Caloric and time restriction diets improve acute kidney injury in experimental menopausal rats: role of silent information regulator 2 homolog 1 and transforming growth factor beta 1.

BACKGROUND: Estrogen has a protective impact on acute kidney injury (AKI); moreover, reducing the daily intake of calories impedes developing diseases. The present study aimed to determine the effects of calorie restriction (CR) and time restriction (TR) diets on the expression of silent information regulator 2 homolog 1 (SIRT1), transforming growth factor beta 1 (TGF-ß1), and other indicators in the presence and absence of ovaries in AKI female rats. METHODS: The female rats were divided into two groups, ovariectomized (OVX) and sham, and were placed on CR and TR diets for eight weeks; afterward, AKI was induced by injecting glycerol, and kidney injury indicators and biochemical parameters were measured before and after AKI. RESULTS: After AKI, the levels of urine albumin excretion rate, urea, and creatinine in serum, and TGF-ß1 increased, while creatinine clearance and SIRT1 decreased in kidney tissue. CR improved kidney indicators and caused a reduction in TGF-ß1 and an increase in SIRT1 in ovary-intact rats. Moreover, CR prevented total antioxidant capacity (TAC) decrease and malondialdehyde (MDA) increase resulting from AKI. Before AKI, an increase in body weight, fasting blood sugar (FBS), low-density lipoprotein (LDL), triglyceride (TG), and total cholesterol (TC), and a decrease in high-density lipoprotein (HDL) were observed in OVX rats compared to sham rats, but CR prevented these changes. The effects of TR were similar to those of CR in all indicators except for TGF-ß1, SIRT1, urea, creatinine, and albumin. CONCLUSION: The present study indicated that CR is more effective than TR in preventing AKI, probably by increasing SIRT1 and decreasing TGF-ß1 in ovary-intact animals.

Cardioprotective effects of calorie restriction against inflammation and apoptosis in ovariectomized obese rats: Role of classical estrogen receptors and SIRT1.

AIM: Obesity is a metabolic complication linked with bad eating habits and a sedentary lifestyle, and the heart is one of the target organs damaged by it. Estrogen deficiency during menopause worsens the situation. Calorie restriction (CR) can contribute to reducing cardiovascular disease (CVD) in postmenopausal conditions. Thus, the effects of CR on inflammation and apoptosis in ovariectomized rats' hearts with obesity were studied. METHOD: Female Wistar rats were categorized into Sham and OVX (ovariectomized) groups and received a standard diet (SD) or high-fat diet (60%HFD) or calorie restriction (30% CR) for 16 weeks. The real-time PCR method was used to evaluate the inflammatory markers and estrogen receptors gene expression. Western-blot and ELISA methods were respectively used for the measurement of apoptosis and SIRT1 protein expression. RESULTS: HFD led to the elevation of body weight, IL-6 (interleukin-6) and TNF-α (tumor necrosis factor-α) and reduction of IL-10 (interleukin-10) gene expressions, and also an increment in protein levels of cleaved caspase-3, Bax and Bax/Bcl2 ratio and decrement in Bcl-2 in OVX rats (P < 0.001). Additionally, HFD reduced SIRT1 (sirtuin1) protein levels, ERα (estrogen receptor α), and ERß (estrogen receptor ß) gene expressions (P < 0.001). In contrast, CR declined body weight, IL-6 and TNF-α (P < 0.001), increased IL-10 expressions (P < 0.05), decreased cleaved caspase-3 (P < 0.001), Bax (P < 0.01), and Bax/Bcl2 ratio (P < 0.05), enhanced Bcl-2 (P < 0.001), increased SIRT1 (P < 0.05) and ERα (P < 0.001) and ERß (P < 0.01) expressions. CONCLUSION: CR through the SIRT1 regulation and estrogen receptors attenuate obesity-induced-cardiac inflammation and apoptosis. CR can be a cardioprotective candidate in postmenopausal conditions.

