Evaluation of betulinic acid effects on pain, memory, anxiety, catalepsy, and oxidative stress in animal model of Parkinson's disease.

Parkinson's disease (PD) is known for motor impairments. Betulinic acid (BA) is a natural compound with antioxidant activity. The present study addresses the question of whether BA affects motor and non-motor dysfunctions and molecular changes in the rat model of PD. The right medial forebrain bundle was lesioned by injection of 6-hydroxydopamine in Male Wistar rats (10-12 weeks old, 270-320 g). Animals were divided into Sham, PD, 3 treated groups with BA (0.5, 5, and 10 mg/kg, IP), and a positive control group received L-dopa (20 mg/kg, P.O) for 7 days. rigidity, anxiety, analgesia, and memory were assessed by bar test, open-field, elevated plus-maze (EPM), tail-flick, and shuttle box. Additionally, the malondialdehyde (MDA), Superoxide dismutase (SOD), glutathione peroxidase (GPx) activity, Brain-derived neurotrophic factor (BDNF) and Interleukin 10 (IL10) levels in the whole brain were measured. BA significantly reversed the 6-hydroxydopamine-induced motor and memory complication in the bar test and shuttle box. It modified anxiety-like behavior neither in open-field nor in EPM. It only decreased the time spent in open arms. Moreover, no significant changes were found in the tail-flick between treatment and sham groups. On the other hand, the level of MDA & IL10 were decreased, while the activity of GPx levels of SOD & BDNF in the rats' brains was increased. Our results showed that BA as a free radical scavenger can account for a possible promise as a good therapeutic agent for motor and non-motor complications in PD however further studies may be needed.

Lovastatin attenuates glyoxal-induced toxicity on rat liver mitochondria.

Alpha-dicarbonyls such as glyoxal (GO) trigger mitochondrial dysfunction resulting in the development of different diabetic complications. The present study investigated the effects of lovastatin against GO-induced toxicity on rat liver mitochondria. The rat liver mitochondria (0.5 mg protein/mL) were treated with various concentrations of lovastatin (1, 5, 10 µM) at 37°C for 30 min and then exposed to GO (3 mM) at 37°C for 30 min. Oxidative stress markers including MDA, reactive oxygen species (ROS), glutathione (GSH) and protein carbonylation (PC) level were measured. Mitochondrial complex II activity and mitochondrial membrane potential (MMP) were assessed for evaluating mitochondrial function. Glyoxal significantly increased the level of ROS, PC and MDA. This effect was associated with the reduction of MMP, complex II activity and GSH content. Pre-treatment with lovastatin potentially reversed GO-induced mitochondrial toxicity. These results suggest that lovastatin have a protective effect against GO-induced toxicity in isolated rat liver mitochondria.

GALLIC ACID IMPROVES OXIDATIVE STRESS AND INFLAMMATION THROUGH REGULATING MICRORNAS EXPRESSIONS IN THE BLOOD OF DIABETIC RATS.

CONTEXT: Endothelial dysfunction and diabetic cardiomyopathy are critical complications of diabetes. Gallic acid (GA) plays a significant role in cardiovascular disorders resulted from diabetes. In addition, increased plasma miR-24, miR-126 associated with endothelial dysfunction. AIM: The current study was designed to assess the effects of GA on plasma miR-24, miR-126 levels in the diabetic rats. ANIMALS AND METHODS: Adult male Sprague-Dawley rats were divided into three groups (n=8): control (C), diabetic (D) and diabetic group treated with GA (D+G, 25 mg/kg, by gavage) for eight weeks. The blood glucose level, body weight, lipid profile, blood pressure, plasma miR-24 and miR-126 levels, antioxidant and inflammatory biomarkers were measured. RESULTS: The plasma levels of miR-24, miR-126, body weight, high-density lipoprotein cholesterol (HDL-c), total anti-oxidant capacity (TAC) and the systolic blood pressure significantly reduced and blood glucose, total cholesterol (TC), triglycerides (TG), very low-density lipoprotein cholesterol (VLDL-c), malondialdehyde (MDA), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and low-density lipoprotein cholesterol (LDL-c) significantly elevated among the diabetic rats compared with the control group. However, GA restored body weight, blood pressure, TC, TG, VLDL-c, TNF-α, miR-126, blood glucose, HDL-c, MDA, TAC, miR-24 and IL-6 among the GA treated rats compared with the diabetic group. CONCLUSION: GA improves inflammation, oxidative stress and hypotension result from diabetes. These protective effects are probably mediated via increasing plasma miR-24 and miR-126 levels.

Delayed gastric emptying in diabetic rats caused by decreased expression of cystathionine gamma lyase and H2 S synthesis: in vitro and in vivo studies.

