Cell death: physiopathological and therapeutic implications

Potential neuroprotection of protodioscin against cerebral ischemia-reperfusion injury in rats through intervening inflammation and apoptosis

The aim of the current research is to investigate the cerebral-protection of protodioscin on a transient cerebral ischemia-reperfusion (I/R) model and to explore its possible underlying mechanisms. The rats were preconditioned with protodioscin at the doses of 25 and 50mgkg(-1) prior to surgery. Then the animals were subjected to right middle cerebral artery occlusion (MCAO) using an intraluminal method by inserting a thread (90min surgery). After the blood flow was restored in 24h via withdrawing the thread, some representative indicators for the cerebral injury were evaluated by various methods including TTC-staining, TUNEL, immunohistochemistry, and Western blotting. As compared with the operated rats without drug intervening, treatment with protodioscin apparently lowered the death rate and improved motor coordination abilities through reducing the deficit scores and cerebral infarct volume. What's more, an apparent decrease in neuron apoptosis detected in hippocampus CA1 and cortex of the ipsilateral hemisphere might attribute to alleviate the increase in Caspase-3 and Bax/Bcl-2 ratio. Meanwhile, concentrations of several main pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) in the serum were also significantly suppressed. Finally, the NF-κB and IκBa protein expressions in the cytoplasm of right injured brain were remarkably up-regulated, while NF-κB in nucleus was down-regulated. Therefore, these observed findings demonstrated that protodioscin appeared to reveal potential neuroprotection against the I/R injury due to its anti-inflammatory and anti-apoptosis properties. This therapeutic effect was probably mediated by the inactivation of NF-κB signal pathways.

The role of aquaporin 4 in apoptosis after intracerebral hemorrhage

Background

We previously reported that aquaporin-4 deletion (AQP4^−/−) in mice increased edema and altered blood-brain barrier integrity following intracerebral hemorrhage (ICH). To date, little is known about the role of AQP4 in apoptosis after ICH. The purpose of this study was to examine the role of AQP4 in apoptosis and its mechanisms after ICH using AQP4^−/− mice.

Methods

We compared the survival rate and neurological deficits in wild-type (AQP4^+/+) mice with those in AQP4^−/− mice following ICH. Histological changes were detected with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining and Hoechst staining. The cell types involved were determined by immunocytochemical studies. We also measured activated caspase-3, caspase-9, caspase-8, Bax, and Bcl-2 with Western blotting at 1, 3, and 7 days after ICH. A cytokine protein assay was used to detect cytokines in AQP4^+/+ and AQP4^−/− mice following ICH, and the results were verified by ELISA.

Results

We found more apoptotic cells in AQP4^−/− mice following ICH; the cell types involved were predominantly neurons and astrocytes. Western blotting showed that the expression of activated caspase-3 and caspase-8 was significantly increased (P <0.05). Moreover, we demonstrated a greater enhancement in the release of TNF-α and IL-1β, as well as their receptors, in AQP4^−/− mice following ICH than in AQP4^+/+ mice by cytokine protein assay and Western blotting (P <0.05). The inhibitors of TNF-α and IL-1β reduced apoptotic cells after ICH in AQP4^−/− mice compared with wild-type mice (P <0.05).

Conclusions

AQP4 deletion increases apoptosis following ICH, and the underlying mechanism may be through cytokines, especially TNF-α and IL-1β, initiating the apoptotic cascade, as well as activation of caspase-3 and caspase-8.

An-Gong-Niu-Huang Wan protects against cerebral ischemia induced apoptosis in rats: up-regulation of Bcl-2 and down-regulation of Bax and caspase-3

ETHNOPHARMACOLOGICAL RELEVANCE

The An-Gong-Niu-Huang Wan (AGNH), a Chinese traditional medicine, has been used for treatment of cerebral diseases for centuries in China and other Asian countries, and is approved by the State Food and Drug Administration of China for the treatment of stroke. The aim of present study is to test the neuroprotective effects of AGNH on cerebral ischemia in rats and to explore the underlying mechanisms.

MATERIALS AND METHODS

75 Male Sprague-Dawley rats were randomly divided into 5 groups: sham, ischemia-reperfusion (I/R), and I/R plus 0.065 g/kg/d AGNH, 0.125 g/kg/d AGNH and 0.25 g/kg/d AGNH. Cerebral ischemia was induced by 1.5h of middle cerebral artery occlusion (MCAO). Neurological functional deficits were evaluated according to Zea longa׳s score, cerebral infarct area was measured by tetrazolium staining. Cell injury and apoptosis were assessed by Nissl staining and DNA fragmentation assay. The expression of Bax, Bcl-2 and caspase-3 were analyzed by Western blot.

RESULTS

Rats subjected to MCAO exhibited worsened neurological score, infarct area, cell damage and apoptosis. These were all attenuated by AGNH (0.125 and 0.25 g/kg/d). Moreover, AGNH reversed cerebral ischemia induced decreases in Bcl-2 expression and increases in Bax and caspase-3 expression.

CONCLUSIONS

These results suggest that AGNH exerts neuroprotective effects, and the neuroprotection is likely to relate to depressed Bax/Bcl-2 ratio and caspase-3 level, leading to inhibition of apoptotic cell death.

Gc protein-derived macrophage-activating factor (GcMAF) stimulates cAMP formation in human mononuclear cells and inhibits angiogenesis in chick embryo chorionallantoic membrane assay

The effects of Gc protein-derived macrophage-activating factor (GcMAF) have been studied in cancer and other conditions where angiogenesis is deregulated. In this study, we demonstrate for the first time that the mitogenic response of human peripheral blood mononuclear cells (PBMCs) to GcMAF was associated with 3'-5'-cyclic adenosine monophosphate (cAMP) formation. The effect was dose dependent, and maximal stimulation was achieved using 0.1 ng/ml. Heparin inhibited the stimulatory effect of GcMAF on PBMCs. In addition, we demonstrate that GcMAF (1 ng/ml) inhibited prostaglandin E(1)- and human breast cancer cell-stimulated angiogenesis in chick embryo chorionallantoic membrane (CAM) assay. Finally, we tested different GcMAF preparations on CAM, and the assay proved to be a reliable, reproducible and inexpensive method to determine the relative potencies of different preparations and their stability; we observed that storage at room temperature for 15 days decreased GcMAF potency by about 50%. These data could prove useful for upcoming clinical trials on GcMAF.