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Tetrandrine protects mouse retinal ganglion cells from ischemic injury
The brain is a delicate organ that the body has gone to great lengths to protect. However, in spite of this, it is not immune to damage either from injury or cell deterioration. Whenever the brain suffers a shock like this, cytosolic ionized calcium often increases within seconds or minutes and this triggers a series of chemical reactions within the brain that can include phospholipases, endonucleases, proteases, and protein kinases followed by both apoptotic and necrotic cell death of neurons, including retinal neurons. Trying to mitigate these effects and potential permanent damages on the brain has been the focus of researchers and drug developers for some time now. One possible therapy that is proposed and subsequently tested by Li et al. is tetrandine (Tet). This is a natural compound that is extracted from the root of the Chinese herb creeper Stephania tetrandra. It has been shown to be a calcium channel blocker that inhibits lipid peroxidation and the generation of reactive oxygen species. It can also suppress the production of cytokines and inflammatory mediators in the brain after ischemia reperfusion injury, anoxia or Alzheimer's Disease. Because of these properties, researchers were drawn to the idea of using Tet to determine its protective effects on retinal ganglion cells (RGCs).
To do this, Li and his team conducted a series of in vitro models of cell death including serum deprivation, glutamate and hydrogen peroxide treatment of RGC-5 cells, staurosporine (SSP)-induced RGC-5 cells, and purified RGCs in culture. What they found was that Tet was in fact effective in protecting RGCs one day after treatment, but after three days lost its effectiveness. They attributed this result to a metabolism that caused concentrations of Tet to drop below therapy levels. In order to further test the effectiveness of Tet, the researchers needed to monitor mitochondrial membrane potential within the retinal cells to gauge their resistance to the processes induced after injury. To do so they injected the cells with the fluorescent indicator JC-10™. The convenient loading was made possible through a streamlined protocol that makes it easy to accurately insert the dye exactly where it will be most capable of producing results. Additionally, with its improved solubility, JC-10™ is much less likely to be affected by aqueous solutions, which greater enhances its ability to deliver accurate readings.
The results obtained in this study offer some key insight into treatment options for retinal damage caused by brain injury or cell death. As seen in the study, obtaining results required accurate readings as the effect of Tet was time sensitive. The increased intensity and higher signal to background ratios of JC-10™ helped create clear images that easily identified the effect Tet was having on the cells being studied. Previous indicators presented a challenge because the greater possibility for interference, which obscured results and made it difficult to confidently attest to their significance. JC-10™ has helped overcome this and opened the door for further advancements in the field of therapeutic pharmacology.
To do this, Li and his team conducted a series of in vitro models of cell death including serum deprivation, glutamate and hydrogen peroxide treatment of RGC-5 cells, staurosporine (SSP)-induced RGC-5 cells, and purified RGCs in culture. What they found was that Tet was in fact effective in protecting RGCs one day after treatment, but after three days lost its effectiveness. They attributed this result to a metabolism that caused concentrations of Tet to drop below therapy levels. In order to further test the effectiveness of Tet, the researchers needed to monitor mitochondrial membrane potential within the retinal cells to gauge their resistance to the processes induced after injury. To do so they injected the cells with the fluorescent indicator JC-10™. The convenient loading was made possible through a streamlined protocol that makes it easy to accurately insert the dye exactly where it will be most capable of producing results. Additionally, with its improved solubility, JC-10™ is much less likely to be affected by aqueous solutions, which greater enhances its ability to deliver accurate readings.
The results obtained in this study offer some key insight into treatment options for retinal damage caused by brain injury or cell death. As seen in the study, obtaining results required accurate readings as the effect of Tet was time sensitive. The increased intensity and higher signal to background ratios of JC-10™ helped create clear images that easily identified the effect Tet was having on the cells being studied. Previous indicators presented a challenge because the greater possibility for interference, which obscured results and made it difficult to confidently attest to their significance. JC-10™ has helped overcome this and opened the door for further advancements in the field of therapeutic pharmacology.
References
- Li, Weiyi, et al. "Tetrandrine protects mouse retinal ganglion cells from ischemic injury." Drug Des Devel Ther 8 (2014): 327-339.
Original created on March 23, 2017, last updated on March 23, 2017
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