils and whether this effect is related to CpG oligonucleotide.

Between August and November 2010 a total of 106 mid-stream urine specimens were obtained from patients clinically suspected to have urinary tract infection (UTI) referred to Al-Kadhmiah Teaching Hospital, Al-Yarmouk Teaching Hospital, Al-Nadha’ir Almushi’a Laboratory and Baghdad Lab for Pathologic Analysis.

E.

coli was involved in 37 (34.91 %) of total urine specimens (59.68 % of Enterobacteriaceae) whereas S.

aureus was involved in eight (7.55 %) of total urine specimens (33.33% of Staphylococcaceae).

The isolates (E.

coli and S.

aureus) with the highest susceptibility against β-lactam antibiotics were processed for whole genome DNA extraction and purification.

Human neutrophil cells were isolated from blood of healthy volunteers and were exposed, in vitro, to different concentrations (400, 800 and 1600 ng/ml) of the purified bacterial DNA.

Furthermore, three different concentrations (2, 4 and 8 μg/kg) of the bacterial DNA were injected intravenously into healthy male Wister rats, thereafter, blood was collected and cells were isolated.

Both cell suspensions of the in vitro and in vivo studies were incubated at 37°C for different periods, the apoptosis rate was considered for each test group morphologically.

Furthermore, agarose gel electrophoresis was SUMMARY IX assessed for the purified bacterial DNA as well as DNA extracted from cells undergoing apoptosis (for the detection of DNA fragmentation).

The results of the present study revealed statistically (P< 0.05) observable effects of different concentrations of DNA from both bacterial species on apoptosis of neutrophil cells in vitro and in vivo.

These effects were correlated negatively with DNA concentration implying the best effect to the 1600 ng/ml (in vitro) and 8 μg/kg (in vivo).

Furthermore, this delaying effect on apoptosis was more observable with E.

coli DNA than S.

aureus DNA.

The highest in vitro apoptotic recording was after 24 h for the control group (62.33±2.52 ), while the lowest recording was for groups treated with DNA of E.

coli and S.

aureus (16±3 and 38.33±2.52, respectively) where 1600 ng/ml bacterial DNA was used.

In regard to in vivo study, at the same concentration of E.

coli and S.

aureus DNA recorded 8.33±1.53 and 59.33±0.58, respectively.

In conclusion, results of this study supported the hypothesis that bacterial species differ in their DNA-dependent delaying capacity of neutrophil apoptosis, which may contribute to prolongation and amplification of inflammation.

Moreover, these results support the view of a CpG contentdependent immunostimulation in bacterial DNA.

التخصصات الرئيسية

الأحياء

الموضوعات

• علم الوراثة

عدد الصفحات

127

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-603182