Intervention timing and effect of PJ34 on astrocytes during oxygen-glucose deprivation/reperfusion and cell death pathways.

Poly (ADP-ribose) polymerase-1 (PARP-1) plays as a double edged sword in cerebral ischemia-reperfusion, hinging on its effect on the intracellular energy storage and injury severity, and the prognosis has relationship with intervention timing. During ischemia injury, apoptosis and oncosis are the two main cell death pathway sin the ischemic core. The participation of astrocytes in ischemia-reperfusion induced cell death has triggered more and more attention. Here, we examined the protective effects and intervention timing of the PARP-1 inhibitor PJ34, by using a mixed oxygen-glucose deprivation/reperfusion (OGDR) model of primary rat astrocytes in vitro, which could mimic the ischemia-reperfusion damage in the "ischemic core". Meanwhile, cell death pathways of various PJ34 treated astrocytes were also investigated. Our results showed that PJ34 incubation (10 µmol/L) did not affect release of lactate dehydrogenase (LDH) from astrocytes and cell viability or survival 1 h after OGDR. Interestingly, after 3 or 5 h OGDR, PJ34 significantly reduced LDH release and percentage of PI-positive cells and increased cell viability, and simultaneously increased the caspase-dependent apoptotic rate. The intervention timing study demonstrated that an earlier and longer PJ34 intervention during reperfusion was associated with more apparent protective effects. In conclusion, earlier and longer PJ34 intervention provides remarkable protective effects for astrocytes in the "ischaemic core" mainly by reducing oncosis of the astrocytes, especially following serious OGDR damage.

Inordinate glucose variation poststroke is associated with poor neurological improvement in patients without history of diabetes.

INTRODUCTION: Glucose variation is an important risk factor for the complications of diabetes mellitus. The plasma glucose level poststroke is in continuous fluctuation. However, whether the variation influences neurological improvement remains unknown. AIMS: This observational study aimed to investigate the association of glucose variation with neurological improvement poststroke. METHODS: We consecutively enrolled 216 ischemic stroke patients with no history of diabetes mellitus within 72 h of onset, with instant blood glucose <11.1 mmol/L at admission. The glucometabolic status was evaluated by an oral glucose tolerance test 1 day after admission and 14 days after stroke, respectively. The severity of neurological deficit was assessed with the National Institute of Health Stroke Scale (NIHSS). RESULTS: Fourteen days after stroke, 31% patients were found to have impaired glucose tolerance and 30.6% were newly diagnosed diabetes mellitus by oral glucose tolerance test. A higher level of instant blood glucose at admission or fasting plasma glucose (FPG) at 1 day correlated with a less neurological improvement. The number of patients with no <20% decrease in NIHSS was significantly decreased in patient group with higher than 30% variation of either FPG or 2-h postprandial glucose. Similar correlation between glucose variation and neurological improvement was also found in 117 patients with 2-h postprandial glucose ≥7.8 mmol/L at 1 day. CONCLUSIONS: Inordinate glucose variation correlated with less neurological improvement poststroke, giving the evidence that the fluctuation of glucose levels in stroke patients should be taken into consideration during glucose modulation.