Stereological Study Reveals Neuron and Glia Proliferation in Hippocampus of Lithium-Treated Mice

Dentate gyruspilot

The optical fractionator probe was used to quantify the number of neurons and glia in the dentate gyrus

Doctors have used lithium to treat patients with bipolar disorder since the 1970s. Known for its efficacy in stabilizing patients’ moods by regulating manic episodes, lithium is also associated with a decreased risk of suicide. But while this naturally occurring element is the most widely prescribed medication for those suffering from bipolar disorder, scientists still have much to learn about how lithium physically affects the brain.

A recent study published in the journal Bipolar Disorders adds to the growing body of evidence that says lithium contributes to cell proliferation in parts of the brain. Conducted by scientists at the University of Mississippi and the VU University Medical Center in Amsterdam, the study revealed an increased number of neurons and glia, and increased astrocyte density in the dentate gyrus of lithium-treated mice versus controls treated with a placebo.

Using the optical fractionator probe in Stereo Investigator, the researchers quantified the number of Nissl stained neurons and glial cells, and calculated astrocyte density. The results showed twenty-five percent more neurons and twenty-one percent more glia in the denate gyrus of lithium-treated mice. They also performed a stereological examination of another brain region – the medial prefrontal cortex (mPFC), but did not witness significant differences between lithium-treated and control mice in this area.

“In this study, particular cortical regions, ie. the fascia dentata in the hippocampus and the mPFC in the cerebral cortex needed to be selected in histological sections of the mice brains,” explained Dr. Harry B.M. Uylings, “therefore the stereological counting procedure applied was the best one. Stereo Investigator greatly assisted in the counting of cells, and the software’s excel data-output was especially beneficial.”

According to the paper, the findings present a more detailed picture of lithium-induced alterations in the dentate gyrus cellular phenotype than previously available, and provide the first evidence for lithium-induced increases in glia and astrocytes.

The authors also explain that while cell number increased in the dentate gyrus of lithium-treated mice, the region’s overall volume as well as that of the greater hippocampus was unaffected by the element. The volume of the dentate gyrus and the hippocampus as a whole was measured with the Cavalieri method in Stereo Investigator.  The researchers describe the dissociation between cell proliferation and volume as “an interesting observation that warrants further investigation.”

Rajkowska, G., Clarke, G., Mahajan, G., Licht, C.M., van de Werd, H.J., Yuan, P., Stockmeier, C.A., Maji, H.K., Uylings, H.B., Differential effect of lithium on cell number in the hippocampus and prefrontal cortex in adult mice: a stereological study. Bipolar Disord. 2016 Feb;18(1):41-51. doi: 10.1111/bdi.12364.

Exercise Heals the Brain After Binge Drinking

The granule cell layer of the dentate gyrus captured using a 100x objective. Image provided by Mark Maynard.

The granule cell layer of the dentate gyrus. Image provided by Mark Maynard.

Binge drinking damages brain regions responsible for memory, decision-making, and behavioral control. After a binge, the brain begins to heal itself but not much is known about this self-repair process. In a study published in PLoS ONE, researchers used rats to find that binge drinking damages the hippocampus, and exercise reverses this damage.

The study found that excessive ethanol killed granule neurons in the dentate gyrus (DG), a part of the hippocampus, and significantly decreased the volume of the DG. Rats that exercised after binging had more DG granule neurons and a larger DG than rats that did not exercise after a binge. In fact, rats that exercised after binging had a similar number of DG neurons and a similar DG volume to that of controls, indicating that exercise almost fully reversed damaged to the DG caused by binge drinking.

Continue reading “Exercise Heals the Brain After Binge Drinking” »

Scientists use Stereo Investigator to Discover that Part of the Hippocampus Shrinks in Socially Isolated Rodents

Scientists studied cresyl-violet stained sections of the left brain hemispheres of isolated and group-housed rodents.

Scientists studied cresyl-violet stained sections of the left brain hemispheres of isolated and group-housed rodents. Image courtesy of the Venero Lab at The National University of Distance Education in Madrid, Spain.

Social isolation is stressful. Scientists have known it for decades. They also know that isolation causes changes to occur in the brains of rodents and primates. But most studies examine the effects of isolation during childhood; and the ones that do focus on adulthood tend to use male subjects. For the first time, researchers in Spain show that long-term social isolation causes part of the brain to shrink in the adult female degu, a highly social rat-like animal native to South America.

Continue reading “Scientists use Stereo Investigator to Discover that Part of the Hippocampus Shrinks in Socially Isolated Rodents” »

Researchers at Stanford use confocal stereology to study neurodevelopment

A Stereo Investigator system for confocal stereology was installed in Dr. Michelle Monje’s lab in the Department of Neurology and Neurological Sciences at Stanford University School of Medicine. Dr. Monje and her lab members will use the system to investigate the molecular and cellular mechanisms of postnatal neurodevelopment.

