सेरेब्रल रक्त oxygenation phosphorescence के आक्सीजन पर निर्भर शमन के आधार पर मापन
Summary
हम phosphorescence की ऑक्सीजन पर निर्भर शमन पर आधारित मस्तिष्क vasculature में ऑक्सीजन की आंशिक दबाव (pO2) को मापने के लिए एक प्रयोगात्मक प्रक्रिया मौजूद है. पशु तैयारी और इमेजिंग प्रक्रियाओं दोनों चूहों में देखने सीसीडी आधारित pO2 की इमेजिंग के बड़े क्षेत्र और pO2 चूहों में उत्तेजना 2-photon आधारित इमेजिंग के लिए उल्लिखित थे.
Abstract
Monitoring of the spatiotemporal characteristics of cerebral blood and tissue oxygenation is crucial for better understanding of the neuro-metabolic-vascular relationship. Development of new pO2 measurement modalities with simultaneous monitoring of pO2 in larger fields of view with higher spatial and/or temporal resolution will enable greater insight into the functioning of the normal brain and will also have significant impact on diagnosis and treatment of neurovascular diseases such as stroke, Alzheimer’s disease, and head injury.
Optical imaging modalities have shown a great potential to provide high spatiotemporal resolution and quantitative imaging of pO2 based on hemoglobin absorption in visible and near infrared range of optical spectrum. However, multispectral measurement of cerebral blood oxygenation relies on photon migration through the highly scattering brain tissue. Estimation and modeling of tissue optical parameters, which may undergo dynamic changes during the experiment, is typically required for accurate estimation of blood oxygenation. On the other hand, estimation of the partial pressure of oxygen (pO2) based on oxygen-dependent quenching of phosphorescence should not be significantly affected by the changes in the optical parameters of the tissue and provides an absolute measure of pO2. Experimental systems that utilize oxygen-sensitive dyes have been demonstrated in in vivo studies of the perfused tissue as well as for monitoring the oxygen content in tissue cultures, showing that phosphorescence quenching is a potent technology capable of accurate oxygen imaging in the physiological pO2 range.
Here we demonstrate with two different imaging modalities how to perform measurement of pO2 in cortical vasculature based on phosphorescence lifetime imaging. In first demonstration we present wide field of view imaging of pO2 at the cortical surface of a rat. This imaging modality has relatively simple experimental setup based on a CCD camera and a pulsed green laser. An example of monitoring the cortical spreading depression based on phosphorescence lifetime of Oxyphor R3 dye was presented. In second demonstration we present a high resolution two-photon pO2 imaging in cortical micro vasculature of a mouse. The experimental setup includes a custom built 2-photon microscope with femtosecond laser, electro-optic modulator, and photon-counting photo multiplier tube. We present an example of imaging the pO2 heterogeneity in the cortical microvasculature including capillaries, using a novel PtP-C343 dye with enhanced 2-photon excitation cross section.
Click here to view the related article Synthesis and Calibration of Phosphorescent Nanoprobes for Oxygen Imaging in Biological Systems.
Protocol
Discussion
हम pO2 cortical microvasculature में माप phosphorescence की ऑक्सीजन पर निर्भर शमन पर आधारित दो अनुप्रयोगों का प्रदर्शन किया. जबकि पहले सीसीडी इमेजिंग के आधार पर विधि pO2 के दृश्य निगरानी की व्यापक क्षेत्र प्रदान करता है, cortical microvasculature म?…
Acknowledgements
हम स्वास्थ्य R01NS057476 अनुदान, P50NS010828, P01NS055104, R01EB000790, K99NS067050, R01HL081273 और R01EB007279 और अमेरिकन हार्ट एसोसिएशन अनुदान 0855772D के अमेरिकी राष्ट्रीय संस्थानों से समर्थन स्वीकार करना चाहते हैं.
Materials
| Material Name | Type | Company | Catalogue Number | Comment |
|---|---|---|---|---|
| Glycopyrrolate | Reagent | American Regent Inc. | NDC 0517-4605-25 | Used to control pharyngeal, tracheal, and bronchial secretions. |
| Lidocaine HCL | Reagent | Hospira Inc. | NDC 0409-4277-01 | Used as the local anesthesia during surgeries. |
| Isoflurane | Reagent | Baxter Healthcare Corp. | NDC 10019-360-40 | Used as a general inhalation anesthetic drug during surgeries and as a general anesthesia during experiments with mice. |
| Alpha Chloralose | Reagent | Sigma | C0128 | Used as a general anesthesia during experiments with rats. |
| Fluorescein isothio-cyanate–dextran | Reagent | Sigma | FD2000S | Administrated to create ~ 500 nM concentration in blood. |
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