Pentoxifylline Alleviates Early Brain Injury in a Rat Model of Subarachnoid Hemorrhage

Study on the Difference of Protective Efficacy and Mechanism of Radix Aconiti Coreani and Rhizoma Typhonii in Gerbils with Ischemic Stroke

Ischemic stroke is a common type of stroke, but effective treatment methods are still imperfect and new effective therapies need to be explored. Radix Aconiti Coreani and Rhizoma Typhonii used as Baifuzi in the treatment of stroke or symptoms associated with stroke have been recorded in ancient Chinese books and are widely used. Modern pharmacological studies have demonstrated that both of them have antioxidant and anti-inflammatory effects. The purpose of this study is to investigate whether Radix Aconiti Coreani and Rhizoma Typhonii have therapeutical effects on gerbils with ischemic stroke, to investigate their potential mechanisms of action, and to provide a reference for rational clinical application by comparing the differences between them. In this manuscript, the right unilateral ligation of the carotid artery of gerbils was used to cause an ischemic stroke model. The neurological deficits of gerbils in each group were scored by Longa scale. The area of cerebral infarction was detected by 2,3,5-tribenzotetrazolchloride staining. The levels of inflammatory factors, oxidative stress indexes, and vascular endothelial function indexes in brain homogenate and serum were determined by ELISA. The expression levels of P-Akt PI3K, HO-1, and KEAP1 proteins in brain tissue were determined by Western blot. Immunofluorescence staining was used to observe the recovery of neuronal cells in the hippocampal CA1 region of the gerbil brain tissue and the expression of proteins related to PI3K/Akt and KEAP1/Nrf2 signaling pathways in neuronal cells in the hippocampal CA1 region. It was found that Radix Aconiti Coreani and Rhizoma Typhonii could improve neurological deficits and reduce cerebral infarction rate in gerbils. The results showed that Radix Aconiti Coreani and Rhizoma Typhonii could significantly decrease the expression of inflammatory factors, increase the expression of antioxidative stress indexes and vascular endothelial function factors, activate the PI3K/Akt, KEAP1/Nrf2 signaling pathway, reduce the inflammatory response, inhibit the oxidative stress, enhance the vascular endothelial cell function, and thus protect against ischemic brain injury. From the experimental results, both Radix Aconiti Coreani and Rhizoma Typhonii had neuroprotective effects on ischemic brain injury. Compared with Rhizoma Typhonii, the effects of Radix Aconiti Coreani on anti-inflammatory and antioxidative stress were more significant, while Rhizoma Typhonii had showed more significant effects in promoting angiogenesis after ischemic stroke by increasing the level of NO.

The role of the astrocyte in subarachnoid hemorrhage and its therapeutic implications

Subarachnoid hemorrhage (SAH) is an important public health concern with high morbidity and mortality worldwide. SAH induces cell death, blood−brain barrier (BBB) damage, brain edema and oxidative stress. As the most abundant cell type in the central nervous system, astrocytes play an essential role in brain damage and recovery following SAH. This review describes astrocyte activation and polarization after SAH. Astrocytes mediate BBB disruption, glymphatic–lymphatic system dysfunction, oxidative stress, and cell death after SAH. Furthermore, astrocytes engage in abundant crosstalk with other brain cells, such as endothelial cells, neurons, pericytes, microglia and monocytes, after SAH. In addition, astrocytes also exert protective functions in SAH. Finally, we summarize evidence regarding therapeutic approaches aimed at modulating astrocyte function following SAH, which could provide some new leads for future translational therapy to alleviate damage after SAH.

The blood-brain barrier and the neurovascular unit in subarachnoid hemorrhage: molecular events and potential treatments

The response of the blood-brain barrier (BBB) following a stroke, including subarachnoid hemorrhage (SAH), has been studied extensively. The main components of this reaction are endothelial cells, pericytes, and astrocytes that affect microglia, neurons, and vascular smooth muscle cells. SAH induces alterations in individual BBB cells, leading to brain homeostasis disruption. Recent experiments have uncovered many pathophysiological cascades affecting the BBB following SAH. Targeting some of these pathways is important for restoring brain function following SAH. BBB injury occurs immediately after SAH and has long-lasting consequences, but most changes in the pathophysiological cascades occur in the first few days following SAH. These changes determine the development of early brain injury as well as delayed cerebral ischemia. SAH-induced neuroprotection also plays an important role and weakens the negative impact of SAH. Supporting some of these beneficial cascades while attenuating the major pathophysiological pathways might be decisive in inhibiting the negative impact of bleeding in the subarachnoid space. In this review, we attempt a comprehensive overview of the current knowledge on the molecular and cellular changes in the BBB following SAH and their possible modulation by various drugs and substances.