BACKGROUND: This study aimed to evaluate the role of H2 S on gastric emptying rate (GER) and also to determine the effect of gastric distention on mRNA and protein expression of cystathionine ß-lyase (CBS) and cystathionine γ-synthase (CSE) in diabetic-gastroparetic and normal rats. METHODS: Adult normal rats intraperitoneally received either propargylglycine (PAG), L-cysteine or NaHS 30 min prior to GER marker (acetaminophen) to investigate H2 S involvement in GER and the same protocols were performed in diabetes-induced gastroparesis rats. The role of calcitonin gene related peptide (CGRP) neurons in the prokinetic effect of endogenous H2 S on GER was determined. The level of CBS and CSE expressions in response to gastric distention were also determined. The effect of H2 S on frequency and tension of spontaneous contractions of gastric smooth muscle strips was investigated. KEY RESULTS: Our results showed that: (i) H2 S and L-cysteine increased GER in gastroparetic and normal rats. (ii) The increased levels of CSE expression in response to gastric distention in diabetic rats were lower than in normal rats. (iii) PAG inhibited the excitatory effect of capsaicin on GER and on tension of spontaneous contractions of strips. (iv) Hydrogen sulphide increased the frequency and tension of spontaneous contractions of gastric strip muscles in normal and diabetic rats. CONCLUSIONS & INFERENCES: The results showed that delayed GER in diabetic rats can be due to down-regulation of H2 S biosynthesis enzyme, CSE and suggested that a potential prokinetic role for H2 S to treat the delayed gastric emptying in diabetic patients.

Effect of beta carotene on lipid peroxidation and antioxidant status following renal ischemia/reperfusion injury in rat.

BACKGROUND: The production of free radicals and reactive oxygen species are important factors contributing to ischemia/reperfusion injury. Thus scavenging of the excess free radicals can be an important therapeutic approach. Beta carotene, a carotenoid pigment has a potent antioxidant property. The present study examined the effect of beta carotene administration on the level of renal content of antioxidants and lipid peroxidation following ischemia/reperfusion injury in the rat kidney. METHODS: Male adult Wistar rats (250-300 g) were exposed to 45 min of renal ischemia followed by 4 h of reperfusion. Beta carotene (10, 30 and 100 mg kg(-1)) or vehicle was administered for 5 days prior to ischemia. Renal content of antioxidants and the level of lipid peroxidation were measured after the reperfusion period. RESULTS: Our results showed that ischemia/reperfusion injury increased lipid peroxidation (p < 0.001) and decreased antioxidant (p < 0.001) in renal tissue. Pre-administration of beta carotene could attenuate these alterations (p < 0.05-p < 0.001), although not at all doses. Since beta carotene administration improved renal lipid peroxidation and antioxidants, it seems that beta carotene protects renal tissue against ischemia/reperfusion-induced oxidative damage.

Forced exercise improves passive avoidance memory in morphine-exposed rats.

The aim of this study was to investigate the effect of short-term forced exercise protocol on passive avoidance retention in morphine-exposed rats. Effects of morphine on acquisition and retrieval of retention have been proven in the avoidance paradigms. Twenty four male Wistar rats weighing 250-300 g were used in this study. Animals were randomly divided into four groups including: (1) non-morphine-exposed without exercise (nA.nE) (2) non-morphine-exposed with exercise (nA.E) (3) morphine-exposed without exercise (A.nE) and (4) morphine-exposed with exercise (A.E). Rats ran as forced exercise on the motorized treadmill 1 h daily for ten days. Morphine-exposed animals received intraperitoneal morphine during first 5 days of the exercise period and their dependence to morphine was confirmed by naloxane admistration (10 mg kg(-1), i.p.) and withdrawal test. After 10 days of forced exercise, step down latency was tested and Inflexion Ratio (IR) was evaluated in each rat. Baseline step down latencies before any morphine exposing or exercise have shown no significant alteration in all groups. Inflexion Ratio (IR) ofnA.E group has increased significantly (p<0.001) at 1, 3, 7 and 14 days after receiving shock (learning) compared to nA.nE and A.E groups. Our data showed that short-term forced exercise on treadmill improved retention in both morphine-exposed and non morphine-exposed rats at least up to 7 days and more than 14 days, respectively. Alteration in retention between exercised groups may attribute the release of adrenal stress hormones such as epinephrine and corticosterone because of the emotional arousal.

Protective effect of beta carotene pretreatment on renal ischemia/reperfusion injury in rat.