Protective effects of calorie restriction and 17-ß estradiol on cardiac hypertrophy in ovariectomized obese rats.

Obesity and menopause lead to cardiovascular diseases. Calorie restriction (CR) can modulate estrogen deficiency and obesity-related cardiovascular diseases. The protective effects of CR and estradiol on cardiac hypertrophy in ovariectomized obese rats were explored in this study. The adult female Wistar rats were divided into sham and ovariectomized (OVX) groups that received a high-fat diet (60% HFD) or standard diet (SD) or 30% CR for 16 weeks, and then, 1mg/kg E2 (17-ß estradiol) was injected intraperitoneally every 4 days for four weeks in OVX-rats. Hemodynamic parameters were evaluated before and after each diet. Heart tissues were collected for biochemical, histological, and molecular analysis. HFD consumption led to weight gain in sham and OVX rats. In contrast, CR and E2 led to body weight loss in these animals. Also, heart weight (HW), heart weight/body weight (HW/BW) ratio, and left ventricular weight (LVW) were enhanced in OVX rats that received SD and HFD. E2 reduced these indexes in both diet conditions but reduction effects of CR were seen only in HFD groups. HFD and SD feeding increased hemodynamic parameters, ANP (atrial natriuretic peptide) mRNA expression, and TGF-ß1(transforming growth factor-beta 1) protein level in the OVX animals, while CR and E2 reduced these factors. Cardiomyocyte diameter and hydroxyproline content were increased in the OVX-HFD groups. Nevertheless, CR and E2 decreased these indicators. The results showed that CR and E2 treatment reduced obesity-induced-cardiac hypertrophy in ovariectomized groups (20% and 24% respectively). CR appears to have almost as reducing effects as estrogen therapy on cardiac hypertrophy. The findings suggest that CR can be considered a therapeutic candidate for postmenopausal cardiovascular disease.

Beneficial effects of time and energy restriction diets on the development of experimental acute kidney injury in Rat: Bax/Bcl-2 and histopathological evaluation.

People's lifestyles and, especially, their eating habits affect their health and the functioning of the organs in their bodies, including the kidneys. One's diet influences the cells' responses to stressful conditions such as acute kidney injury (AKI). This study aims to determine the preconditioning effects of four different diets: energy restriction (ER) diet, time restriction (TR) eating, intermittent fasting (IF), and high-fat diet (HF) on histopathological indices of the kidney as well as the molecules involved in apoptosis during AKI. Adult male rats underwent ER, TR, IF, and HF diets for eight weeks. Then, AKI was induced, and renal function indices, histopathological indices, and molecules involved in apoptosis were measured. In animals with AKI, urinary albumin excretion, serum urea, creatinine and, Bax/Bcl-2 ratio increased in the kidney, while renal eGFR decreased. ER and TR diets improved renal parameters and prevented an increase in the Bax/Bcl-2 ratio. The IF diet improved renal parameters but had no effect on the Bax/Bcl-2 ratio. On the other hand, the HF diet worsened renal function and increased the Bax/Bcl-2 ratio. Histopathological examination also showed improved kidney conditions in the ER and TR groups and more damage in the HF group. This study demonstrated that ER and TR diets have renoprotective effects on AKI and possibly cause the resistance of kidney cells to damage by reducing the Bax/Bcl-2 ratio and improving apoptotic conditions.

Anti-tumor effects of Thymus Caramanicus Jalas extract in mice through oxidative stress, inflammation and apoptosis.

