Effect of l -Dopa in acute temozolomide-induced cognitive impairment in male mice: a possible antineuroinflammatory role.

Temozolomide is used commonly in the treatment of some types of cancers, but it may also result in cognitive impairments such as memory deficits. l -Dopa, a well known medicine for the central nervous system, has been shown to have positive effects on some cognitive disorders. Here we sought to investigate the effect of l -Dopa on temozolomide-induced cognitive impairments. BALB/c mice were subjected to 3-days temozolomide and 6-days concomitant l -Dopa/benserazide administration in six groups (control, l -Dopa 25 mg/kg, l -Dopa 75 mg/kg, temozolomide, temozolomide +  l -Dopa 25 mg/kg, and temozolomide +  l -Dopa 75 mg/kg). Open field test, object location recognition, novel object recognition test, and shuttle-box test were carried out to determine the locomotor, anxiety-like behavior, and memory function of subjects. TNF-α and brain-derived neurotrophic factor (BDNF) gene expression in the hippocampus was measured by real-time PCR. Mice treated with temozolomide showed recognition memory impairment, along with hippocampal TNF-α and BDNF mRNA expression level raise, and detection of histological insults in hematoxylin and eosin hippocampal slides. Mice that received temozolomide +  l -Dopa showed normal behavioral function and lower TNF-α and BDNF hippocampal mRNA expression levels, and histologically normal hippocampal CA1 region in comparison with mice in the temozolomide group. Our results provide evidence that l -Dopa prevents temozolomide-induced recognition memory deficit in mice at the acute phase probably via l -Dopa antineuroinflammatory effects.

Effects of genistein on cognitive dysfunction and hippocampal synaptic plasticity impairment in an ovariectomized rat kainic acid model of seizure.

The major objective of this study was to investigate the probable effects of genistein (one of the most important soy phytoestrogens-SPEs) on seizure-induced cognitive dysfunction, hippocampal early long-term potentiation (E-LTP) impairment and morphological damage to CA1 neurons in ovariectomized (OVX) rats. Three weeks after ovariectomy, cannulae were implanted over the left lateral ventricle. After a 7-day recovery period, animals were injected by genistein (0.5 or 5mg/kg) or vehicle during four consecutive days, each 24h. One h after the last treatment, kainic acid (KA) or vehicle was perfused into the left lateral ventricle to induce generalized tonic-clonic seizures. Finally, 7 days later, spatial learning and memory of animals were examined using the Morris water maze (MWM) task, hippocampal E-LTP was assessed using in-vivo field potential recordings and the morphology of hippocampal CA1 area was examined using Fluoro-Jade C staining. KA-induced generalized seizures resulted in spatial learning and memory impairment, E-LTP deficit and CA1 cell injury. Seizure-induced abnormalities improved partially only by the lower dose of genistein (0.5mg/kg). However, genistein at the higher dose (5mg/kg) did not have any beneficial effects. Also, genistein did not affect seizure activity. It is concluded that genistein may have partially preventive effects against seizure-induced cognitive impairment in OVX rats. Also, it seems that such effects of genistein are correlated with its beneficial effects on hippocampal synaptic plasticity and morphology.

Coadministration of the Human Umbilical Cord Matrix-Derived Mesenchymal Cells and Aspirin Alters Postischemic Brain Injury in Rats.

BACKGROUND: Ischemic stroke is an acute brain insult that induces dramatic changes in the neurons. Treatment of brain stroke is one of the main therapeutic targets of neuroprotective therapies. The aim of this study was to evaluate the protective potential of implanted human umbilical cord mesenchymal stem (hUCMs) cells with/without aspirin (ASA) against focal cerebral ischemia. METHODS: We assessed the migration and distribution of PKH26-labeled cells after transplantation. After day 10 of transient occlusion, we evaluated the effect of ASA and hUCMs on the recovery of learning and memory in rats by Morris water maze. Afterward, animals were sacrificed, and the infarct area in the brain was evaluated using 2, 3, 5-triphenyltetrazolium chloride staining and also by hematoxylin and eosin. RESULTS: The recovery of learning and memory in ischemic animals that received ASA and hUCM cells improved significantly compared with the untreated ischemic animals. Coadministration of ASA and hUCM cells did not improve the outcome at a comparable rate with ASA and hUCM cells alone. PKH26-labeled cells were detectable in the ischemic area of the brain tissue sections. 2,3,5-Triphenyltetrazolium chloride staining and histologic examinations showed that treatment with ASA and hUCM cells could significantly alter the ischemic area. CONCLUSIONS: The results of the present study suggest that ASA and hUCM cells can withstand degenerative changes induced by artificial stroke in the rat. Also the learning and memory disturbance in the ASA and cell-treated animals is less pronounced than ischemic animals. Coadministration of ASA and hUCM cells did not raise the outcome higher than administration of ASA and hUCM cells alone.

Exercise improves learning and memory impairments in sleep deprived female rats.