Renal ischemia/reperfusion injury is a major cause of acute renal failure. The production of free radicals and reactive oxygen species are important factors contributing to ischemia/reperfusion injury. Thus, scavenging of the excess free radicals can be an important therapeutic approach. The present study examined the protective effect of beta carotene against renal ischemia/reperfusion injury in rat. Male adult Wistar rats (250-300 g) were exposed to 45 min of renal ischemia followed by 4 h of reperfusion. Beta carotene (10, 30 and 100 mg kg(-1)) or vehicle was administered for 5 days prior to ischemia. Renal function was assessed by plasma and urinary analysis. Present results showed that ischemia/reperfusion injury increased (p < 0.05-p < 0.001) serum urea and creatinine levels, as well as urinary excretion of protein and calcium and fractional excretion of sodium, while decreased glomerular filtration rate and potassium excretion. However, alterations in these biochemical indices due to ischemia/reperfusion injury were attenuated by beta carotene pretreatment (p < 0.05-p < 0.001), although not by all doses. Since, beta carotene administration improved renal function, it seems that beta carotene protects renal tissue against ischemia/reperfusion-induced oxidative damage.

The effect of peripheral administration of growth hormone on AD-like cognitive deficiency in NBM-lesioned rats.

This study aimed to evaluate the peripheral administration of growth hormone (GH) on AD-like cognitive deficiency in NBM-lesioned rats induced by ibotenic acid (5 microg/microl, in each side). Forty-eight male Wistar rats (20-24 months old; weighing 330+/-30 g) randomly divided into six groups (n=8). The groups include control group, which were intact rats; n-L+GH group: non-lesioned rats with GH treatment (1mg/kg, 9.00 am, for 10 consecutive days); n-L+Veh group: non-lesioned rats with vehicle treatment; L group: NBM-lesioned rats; L+GH group: NBM-lesioned rats with GH treatment and L+Veh group: NBM-lesioned rats with same volume of vehicle treatment. Peripheral administration of GH in control had no effect on learning and memory, while in L+GH group produced a significant enhancement in spatial learning and memory comparing to L and L+Veh groups. The percent of time spent in goal quarter during probe trial has decreased significantly in L and L+Veh groups compared to n-L groups. While it has increased significantly in L+GH group compared to L and L+Veh groups. No significant difference in percent of time spent was seen between the control and n-L groups. The GH has known as a mediate that effect through IGF-1. As the IGF-1 itself is earlier shown to improve cognitive function it is likely that the observed effect of GH is mediated through release of IGF-1 from peripheral tissue into the circulation for further transport across the BBB. This mechanism may result in the improvement of learning and memory in rats with NBM lesion.

Preventive effects of soy meal (+/- isoflavone) on spatial cognitive deficiency and body weight in an ovariectomized animal model of Parkinson's disease.

The aim of the present study was to investigate the preventive effect of 4 weeks soy meal (+/- isoflavone) on post-menopausal cognitive deficiency and body weight alteration in ovariectomized (OVX)-6-hydroxy dopamine (6-OHDA)-induced animal model of Parkinson's Disease (PD) which mimics status in menopause women. Female Wistar rats (250-300 g, 5-6 months old) were divided into 2 main groups. (1) Control; (2) OVX; included 5 subgroups that were pre-treated with 10 or 20 g soy with isoflavone in 30 g daily diet (10 and 20 groups, respectively), 10 or 20 g soy without isoflavone in 30 g daily diet (-10 and -20 groups, respectively) and 0 g soy (sham treated group) during 4 weeks after OVX. To induce animal model ofPD in main second group (OVX rats) the substantia nigra pars compacta (SNpc) was lesioned by 6-hydroxydopamine (6-OHDA) (8 microg kg(-1) 4 microL(-1) normal saline contains 0.1% ascorbate). All animals were trained in Morris water maze for evaluating the spatial learning and memory. The results indicated that pre-treatment of Parkinsonian rats with different doses of dietary soy meal (+/- isoflavone) improved the spatial learning and memory and prevents increasing the body weight after menopause significantly. Our data show that, long-duration dietary soy meal may have the potential neuroprotective effect against post-menopausal cognitive deficiency induced by degeneration of nigrostriatal dopaminergic system and constant body weight during post-menopausal life cycle.

Postmenopausal effects of intrastriatal estrogen on catalepsy and pallidal electroencephalogram in an animal model of Parkinson's disease.