Simultaneous treatment with pentoxifylline does not adversely affect the neurotrophic effects of brain-derived neurotrophic factor on spiral ganglion neurons

The hemorheologic drug pentoxifylline is applied for the treatment of sudden sensorineural hearing loss and tinnitus to improve cochlear microcirculation. Recent studies also suggest protective and trophic effects on neuronal cells. Because the preservation of sensorineural structures of the inner ear is fundamental for normal hearing and hearing restoration with auditory prostheses, pentoxifylline and neurotrophic factors such as brain-derived neurotrophic factor (BDNF) are promising candidates to treat degenerative disorders of the inner ear. We used an in-vitro model to determine the neurotrophic effects of these factors on spiral ganglion cells from postnatal rats. Pentoxifylline, alone and in combination with BDNF, was added at various concentrations to the cultured cells. Cells were immunolabeled and analyzed to determine neuronal survival, neurite length, neuronal branching and morphology. Pentoxifylline did not significantly increase or decrease neuronal survival, neurite length and neuronal branching compared to control cultures. Analysis of cellular morphology showed that diverse neuronal subtypes developed in the presence of pentoxifylline. Our data revealed that pentoxifylline did not interfere with the robust neurotrophic effects of BDNF on spiral ganglion neurons when cultured cells were treated with pentoxifylline and BDNF simultaneously. The results of our study do not suggest major neurotrophic effects of pentoxifylline on cultured spiral ganglion neurons. Because pentoxifylline has no detrimental effects on spiral ganglion neurons and does not reduce the effects of BDNF, both agents could be combined to treat diseases of the inner ear provided that future in vivo experiments and clinical studies support these findings.

The effect of pentoxifylline on cerebral vasospasm following experimental subarachnoid hemorrhage

OBJECTS

Cerebral vasospasm is an important event that occurs following subarachnoid hemorage which has significant mortality and morbidity. The goal in this study was to investigate the effect of pentoxifylline on vasospasm in an experimental subarachnoid hemorrhage model.

METHODS

In this study, 20 male New Zeland White rabbits weighing 3000-3500 g were assigned randomly to four groups. Animals in group 1 served as controls. Animals in group two received only intravenous pentoxifylline injection 3 times in 12 h intervals. In group 3, SAH was induced and no injection was given. Animals in group 4 received intravenous pentoxifylline (6 mg/kg) injections 3 times at 12^th, 24^th and 36^th hours after subarachnoid hemorrhage induction. All animals were sacrificed and basilar arteries were removed at 48th hour. Basilar artery vessel diameters, wall thicknesses and luminal section areas were measured with Spot for Windows version 4.1. Statistical analysis was performed using ANOVA and Kruskall-Wallis tests.

RESULTS

Mean basilar artery luminal section areas and luminal diameters in group 4 were significantly higher compared to group 3 (p < 0.05). Basilar artery wall thicknesses and were found to be higher in group 3 than in other groups and this was also statistically significant (p < 0.05).

CONCLUSION

Our study demonstrated that intravenous administration of pentoxifylline significantly decreases vasospasm after subarachnoid hemorrhage.

Expression of caspase-3, Bax and Bcl-2 in hippocampus of rats with diabetes and subarachnoid hemorrhage

The expression of caspase-3, Bax and Bcl-2 in hippocampus of rats with diabetes and subarachnoid hemorrhage (SAH) were investigated. Diabetes mellitus model was established by intraperitoneal injection of STZ. On the basis of diabetes mellitus model, SAH animal model was established by injecting fresh autologous femoral artery blood into cerebellomedullary cisten. Rats were divided into blank control group, diabetes control group and diabetes + SAH group. TUNEL method was used to detect cell apoptosis of hippocampus. Expression levels of caspase-3, Bax and Bcl-2 were detected by real-time quantitative reverse transcription PCR and western blot analysis at mRNA and protein levels, respectively. Apoptotic cells were not detected in blank control group and diabetes group, and number of apoptotic cells was the highest in the diabetic SAH group. Expression levels of caspase-3, Bax and Bcl-2 mRNA and protein were significantly higher in diabetes + SAH group than in blank control group and diabetes group. In conclusion, Hippocampal neuron apoptosis was induced by diabetes + SAH and expression levels of caspase-3, Bax and Bcl-2 were also increased. Our study provided experimental basis for further studies of the relationship between SAH and cell apoptosis.