OBJECTIVE: Breast cancer causes death in women. Thymus Caramanicus Jalas (TCJ) as a polyphenolic plant has an antiproliferative effect. Accordingly, this investigation studied the TCJ extract anti-tumor effects in a breast cancer model. METHODS: Twenty-four female BALB/c mice were used in 4 groups including (1) breast cancer (control); (2), (3) and (4) breast cancer + 100, 300 and 500 mg/kg of TCJ extract (once daily for 20-days after breast tumor induction). The breast tumour was induced by 4T1 cell carcinoma injection. Then tumor size and weight were measured. Tumor necrosis factor-α (TNF-α), nuclear factor κ-B (NF-κB), interleukin-6 (IL-6) as inflammatory markers and also Bcl-2, Bax, cytosolic cytochrome-c, apoptosis-inducing factor, and cleaved caspase-3 as biochemical apoptosis markers were evaluated in tumor tissue with western blotting analysis. Also, malondialdehyde (MDA) concentration, hydrogen peroxidase (H2O2), catalase, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were exanimated. KEY FINDINGS: Treatment with TCJ extract (500 mg/kg) decreased the tumor volume, tumor weight, GPx, SOD, and catalase enzyme activity versus the control group (P < 0.05). Also, TCJ (500 mg/kg) extract increased MDA, H2O2, inflammatory and apoptosis markers versus control (P < 0.05). CONCLUSIONS: Current study showed that TCJ can induce anti-tumour effects via promoting inflammation, apoptosis, and oxidative stress in breast tumour tissue.

Effects of caloric and time restriction diets on kidney health in rat model of postmenopausal acute kidney injury: An apoptosis and histopathological study.

Objectives: Lifestyle and eating habits affect the health and function of the body's organs, including the kidneys. The current study was carried out to determine the effects of two types of diet programs, including time restriction (TR) and calorie restriction (CR) on the histopathological changes and apoptotic molecules during acute kidney injury (AKI) in postmenopausal rats. Materials and Methods: In this study the female rats were divided into two groups of ovariectomized (OVX) and ovary-intact (sham), then they were placed on TR and CR diets for 8 weeks; afterward, AKI was induced by injection of glycerol. Functional indices, histopathological changes, Bax, and Bcl2 were measured before and after AKI. Results: After AKI, creatinine, serum urea, urinary albumin excretion, kidney tissue Bax, and Bax/Bcl2 ratio increased, while glomerular filtration rate (GFR) and kidney tissue Bcl2 decreased compared with before AKI. Histopathological indices (inflammation, cellular necrosis, cell vacuolization, tubular dilatation, intratubular cast, and congestion) also confirmed renal injury. TR and CR diets improved renal injury indices and prevented an increase in the Bax/Bcl2 ratio. However, in some indices, the effects of two diets on OVX animals were not observed. In addition, none of the diets could decrease kidney weight/body weight ratio (KW/BW). The histopathological finding also showed improvement of renal status in both groups, especially in the CR diet. Conclusion: The results indicated that TR and CR diets had renoprotective effects against AKI by reducing the Bax/Bcl2 ratio and improving apoptosis. The effects of CR were more than TR.

Comparison of the effects of different dietary regimens on susceptibility to experimental acute kidney injury: The roles of SIRT1 and TGF-ß1.

OBJECTIVES: Mortality due to acute kidney injury (AKI) is high despite its reversibility, and studies on efficient treatments for accelerating the recovery of or preventing AKI are of great significance. The amount of daily calorie intake and how it is taken affect body organs and how cells respond to it. The aim of this study was to determine the effects of four types of diets: calorie restriction (CR), time-restriction eating (TR), intermittent fasting (IF), and high-fat diet (HF), on renal injury indicators in male rats. METHODS: Adult rats were placed on CR, TR, IF, and HF diets for 8 wk, after which AKI was induced in them by injection of glycerol. Renal injury indicators and biochemical parameters were measured before and after AKI induction. RESULTS: After AKI, urinary albumin excretion, urea, serum creatinine, and transforming growth factor (TGF)-ß1 increased, whereas creatinine clearance and SIRT1 decreased. CR and TR diets improved renal indicators, decreased TGF-ß1 and malondialdehyde (MDA), and increased SIRT1, total antioxidant capacity, and creatinine clearance after AKI induction. Although IF improved renal indicators, it only led to a decrease in MDA and TGF-ß1. On the other hand, the HF diet worsened renal indicators, increased TGF-ß1, and decreased SIRT1 in the kidney. Moreover, CR and TR improved metabolism indicators, and HF led to the abnormalization of these factors. CONCLUSIONS: The results of the present study showed that CR and TR can be introduced as a treatment method to prevent AKI. These diets can increase the resistance of kidney cells against injuries, possibly by increasing SIRT1, decreasing TGF-ß1, and improving antioxidant status; and they have renoprotective effects.

