4-Hydroxy TEMPO Attenuates Dichlorvos Induced Microglial Activation and Apoptosis

Abstract

Microglial cells have been implicated in various neurodegenerative diseases. Previous studies from our lab have shown that dichlorvos (an organophosphate) could induce Parkinson's like features in rats. Recently, we have shown that dichlorvos can induce microglial activation, and if not checked in time could ultimately induce neuronal apoptosis. However, this activation does not always pose a threat to the neurons. Activated microglia also secrete various neuronal growth factors, suggesting that they have beneficial roles in CNS repair. Therefore, it is essential to control their detrimental functions selectively. Here, we tried to find out how microglial cells behave when exposed to dichlorvos in either the presence or absence of potent nitric oxide scavenger and superoxide dismutase mimetic, 4-hydroxy TEMPO (4-HT). Wistar rat pups (1 day) were used to isolate and culture primary microglial cells. We found 4-HT pretreatment successfully attenuated the dichlorvos mediated microglial activation. Moreover, 4-HT pretreatment decreased the up-regulated levels of p53 and its downstream effector, p21. The expression of various cell cycle regulators such as Chk2, CDC25a, and cyclin A remained close to their basal levels when 4-HT pretreatment was given. DNA fragmentation analysis showed significant reduction in the DNA damage of 4-HT pretreated microglia as compared to dichlorvos treated cells. In addition to this, we found 4-HT pretreatment prevented the microglial cells from undergoing apoptotic cell death even after 48 h of dichlorvos exposure. Taken together, our results showed 4-HT pretreatment could successfully ameliorate the dichlorvos induced microglial cell damage.

Status of Neuropharmacology Research in India

“…To achieve this, a potent NO scavenger and SOD (superoxide dismutase) mimetic, 4-hydroxy TEMPO (4-HT) was investigated. DNA fragmentation analysis showed significant reduction in the DNA damage of 4-HT pre-treated microglia as compared to dichlorvos treated cells (Sunkaria et al, 2014a).…”

Dihydroxycoumarins as highly selective fluorescent probes for the fast detection of 4-hydroxy-TEMPO in aqueous solution

“…Although the studies have not been performed in living cells, the probe has the potential application for the fast detection of 4-hydroxy-TEMPO in biological media since the concentrations of 4-hydroxy-TEMPO used in biological experiments are in the range 50 mM to 4 mM. 39,40 The biological signicance of this work is proven by the fact that 4hydroxy-TEMPO is used as a scavenger for different radicals. Its detection and quantitative determination under physiological conditions might help to understand the mechanism of oxidative stress.…”