Toad venom: A comprehensive review of chemical constituents, anticancer activities, and mechanisms.

Toad venom, a traditional natural medicine, has been used for hundreds of years in China for treating different diseases. Many studies have been performed to elucidate the cardiotonic and analgesic activities of toad venom. Until the last decade, an increasing number of studies have documented that toad venom is a source of lead compound(s) for the development of potential cancer treatment drugs. Research has shown that toad venom contains 96 types of bufadienolide monomers and 23 types of indole alkaloids, such as bufalin, cinobufagin, arenobufagin, and resibufogenin, which exhibit a wide range of anticancer activities in vitro and, in particular, in vivo for a range of cancers. The main antitumor mechanisms are likely to be apoptosis or/and autophagy induction, cell cycle arrest, cell metastasis suppression, reversal of drug resistance, or growth inhibition of cancer cells. This review summarizes the chemical constituents of toad venom, analyzing their anticancer activities and molecular mechanisms for cancer treatments. We also outline the importance of further studies regarding the material basis and anticancer mechanisms of toad venom.

The detection methods currently available for protein aggregation in neurological diseases.

Protein aggregation is a pathological feature in various neurodegenerative diseases and is thought to play a crucial role in the onset and progression of neurological disorders. This pathological phenomenon has attracted increasing attention from researchers, but the underlying mechanism has not been fully elucidated yet. Researchers are increasingly interested in identifying chemicals or methods that can effectively detect protein aggregation or maintain protein stability to prevent aggregation formation. To date, several methods are available for detecting protein aggregates, including fluorescence correlation spectroscopy, electron microscopy, and molecular detection methods. Unfortunately, there is still a lack of methods to observe protein aggregation in situ under a microscope. This article reviews the two main aspects of protein aggregation: the mechanisms and detection methods of protein aggregation. The aim is to provide clues for the development of new methods to study this pathological phenomenon.

A novel detection method for neuronal death indicates abnormalities in intracellular membranous components in neuronal cells that underwent delayed death.

Acute neuronal degeneration is always preceded under the light and electron microscopes by a stage called microvacuolation, which is characterized by a finely vacuolar alteration in the cytoplasm of the neurons destined to death. In this study, we reported a method for detecting neuronal death using two membrane-bound dyes, rhodamine R6 and DiOC6(3), which may be associated with the so-called microvacuolation. This new method produced a spatiotemporally similar staining pattern to Fluoro-Jade B in kainic acid-damaged brains in mice. Further experiments showed that increased staining of rhodamine R6 and DiOC6(3) was observed only in degenerated neurons, but not in glia, erythrocytes, or meninges. Different from Fluoro-Jade-related dyes, rhodamine R6 and DiOC6(3) staining is highly sensitive to solvent extraction and detergent exposure. Staining with Nile red for phospholipids and filipin III for non-esterified cholesterol supports that the increased staining of rhodamine R6 and DiOC6(3) might be associated with increased levels of phospholipids and free cholesterol in the perinuclear cytoplasm of damaged neurons. In addition to kainic acid-injected neuronal death, rhodamine R6 and DiOC6(3) were similarly useful for detecting neuronal death in ischemic models either in vivo or in vitro. As far as we know, the staining with rhodamine R6 or DiOC6(3) is one of a few histochemical methods for detecting neuronal death whose target molecules have been well defined and therefore may be useful for explaining experimental results as well as exploring the mechanisms of neuronal death.

Different changes in pre- and postsynaptic components in the hippocampal CA1 subfield after transient global cerebral ischemia.

To date, ischemia-induced damage to dendritic spines has attracted considerable attention, while the possible effects of ischemia on presynaptic components has received relatively less attention. To further examine ischemia-induced changes in pre- and postsynaptic specializations in the hippocampal CA1 subfield, we modeled global cerebral ischemia with two-stage 4-vessel-occlusion in rats, and found that three postsynaptic markers, microtubule-associated protein 2 (MAP2), postsynaptic density protein 95 (PSD95), and filamentous F-actin (F-actin), were all substantially decreased in the CA1 subfield after ischemia/reperfusion (I/R). Although no significant change was detected in synapsin I, a presynaptic marker, in the CA1 subfield at the protein level, confocal microscopy revealed that the number and size of synapsin I puncta were significantly changed in the CA1 stratum radiatum after I/R. The size of synapsin I puncta became slightly, but significantly reduced on Day 1.5 after I/R. From Days 2 to 7 after I/R, the number of synapsin I puncta became moderately decreased, while the size of synapsin I puncta was significantly increased. Interestingly, some enlarged puncta of synapsin I were observed in close proximity to the dendritic shafts of CA1 pyramidal cells. Due to the more substantial decrease in the number of F-actin puncta, the ratio of synapsin I/F-actin puncta was significantly increased after I/R. The decrease in synapsin I puncta size in the early stage of I/R may be the result of excessive neurotransmitter release due to I/R-induced hyperexcitability in CA3 pyramidal cells, while the increase in synapsin I puncta in the later stage of I/R may reflect a disability of synaptic vesicle release due to the loss of postsynaptic contacts.