Substitution of calorie restriction for protective effects of estrogen on cardiometabolic risk factors and oxidative stress in obese postmenopausal rat model.

Estrogen has an anti-obesity effect and plays an important role in improving cardiometabolic disorders. Weight loss and reduction in calorie intake impede the development of obesity-related cardiometabolic risk factors. Therefore, we investigated the substitution of calorie restriction for effects of estrogen on cardiometabolic risk factors and oxidative stress in obese postmenopausal rat model. In this study, adult female Wistar rats were allocated into Sham and ovariectomized (OVX) groups and were given standard diet (SD) or 60% high-fat diet (HFD) or 30% calorie restriction (CR) for 16 weeks, following this, animals received E2 (17-ß estradiol; 1 mg/kg; i.p.) every four days for 4 weeks. Results showed that HFD elevated the body weight, BMI, food intake, and blood glucose (BG) level in both sham and OVX groups. In addition, HFD had negative effects on lipid profile and oxidative stress in these groups. Whereas CR decreased these indices in both Sham and OVX groups fed an HFD, it could not diminish the BG level in the OVX-HFD group. E2 treatment in OVX animals with or without CR reduced body weight, BMI, food intake, and BG level, and also had positive effects on lipid profile alterations and oxidative stress reduction. In comparison, no significant differences were observed regarding the effects of E2 with CR between two groups for body weight, lipid profile, BG, and oxidative stress in the OVX-HFD rats. Overall, CR prevents and ameliorates cardiometabolic risk factors induced by obesity in postmenopausal conditions and is also a good candidate for E2 substitution.

The protective effects of 17-ß estradiol and SIRT1 against cardiac hypertrophy: a review.

One of the major causes of morbidity and mortality worldwide is cardiac hypertrophy (CH), which leads to heart failure. Sex differences in CH can be caused by sex hormones or their receptors. The incidence of CH increases in postmenopausal women due to the decrease in female sex hormone 17-ß estradiol (E2) during menopause. E2 and its receptors inhibit CH in humans and animal models. Silent information regulator 1 (SIRT1) is a NAD+-dependent HDAC (histone deacetylase) and plays a major role in biological processes, such as inflammation, apoptosis, and oxidative stress responses. Probably SIRT1 because of these effects, is one of the main suppressors of CH and has a cardioprotective effect. On the other hand, estrogen and its agonists are highly efficient in modulating SIRT1 expression. In the present study, we review the protective effects of E2 and SIRT1 against CH.

Estrogen receptor agonists induce anti­edema effects by altering α and ß estrogen receptor gene expression.

The present study aimed to examine whether the attenuation of estrogen receptor expression is prevented by propyl pyrazole triol (PPT), an agonist for estrogen receptor α (ERα) or and diarypropiolnitrile (DPN), an agonist for estrogen receptor ß (ERß) after traumatic brain injury (TBI). The tests performed on ovariectomized female Wistar rats included sham group, vehicle group, and treated groups: PPT, DPN, and PPT+DPN 30 minutes after TBI. Blood­brain barrier (BBB) disruption and brain water content were estimated. RT­PCR and\r\nwestern blotting were utilized to evaluate ESR1 and ESR2 gene and protein expression. The data indicated that PPT, DPN, and PPT+DPN attenuated TBI­induced brain edema. Also, BBB disruption after TBI was prevented in PPT, DPN, and PPT+DPN­treated TBI animals. Estrogen agonist­treated animals showed a significant elevation in Esr1 mRNA and protein expression levels in the brain tissue of TBI rats. In addition, the data indicated a significant elevation of Esr2 mRNA and protein expression levels in the brain tissue of estrogen agonist­treated TBI rats. The data shows that both ESR1 and ESR2 agonists can enhance ER mRNA and protein levels in TBI animals' brain. It appears that this effect contributes to the neuroprotective function of ER agonists.

