[Antisense oligodeoxynucleotides of glial glutamate transporter-1 inhibits the neuro-protection of cerebral ischemic preconditioning in rats].

The present study was undertaken to investigate the role of glial glutamate transporter-1 (GLT-1) in the brain ischemic tolerance induced by cerebral ischemic preconditioning (CIP) by observing the effect of GLT-1 antisense oligodeoxynucleotides (AS-ODNs) on the neuro-protection of CIP against brain ischemic insult in rats. Wistar rats with permanently occluded bilateral vertebral arteries were randomly assigned to 7 groups: (1) Sham group: the bilateral common carotid arteries (BCCA) were separated, but without occluding the blood flow; (2) CIP group: the BCCA were clamped for 3 min; (3) Brain ischemic insult group: the BCCA were clamped for 8 min; (4) CIP+brain ischemic insult group: 3 min CIP was preformed 2 d prior to 8 min ischemic insult; (5) Double distilled water group: 5 muL double distilled water was injected into the right lateral cerebral ventricle 12 h before, 12 h and 36 h after the BCCA was separated (but without occluding the blood flow), respectively; (6) AS-ODNs group: 5 microL AS-ODNs solution was injected into the right lateral cerebral ventricle 12 h before, 12 h and 36 h after the BCCA was separated (but without occluding the blood flow), respectively. This group was further divided into 9 nmol and 18 nmol subgroups according to the doses of AS-ODNs; (7) AS-ODNs+CIP+brain ischemic insult group: 5 microL AS-ODNs solution was injected into the right lateral cerebral ventricle 12 h before, 12 h and 36 h after CIP, respectively. This group was also further divided into 9 nmol and 18 nmol subgroups according to the doses of AS-ODNs. The other treatments were the same as those in CIP+brain ischemic insult group. The effect of the AS-ODNs on the expression of GLT-1 was assayed by using Western blot analysis. The profile of delayed neuronal death (DND) of pyramidal neurons in the CA1 hippocampus was evaluated by using thionin staining under light microscope by determining the neuronal density (ND) and histological grade (HG). Western blot analysis showed that AS-ODNs injected into the lateral cerebroventricle inhibited the expression of GLT-1 in the CA1 hippocampus in a dose-dependent manner. Neuropathological evaluation showed that there was no apparent DND in sham and CIP groups. Obvious DND of pyramidal neurons was found in brain ischemic insult group, which was represented by an increase in HG and a decrease in ND. CIP effectively protected the pyramidal neurons in the CA1 hippocampus against DND normally induced by ischemic insult, which indicating that CIP induced ischemic tolerance on the pyramidal neurons in the CA1 hippocampus. However, the injection of AS-ODNs into the lateral cerebroventricle blocked the neuro-protection of CIP against DND induced by brain ischemic insult. These results further proved the role of GLT-1 in the brain ischemic tolerance induced by CIP in rats.

The upregulation of glial glutamate transporter-1 participates in the induction of brain ischemic tolerance in rats.

Glial glutamate transporter-1 (GLT-1) plays an essential role in removing glutamate from the extracellular space and maintaining the glutamate below neurotoxic level in the brain. To explore whether GLT-1 plays a role in the acquisition of brain ischemic tolerance (BIT) induced by cerebral ischemic preconditioning (CIP), the present study was undertaken to observe in vivo changes in the expression of GLT-1 and glial fibrillary acidic protein (GFAP) in the CA1 hippocampus during the induction of BIT, and the effect of dihydrokainate (DHK), an inhibitor of GLT-1, on the acquisition of BIT in rats. Immunohistochemistry for GFAP showed that the processes of astrocytes were prolonged after a CIP 2 days before the lethal ischemic insult, which could protect pyramidal neurons in the CA1 hippocampus against delayed neuronal death induced normally by lethal ischemic insult. The prolonged processes extended into the area between the pyramidal neurons and tightly surrounded them. These changes made the pyramidal layer look like a 'shape grid'. Simultaneously, the prolonged and extended processes showed a great deal of GLT-1. Western blotting analysis showed significant upregulation of GLT-1 expression after the CIP, especially when it was administered 2 days before the subsequent lethal ischemic insult. Neuropathological evaluation by thionin staining showed that DHK dose-dependently blocked the protective role of CIP against delayed neuronal death induced normally by lethal brain ischemia. It might be concluded that the surrounding of pyramidal neurons by astrocytes and upregulation of GLT-1 induced by CIP played an important role in the acquisition of the BIT induced by CIP.

