The roles of dysregulation of microbiota-gut-brain axis in morphine analgesic tolerance and hyperalgesia.
China (IFMSA-China) - Soochow University, Suzhou
Institute of Neuroscience
Tong LIU
English, Chinese
4 weeks
Cities/Months Jan Feb Mar Apr May Jun Jul Augt Sep Oct Nov Dec
No No No No No No Yes Yes No No No No
Type of Research Project
- Basic science
What is the background of the project?
Morphine is the most effective opioid for relieving moderate and severe pain at present, but long-term application of morphine can cause tolerance and addiction, which limits its clinical application. The dysregulation of microbiota-gut-brain axis plays a key role in many kinds of neurological diseases, but its role in morphine tolerance and hyperalgesia is still unclear. In our previous study, we found that the gut microbiota in morphine tolerance mice was disturbed, the intestinal permeability was significantly increased, and translocation of the intestinal bacteria happened. Morphine tolerance and neuroinflammatory responses in dorsal root ganglia and spinal cord were significantly reduced in mice treated with antibiotics cocktail or in toll-like receptor 2 knockout mice. Therefore, we proposed a hypothesis that dysregulation of microbiota-gut-brain axis plays a key role in morphine tolerance and hyperalgesia in mice.
What is the aim of the project?
This study aims: 1) to clarify the mechanism underlying morphine-altered gut microbiota community and enhanced intestinal permeability and its association with morphine tolerance and hyperalgesia; 2) to clarify the mechanisms for neuroinflammation induced by morphine via gut microbiota products; 3) to elucidate the mechanisms underlying the hyperexcitability of dorsal root ganglia neurons induced by long-term morphine treatment.
What techniques and methods are used?
1. Animal behavior testing will be used study the reaction of mice to harmful stimulus, including: λ Tail-flick test: a container of liquid is heated or cooled to a nociceptive temperature – normally 50–55 °C or below 0 °C. The animal subject is then placed with its tail immersed in the liquid, and the latency to withdraw the tail from the liquid is measured; λ Hot plate test: the test of the pain response in animals, similar to the tail flick test. This test measures the nociceptive responses of mice when they are placed on a warmed metal plate either at a standard, constant temperature or at slowly increasing temperature, starting from non-noxious levels to a standard. 2. Cell culture is used to prepare dorsal root ganglion neuron in vitro; 3. Molecular biology techniques used to study the expression of relatedproteins includes: λ Polymerase Chain Reaction (PCR); λ Western blotting; λ High-throughput Sequencing; 4. Flow cytometry 5. Immunohistochemistry
What is the role of the student?
- The student will observe the practical experiments but will be highly involved in the analysis of the results
- The tasks will be done under supervision
What are the tasks expected to be accomplished by the student?
The student will: 1. Conduct animal behavior testing; 2. Learn and prepare cell culture; 3. Use molecular biology techniques, including Polymerase Chain Reaction (PCR), Western blotting, and High-throughput Sequencing to study the effect of morphine on expression of inflammatory factors. 4. Observe the microenvironment of cells by flow cytometry and immunohistochemistry; Analyzing experiment results with one-way analysis of variance (ANOVA) by IBM SPSS ® Statistics 20 software. Graphs were generated using GraphPad Prism 7 or Origin 8.
Will there be any theoretical teaching provided (preliminary readings, lectures, courses, seminars etc)
There will be a seminar, provided by Prof. Tong Liu, once a week.
What is expected from the student at the end of the research exchange? What will be the general outcome of the student?
- The student will prepare a presentation
- The student will prepare a scientific report
What skills are required of the student? Is there any special knowledge or a certain level of studies needed?
The student should: 1. be hard-working, highly initiative, and have good skills in interpersonal communication and collaboration, critical and analytical thinking, and problem solving; have basic experiment skills, including PCR and Western Blot. Subjects passed: Neurobiology or neuroscience
 Previous experience with: Basic lab experiment
Are there any legal limitations in the student’s involvement
Type of students accepted
This project accepts:
- Medical students
- Graduated students (less than 6 months)
- Pre-Medical students from the American-British system
- Students in biomedical fields
- Guo R; Chen LH; Xing C; Liu T. Pain regulation by gut microbiota: molecular mechanisms and therapeutic potential. Br J Anaesth. 2019 Nov;123(5):637-654.