Activators of SIRT1 in the kidney and protective effects of SIRT1 during acute kidney injury (AKI) (effect of SIRT1 activators on acute kidney injury).

Acute kidney injury (AKI) is a complex disorder and a clinical condition characterized by acute reduction in renal function. If AKI is not treated, it can lead to chronic kidney disease, which is associated with a high risk of death. SIRT1 (silent information regulator 1) is an NAD-dependent deacetylase. This enzyme is responsible for the processes of DNA repair or recombination, chromosomal stability, and gene transcription. This enzyme also plays a protective role in many diseases, including AKI. In this study, we review the mechanisms that mediate the protective effects of SIRT1 on AKI, including SIRT1 activators.

Anticancer and cytotoxic effects of troxerutin on HeLa cell line: an in-vitro model of cervical cancer.

Cervical cancer is one of the grave uterine tumors which leads to death in women worldwide. Troxerutin (TRX) as a bioflavonoid compound has many pharmacological effects such as anti-neoplastic, radioprotective, and anti-cancer. The present study was designed to examine the cytotoxic effect of TRX on human HeLa tumor cells. Human HeLa cells were cultured and treated with different doses of TRX (20-640 mg/ml) to evaluate the effective half-maximal inhibitory concentration (IC50) after 24 h. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test was used for cell proliferation assay. Also, the Bax, Bcl-2, cleaved caspase-3, and tumor necrosis factor-α (TNF-α) protein expression levels were detected with immunoblotting analysis. The malondialdehyde (MDA) concentration, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity levels were measured via their commercial kits. Data were analyzed using one-way ANOVA. The result showed that TRX at 320 mg/ml concentration (IC50) has a growth inhibitory effect against HeLa cells at 24 h treatment (P ˂ 0.01). Moreover, it increased the MDA concentration and also decreased the GPx and SOD activity levels at 320 mg/ml concentration versus control (P < 0.001). Also, TRX significantly up-regulated the Bax, cleaved caspase-3 and TNF-α proteins expression levels (P  < 0.01) and down-regulated the Bcl-2 protein expression in HeLa tumor cells at 320 mg/ml concentration compared to control (P < 0.05). Our study showed that 24 h of treatment with TRX (320 mg/ml) has apoptotic and growth inhibitory effects against HeLa cells. It can induce inflammation (at least via up-regulating the TNF-α protein expression) and oxidative stress in human HeLa cells.

Neuroprotective and antinociceptive effects of rosemary (Rosmarinus officinalis L.) extract in rats with painful diabetic neuropathy.

Diabetes mellitus is associated with the development of neuronal tissue damage in different central and peripheral nervous system regions. A common complication of diabetes is painful diabetic peripheral neuropathy. We have explored the antihyperalgesic and neuroprotective properties of Rosmarinus officinalis L. extract (RE) in a rat model of streptozotocin (STZ)-induced diabetes. The nociceptive threshold and motor coordination of these diabetic rats was assessed using the tail-flick and rotarod treadmill tests, respectively. Activated caspase-3 and the Bax:Bcl-2 ratio, both biochemical indicators of apoptosis, were assessed in the dorsal half of the lumbar spinal cord tissue by western blotting. Treatment of the diabetic rats with RE improved hyperglycemia, hyperalgesia and motor deficit, suppressed caspase-3 activation and reduced the Bax:Bcl-2 ratio, suggesting that the RE has antihyperalgesic and neuroprotective effects in this rat model of STZ-induced diabetes. Cellular mechanisms underlying the observed effects may, at least partially, be related to the inhibition of neuronal apoptosis.