Inadequate sleep is a common problem in modern societies. It has been previously shown that female rats are more vulnerable to the deleterious effects of sleep deprivation on cognitive functions. Physical exercise has been suggested to attenuate the cognitive impairments induced by sleep deprivation in male rats. The objective of the current study was to investigate the effects of physical exercise on cognitive functions of female rats following paradoxical sleep deprivation. Intact and ovariectomized (OVX) female Wistar rats were used in the present study. The exercise protocol was 4 weeks of treadmill running. The multiple platform method was applied for the induction of 72h paradoxical sleep deprivation and the cognitive function was evaluated using Morris water maze (MWM). Plasma corticosterone level was evaluated in separate groups of study. ANOVA and repeated measures were used to analyze the data and P<0.05 was considered statistically significant. Throughout the investigation, significant learning impairment was observed in sleep-deprived OVX rats compared to the intact and the other OVX groups. Short term memory impairment was observed in both sleep-deprived OVX and intact groups. Physical exercise alleviated the PSD-induced learning and memory impairments in both intact and OVX groups. Corticosterone levels were not statistically significant among the different groups. The results of our study confirmed the negative effects of PSD on cognitive functions in female rats and regular physical exercise seems to protect rats from these effects. Further studies are suggested to be carried out in order to evaluate the possible underlying mechanisms, and also to evaluate the possible interactions between sex hormones and PSD-induced cognitive impairments.

Maternal feeding with walnuts (Juglans regia) improves learning and memory in their adult pups.

OBJECTIVE: Walnut (Juglans Regia) is a domestic fruit of Iran. Walnut kernel (WK) has many beneficial constituents such as unsaturated fatty acids, antioxidants, and vitamin E. Scientific studies have shown that fatty acids and vitamin E can modulate learning and memory processes. The aim of the present work was to study effects of walnut consumption by mothers during pregnancy and lactation on learning and memory in adult rat offsprings. MATERIALS AND METHODS: The animals were divided into three groups: control (fed with ordinary food, 20 g daily), gestation (fed with WK, 6% of food intake during pregnancy), and gestation and lactation (fed with WK, 6% of food intake during gestation and lactation). Morris water maze test was performed for their adult offsprings. RESULTS: The results showed that there was a significant difference in learning and memory of rat offsprings between experimental and control groups. CONCLUSION: These data may indicate that feeding mothers with WK results in improvement in learning and memory of their offsprings.

Walnut consumption protects rats against cisplatin-induced neurotoxicity.

Walnut is extensively used in traditional medicine for treatment of various ailments. It is described as an anticancer, anti-inflammatory, blood purifier and antioxidant agent. In this study, we investigated whether or not Walnut could protect neurons against cisplatin-induced neurotoxicity in rats. Dietary walnut (6%) was assessed for its neuroprotective effects through the alteration in performance of hippocampus- and cerebellum-related behaviors following chronic cisplatin treatment (5 mg/kg/week for 5 consecutive weeks) in male rats. We also evaluated the effect of cisplatin and walnut administration on nociception. We showed that exposure of adolescent rats to cisplatin resulted in significant decrease in explorative behaviors and memory retention. Walnut consumption improved memory and motor abilities in cisplatin treated rats, while walnut alone did not show any significant changes in these abilities compared to saline. Cisplatin increased latency of response to nociception, and walnut reversed this effect of cisplatin. We conclude that walnuts in the diet following anticancer drugs such as cisplatin might have a protective effect against cisplatin-induced disruptions in motor and cognitive function. However, further studies are needed to elucidate the exact mechanisms of this protective effect of walnut and to explore underlying mechanisms.

Olive (Olea europaea L.) leaf extract elicits antinociceptive activity, potentiates morphine analgesia and suppresses morphine hyperalgesia in rats.

AIM OF THE STUDY: Olive (Olea europaea) leaves are used as anti-rheumatic, anti-inflammatory, antinociceptive, antipyretic, vasodilatory, hypotensive, antidiuretic and hypoglycemic agents in traditional medicine. Recently, it has been shown that olive leaf extract (OLE) has calcium channel blocker property; however, its influences on nociceptive threshold and morphine effects have not yet been clarified. MATERIALS AND METHODS: All experiments were carried out on male Wistar rats. The tail-flick, hot-plate and formalin tests were used to assess the effect of OLE on nociceptive threshold. To determine the effect of OLE on analgesic and hyperalgesic effects of morphine, OLE (6, 12 and 25 mg/kg i.p.) that had no significant nociceptive effect, was injected concomitant with morphine (5 mg/kg and 1 µg/kg i.p., respectively). The tail-flick test was used to assess the effect of OLE on anti- and pro-nociceptive effects of morphine. RESULTS: The data showed that OLE (50-200 mg/kg i.p.) could produce dose-dependent analgesic effect on tail-flick and hot-plate tests. Administration of 200 mg/kg OLE (i.p.) caused significant decrease in pain responses in the first and the second phases of formalin test. In addition, OLE could potentiate the antinociceptive effect of 5 mg/kg morphine and block low-dose morphine-induced hyperalgesia. CONCLUSION: Our results indicate that olive leaf extract has analgesic property in several models of pain and useful influence on morphine analgesia in rats. Therefore, it can be used for the treatment and/or management of painful conditions.