Dr. Julie Korich, staff scientist at MBF, installed Stereo Investigator on a Zeiss laser scanning confocal microscope and trained the lab members on how to use the system.

From top left: Chris Mount, Grant Lin, Ingrid Inpma, David Purger From bottom left: Elizabeth Qin, Viola Caretti, Lauren Wood

From top left: Chris Mount, Grant Lin, Ingrid Inpma, David Purger
From bottom left: Elizabeth Qin, Viola Caretti, Lauren Wood

During the training, Dr. Korich discussed how Stereo Investigator integrates with Zeiss’ microscope software, explained the Cavalieri probe for estimating regional volume, and showed the lab how to use Stereo Investigator to collect confocal image stacks in the systematic and random way that’s necessary for unbiased stereology. She also explained how to count cells from those image stacks and from 3D virtual slides with Stereo Investigator on a computer away from the microscope.

Click here to learn more about how researchers are using Stereo Investigator in their labs.

Stereo Investigator Helps Scientists Assess Damage in Rat Model of Ischemic Stroke

iStock_mri_scanl

A stroke patient is rushed to the hospital. Deprived of oxygen-rich blood, brain cells have already died, and more damage will probably occur in the hours and days to come. But researchers at the University of South Florida and the University of Padova in Italy say a two-part package administered through the body, rather than directly into the brain, may be the key to staving off some of the cell death that takes place after a stroke.

In their study, published in the Journal of Enzyme Inhibition and Medicinal Chemistry, the scientists saw a smaller region of damage in a rat model of focal cerebral ischemia, when the rats were treated with a combination of an anesthetic and a Caspase-3 inhibitor – a drug that suppresses a protein involved in brain cell death.

Continue reading “Stereo Investigator Helps Scientists Assess Damage in Rat Model of Ischemic Stroke” »

Florida Researchers Study Traumatic Brain Injury With Stereo Investigator

journal.pone.0053376.g003

Figure 3 from “Hippocampal CA3 cell loss and downregulation of cell proliferation.”

If a head gets hit hard enough, the trauma occurs instantly. Neurons die, the brain swells as microglia cells rush to the damaged area, and the protective armor known as the blood brain barrier might even rupture. But it doesn’t end there. Long term effects include cognitive impairment, loss of sensory processing, and susceptibility to neurodegenerative diseases like Alzheimer’s.

Researchers at the University of South Florida say patients suffering from chronic Traumatic Brain Injury (TBI) experience a “cascade of events” marked by long-term neuroinflammation, cell loss, and impaired cell proliferation that may manifest over time.

“While TBI is generally considered an acute injury, a chronic secondary cell death perturbation (i.e., neuroinflammation) and a diminished endogenous repair mechanism (i.e., cell proliferation) accompany the disease pathology over long-term,” the authors say in their paper published this month in PLOS ONE.

The scientists used unbiased stereology to analyze activated microglia cells, cell proliferation, and differentiation into immature neurons in several regions of the brains of rats which had experienced TBI eight weeks prior.

They used Stereo Investigator with the Cavalieri estimator probe and the optical fractionator probe to estimate the quantity and volume of stained cells in the cortex, striatum, thalamus, fornix, cerebral peduncle, and corpus callosum, as well as the subgranular zone and the subventricular zone in both hemispheres of the brain.

Eight weeks after the TBI occurred, the researchers found an increased level of active microglia cells at the direct site of the TBI as well as surrounding regions. They also report a decrease in hippocampal neurons, and low levels of cell proliferation in the neurogenic niches.

“Our overarching theme advances the concept that a massive neuroinflammation after TBI represents a second wave of cell death that impairs the proliferative capacity of cells, and impedes the regenerative capacity of neurogenesis in chronic TBI,” the authors say in their paper.

They go on to suggest a “multi-pronged treatment targeting inflammatory and cell proliferative pathways” may help alleviate the pathological effects of chronic TBI.

Read the full paper “Long-Term Up-regulation of Inflammation and Suppression of Cell Proliferation in the Brain of Adult Rats Exposed to Traumatic Brain Injury Using the Controlled Cortical Impact Model” on PLOS ONE.

{Acosta S.A., Tajiri N., Shinozuka K., Ishikawa H., Grimmig B., et al. (2013). Long-Term Up-regulation of Inflammation and Suppression of Cell Proliferation in the Brain of Adult Rats Exposed to Traumatic Brain Injury Using the Controlled Cortical Impact Model. PLoS ONE 8(1): e53376. doi:10.1371/journal.pone.0053376}

To stay updated on MBF Bioscience company and customer news, “like” us on Facebook and follow us on Twitter.