Leptin attenuates oxidative stress and neuronal apoptosis in hyperglycemic condition.

One of the main pathological mechanisms of neurotoxicity in diabetic situation is oxidative stress promoted by hyperglycemia. It has been shown that leptin has neuroprotective effects and may provide neuronal survival signals. This study was designed to reveal the possible neuroprotective effects of leptin in hyperglycemic conditions. Pheochromocytoma (PC12) cell viability was assessed via the MTT test. Cellular reactive oxygen species (ROS) generation was determined by DCFH-DA analysis. The malondialdehyde (MDA) and glutathione (GSH) levels were measured in high-glucose-treated PC12 cells with and without leptin cotreatment. Western blotting was performed to measure apoptosis markers (Cleaved caspase-3 and Bax/Bcl2 ratio). Elevation of glucose levels (100 mmol/L) consecutively increased intracellular ROS and MDA level, and apoptosis in PC12 cells after 24 h leptin administration (12 and 24 nmol/L) decreased the high-glucose-induced cell toxicity, caspase-3 activation, and Bax/Bcl-2 ratio. Also, cotreatment with leptin (12 and 24 nmol/L) significantly reduced oxidative damage to PC12 cells in high-glucose condition, as reflected by the diminution in MDA and ROS levels and the increase in GSH content. Our finding demonstrates that leptin has protective effects against hyperglycemia-induced neural damage. This could be related to the attenuation of oxidative stress and neural apoptosis.

Neuroprotective and antihyperalgesic effects of orexin-A in rats with painful diabetic neuropathy.

AIM OF STUDY: Diabetes mellitus is related to the development of neuronal tissue injury in different peripheral and central nervous system regions. A common complication of diabetes is painful diabetic peripheral neuropathy (PDN). We have studied the neuroprotective and anti-nociceptive properties of neuropeptide orexin-A in an animal experimental model of diabetic neuropathy. METHODS: All experiments were carried out on male Wistar rats (220-250 g). Diabetes was induced by a single intraperitoneal injection of 55 mg/kg (i.p.) streptozotocin (STZ). Orexin-A was chronically administrated into the implanted intrathecal catheter (0.6, 2.5 and 5 nM/L, daily, 4 weeks). The tail-flick and rotarod treadmill tests were used to evaluate the nociceptive threshold and motor coordination of these diabetic rats, respectively. Cleaved caspase-3, Bax, Bcl2 and the Bax/Bcl-2 ratio, as the biochemical indicators of apoptosis, were investigated in the dorsal half of the lumbar spinal cord tissue by western blotting method. RESULTS: Treatment of the diabetic rats with orexin-A (5 nM/L) significantly attenuated the hyperalgesia and motor deficit in diabetic animals. Furthermore, orexin-A (5 nM/L) administration suppressed pro-apoptotic cleaved caspase-3 and Bax proteins. Also, orexin-A (5 nM/L) reduced the expression of Bax/Bcl-2 ratio in spinal cord dorsal half of rats with PDN. CONCLUSIONS: Altogether our data suggest that the orexin-A has anti-hyperalgesic and neuroprotective effects in rats with PDN. Cellular mechanisms underlying the observed effects may, at least partially, be related to reducing the neuronal apoptosis.

Cellular Preoxygenation Partially Attenuates the Antitumoral Effect of Cisplatin despite Highly Protective Effects on Renal Epithelial Cells.