The main objective was to test the preventive and treatment effects of central injection of estrogen (ES) on muscular rigidity and pallidal EEG in menopausal rats' model of Parkinson's disease (PD). We hypothesized that intrastriatal pretreatment and post-lesion treatment by estrogen improve the pallidal local EEG and muscular stiffness in animal model of menopause with PD. Forty-eight female Wistar rats (300-350 g) were ovariectomized (OVX) and divided into two main groups: Non-pretreated subgroups; sham (S), lesioned (L), post-lesion treated (LT) and pretreated subgroups; pretreated (Pt), pretreated and then lesioned (PtL), pretreated and post-lesion treated (PtLT). Pallidal local EEG was recorded by a bipolar recording electrode and muscle stiffness was scored by Dekundy's test in freely moving rats. Muscle stiffness and pallidal local EEG were indicated as main outcome measures. In pretreated group the local pallidal EEG was decreased in sham-operated rats compared with non-pretreated group (P<0.01), and SNc lesioning decreased EEG in the non-pretreated (P<0.01), while it increased the EEG in the pretreated group (P<0.01). In both groups administration of ES restore the EEG to the respective sham-operated group (P<0.01). Regarding muscle stiffness, it increased after SNc lesioning in both pretreated and non-pretreated groups and ES administration decreased the rigidity significantly (P<0.05, P<0.001 respectively). However, the lesion-induced rigidity in pretreated groups was significantly less than non-pretreated groups (P<0.05). Because of its modulatory effect estrogen may protect dopaminergic neurons from injury and may interfere with the uptake of 6-hydroxydopamine (6-OHDA) into the nigral dopaminergic neurons or alter dopamine release and uptake in remaining neurons.

Decreased response of rat knee joint blood vessels to phenylephrine in chronic inflammation: involvement of nitric oxide.

The effect of chronic inflammation induced by Freund's Complete Adjuvant (FCA) on rat articular blood vessels and knee joint diameter was investigated. Blood flow changes in response to phenylephrine (an 1-adrenoceptor agonist) in FCA-treated and contralateral knee joints were studied over a 40 day period, using the laser Doppler flowmetery (LDF) technique. Unilateral injection of FCA (0.2 ml) increased the injected knee diameter on all days examined post-injection (P < 0.001) and its maximum increase (53 +/- 2 %) was reached on day 3. After this, the diameter decreased gradually but did not return to its initial value. In control animals, topical application of 10-13-10- 7 mol phenylephrine onto the exposed joint capsule decreased blood flow dose dependently (11. 1 +/- 4.4 to 58.2 +/- 4.5 %, respectively, P < 0.001). Unilateral injection with FCA attenuated the phenylephrine response in both ipsilateral and contralateral knees compared with the response of control animals (5.2 +/- 1.6 to 48.3 +/- 6.1 % and 1.9 +/- 2.2 to 45. 3 +/- 5.6 %, respectively, P < 0.05). The reduction persisted for 3 weeks after FCA injection (ipsilateral for 21 days; contralateral for 30 days, P < 0.001). Subsequently the response returned towards normal. To avoid the influence of 2-adrenoceptors, yohimbine (an 2-adrenoceptor antagonist) was injected (0.5 mg kg-1, I.P.) 30 min before phenylephrine application. Yohimbine blocked the vasoconstrictor effect of 10-10-10-7 mol clonidine (an 2-adrenoceptor agonist, topical application) by 44-67.7 % inhibition, respectively (P < 0.001). Prazosin (an 1-adrenoceptor antagonist, 0.1 mg kg-1, I.P.) blocked the vasoconstrictor effect of phenylephrine (10-10-10-7 mol, topical application) effectively (42 to 69.8 % inhibition, respectively, P < 0.001). To assess the role of nitric oxide (NO) on the observed responses, N G-nitro-L-arginine methyl ester (L-NAME, NO synthase inhibitor) was applied topically (0.2 micromol) 5 min before phenylephrine application. L-NAME application at 7 and 14 days after FCA injection potentiated the vasoconstrictor response in the FCA-treated knee (P < 0.001) but had no significant effect on the contralateral knee. Blood pressure monitoring during phenylephrine, clonidine and L-NAME administration indicated that topical application of the drugs had no significant effect on the systemic blood pressure. These findings indicate that the vasoconstrictor response to phenylephrine was decreased in chronic inflammation and increased NO production could be involved.

Bombesin-induced anorexia requires central bombesin receptor activation: independence from interaction with central catecholaminergic systems.

Intraperitoneal (IP) administration of bombesin (BBS; 2.5-20 micrograms/kg) induced a dose-dependent inhibition of food intake. The effect was decreased by intraventricular (ICV) administration of bombesin receptor antagonist [Leu14-psi (CH2NH)-Leu13] (3 micrograms/rat) but not by the D1 antagonist SCH 23390, the D2 antagonists sulpiride and pimozide, the dopamine antagonist cis-flupentixol, adrenoceptor blockers phenoxybenzamine or propranolol and serotonergic antagonist methergoline. It is concluded that BBS-induced suppression of feeding may be mediated through central BBS receptors, and is independent of interaction with brain catecholaminergic system.