PPM1D as a novel biomarker for prostate cancer after radical prostatectomy.

Protein phosphatase magnesium-dependent 1 delta (PPM1D) is involved in several types of cancer. The current study examined the role of PPM1D expression in prostate cancer (PCa) tissues and in PCa cell lines. Expression of PPM1D was evaluated using immunohistochemistry in 234 PCa tissues after radical prostatectomy and 80 benign prostatic hyperplasia (BPH) tissues. The associations of PPM1D expression with clinicopathological parameters and survival were analyzed. In vitro, tumor cells were transfected with small interfering RNA targeting PPM1D (siPPM1D) or si-Scramble, and the cell proliferation, migration and invasion were determined. We found that PPM1D expression was significantly higher in PCa tissues than that in BPH tissues. PPM1D expression was positively correlated with Gleason score (p=0.022), T stage (p=0.015) and lymph node status (p=0.016). Kaplan-Meier curve analysis showed that patients with positive PPM1D expression had shorter biochemical recurrence-free survival and overall survival. Furthermore, multivariate analyses showed that PPM1D expression was an independent predictor of both biochemical recurrence-free (hazard ratio=3.437, 95% confidence interval=1.154-6.209, p=0.016) and overall survival (hazard ratio=5.026, 95% confidence interval=2.545-8.109, p=0.007). Knockdown of PPM1D inhibited the proliferation, migration and invasion capabilities of PC-3 and LNCaP cells. PPM1D expression may predict for both overall and biochemical recurrence-free survival in patients after radical prostatectomy for PCa. Elevated PPM1D expression plays a key role in progression of PCa.

[The prior occlusion of bilateral vertebral arteries during producing global cerebral ischemic damage model may play a protective role as preconditioning].

AIM: To study the effect of different intervals between occlusions of vertebral arteries and bilateral common carotid arteries on the Pulsinelli 4-vessel occlusion global cerebral ischemic model, and the features of ischemia of the brainstem and hippocampus induced by occulusion of bilateral common carotid arteries under the condition of occlusion of unilateral vertebral artery. METHODS: Eighty four adult male Wistar rats were divided into 4 groups randomly: control group, bilateral vertebral artery occluding group, global brain ischemic insult group, and unilateral vertebral artery occluding plus bilateral common carotid arteries occluding group. In the global brain ischemic insult group, rats were further divided into 24 h, 48 h, and 72 h interval subgroups according to the interval between the occlusion of the vertebral arteries and bilateral common carotid arteries. The responses including enlarging of pupils and the light reflex during the brain ischemia were observed. The duration of right reflex disappearing, the general state, and the delayed neuronal death (DND) of pyramidal neurons in the CA1 hippocampus of the rats after the brain ischemia were also observed. RESULTS: Among the global brain ischemic insult group, both the responses and DND were more severe in 72 h interval subgroup than those in 24 h and 48 h interval subgroups. There was no significant difference between 24 h and 48 h interval subgroups. When the bilateral common carotid arteries were occluded under the condition of occlusion of unilateral vertebral artery, severe DND was observed in the CA1 hippocampus ipsilateral to the occluding vertebral artery, but no significant DND was observed in the contralateral CA1 hippocampus. CONCLUSION: The results suggested that the prior occlusion of the bilateral vertebral arteries during producing Pulsinelli 4-vessel occlusion global cerebral ischemic model might be a cerebral ischemic preconditioning that could protect to some extent pyramidal neurons of the hippocampus against severe ischemic insult induced by occlusion of bilateral common carotid arteries within 48 h. Moreover, There is ipsilateral predominance of blood perfusion from one side of vertebral artery to the brainstem and hippocampus, although there was Willis artery circle in rats.