Biochemical Assays and Histological Analysis in Animal Models of Stroke
At a glance
For stroke drugs, the pharmacokinetics and pharmacodynamics of drug candidates are key to determining whether they can treat a disease. Biochemical tests and histology are valuable adjuncts in this effort, especially if combined with in vivo and ex vivo experiments. Such a comprehensive method allows scientists to characterize candidate drugs and measure how they alter metabolic molecules and tissues in living organisms.
Fig.1. Rat brain histology examination. (Luo, et al., 2023)
Ace Therapeutics provides a large range of biochemical assays and histology analyses to evaluate the efficacy of stroke drugs.
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Biochemical Assays in Animal Models of Stroke
A biochemical assay is a method used to evaluate the activity of biological molecules or the functions of cells. In the context of stroke research, these assays help assess molecular changes in the brain and other tissues, providing insight into the extent of injury and the underlying pathology of stroke.
In recent years, a large variety of enzyme/biochemical assays have been developed to discover and optimize compounds that inhibit the activity of targets for stroke. Several key biochemical markers are commonly measured in stroke research:
- Lactate dehydrogenase (LDH). In serum or cerebrospinal fluid, high levels of LDH indicate cellular damage and are often used to indicate tissue damage.
- Brain-derived neurotrophic factor (BDNF). Neuronal survival and recovery depend on BDNF. The level of BDNF in the brain can indicate whether the brain is capable of recovering after a stroke when it changes.
- Inflammatory cytokines. Cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) are important in the inflammatory response that follows a stroke. Measuring these markers can provide insights into the severity of inflammation and potential therapeutic targets.
- Oxidative stress markers. Measurements of reactive oxygen species (ROS) and antioxidant enzymes can be used to assess oxidative stress in the brain, a leading cause of strokes.
| Biochemical Techniques | Description |
|---|---|
| Enzyme-Linked Immunosorbent Assay (ELISA) | ELISA is widely used to quantify inflammatory cytokines and neurotrophic factors in blood or brain tissue. |
| Western Blotting | This technique allows to detect and quantify specific proteins in a sample, providing insights into the molecular changes associated with stroke. |
| Polymerase Chain Reaction (PCR) | PCR allows to quantify the expression levels of specific genes involved in the pathophysiology of stroke, such as those related to inflammation, apoptosis, and neuroprotection. |
| Colorimetric Assays | These assays are simple and rapid, often used to measure enzyme activities or metabolites indicative of oxidative stress or cellular damage. |
Histological Analysis in Animal Models of Stroke
Histology is the study of tissue samples, to observe the microscopic anatomy and cellular remodeling of tissue affected by disease processes such as stroke. Scientists can show and measure the physical and structural change in brain tissue after a stroke using specific staining and imaging methods. Histology can reveal many things about stroke pathology:
- Cellular loss and death. Through histology, it is possible to determine how many neurons have been lost and how much cell damage has been done in different brain areas following a stroke.
- Inflammatory response. Inflammation is explained through histology (elevated immune cells, activation of glia, changes in cytokine expression) to help explain stroke.
- Tissue repair and regeneration. Examining neurotrophic factor expression and proliferation of neural progenitor cells, histology can quantify how much recovery is occurring in the brain after stroke.
- Ischemic penumbra and core. Histology can help to separate the ischemic core from the penumbra, which could be applied to the therapeutic interventions that will maintain brain function.
| Histological Techniques | Description |
|---|---|
| Hematoxylin and Eosin (HE) Staining | This common staining procedure permits analysis of tissue structure and cellular form. It reveals necrosis, odema and inflammation. |
| Immunohistochemistry (IHC) | It is useful for monitoring the expression of markers of neuroinflammation, apoptosis, and survival of neurons. |
| Nissl Staining | This method highlights neuronal cell bodies and is used to assess neuronal integrity and density in different brain regions where stroke occurs. |
| TUNEL Assay | This method detects apoptotic cells by labeling DNA fragments, allowing researchers to quantify the extent of programmed cell death following a stroke. |
| Fluorescent Microscopy | Advanced imaging techniques, including confocal microscopy, enable detailed examination of cellular interactions and the localization of specific molecules within tissues. |
- Luo, Y., et al. (2023). Human Serum Albumin-enriched Clopidogrel Bisulfate Nanoparticle Alleviates Cerebral Ischemia–Reperfusion Injury in Rats. Pharmaceutical Research, 40(7), 1821-1833.