Our previous in vitro studies demonstrated that oxygen pretreatment significantly protects human embryonic renal tubular cell against acute cisplatin- (CP-) induced cytotoxicity. The present study was designed to investigate whether this protective effect is associated with decreasing therapeutic effects of cisplatin on malignant cells. For this purpose, cultured human embryonic kidney epithelial-like (AD293), cervical carcinoma epithelial-like (Hela), and ovarian adenocarcinoma epithelial-like (OVCAR-3) cells were subjected to either 2-hour pretreatment with oxygen (≥90%) or normal air and then to a previously determined 50% lethal dose of cisplatin for 24 hours. Cellular viability was evaluated via MTT and Neutral Red assays. Also, activated caspase-3 and Bax/Bcl-2 ratio, as the biochemical markers of cell apoptosis, were determined using immunoblotting. The hyperoxic preexposure protocol significantly protects renal AD293 cells against cisplatin-induced toxicity. Oxygen pretreatment also partially attenuated the cisplatin-induced cytotoxic effects on Hela and OVCAR-3 cells. However, it did not completely protect these cells against the therapeutic cytotoxic effects of cisplatin. In summary, the protective methods for reducing cisplatin nephrotoxic side effects like oxygen pretreatment might be associated with concurrent reduction of the therapeutic cytotoxic effects of cisplatin on malignant cells like cervical carcinoma (Hela) and ovarian adenocarcinoma (OVCAR-3) cells.

Effects of sex steroid hormones on neuromedin S and neuromedin U2 receptor expression following experimental traumatic brain injury.

OBJECTIVES: Neuroprotective effects of female gonadal steroids are mediated through several pathways involving multiple peptides and receptors after traumatic brain injury (TBI). Two of these peptides are including the regulatory peptides neuromedin U (NMU) and neuromedin S (NMS), and their common receptor neuromedin U2 receptor (NMUR2). This study investigates the effects of physiological doses of estradiol and progesterone on brain edema, NMS and NMU as well as NMUR2 expression following TBI. MATERIALS AND METHODS: Ovariectomized female rats were given high-and low-dose of female sex steroid hormones through implantation of capsules for a week before trauma. The brain NMUR2 expression, prepro-NMS expression, NMU content, and water content (brain edema) were evaluated 24 hr after TBI induced by Marmarou's method. RESULTS: Percentage of brain water content in high- and low-dose estradiol, and in high- and low- dose progesterone was less than vehicle (P<0.01). Results show high expression of prepro-NMS in high dose progesterone (TBI-HP) rats compared to the high dose estrogen (TBI-HE), as well as vehicle (P<0.01). NMU content in low-dose progesterone (TBI-LP) group was more than that of vehicle group (P<0.001). Furthermore a difference in NMU content observed between TBI-HP compared to TBI-HE, and vehicle (P<0.05). The NMUR2 mRNA expression revealed an upregulation in TBI-HP rats compared to the TBI-HE group (P<0.001). CONCLUSION: Findings indicate that progesterone attenuates brain edema and induces an increase in NMS and its receptor which may mediate the anti-edematous effect of progesterone after TBI.

Noxious Stimulation of the Rat Tooth Pulp May Impair Learning and Memory Through the Induction of Hippocampal Apoptosis.

AIMS: To determine whether noxious stimulation of the rat tooth pulp induces learning and memory impairment through the induction of apoptosis in the hippocampus. METHODS: Thirty-five adult rats were divided randomly into five groups (each n=7) as follows: control, sham-operated, sham-vehicle, capsaicin-treated, and capsaicin plus ibuprofen-treated group. After preparing dental cavities via cutting 2 mm of the distal extremities of the mandibular incisors, polyethylene crowns were placed on the teeth. Based on the study groups, different injections were administered into the cavities. Nociceptive scores for each block were obtained by measuring the number of seconds that the animal spent rubbing and flicking the lower jaw. After recording the nociceptive behaviors, spatial learning and memory were assessed by using the Morris Water Maze (MWM) test. The hippocampal levels of Bcl-2, Bax, and caspase-3 protein were determined by immunoblotting. Statistical analyses were performed using one- or two-way analysis of variance. RESULTS: Noxious pulp stimulation induced by intradental application of capsaicin significantly increased time and traveled distance in the MWM test. Capsaicin stimulation of the pulp also significantly increased the Bax:Bcl-2 ratio and activated caspase-3 in the hippocampus (P<.01), which was inhibited by ibuprofen pretreatment (P<.05). CONCLUSION: Memory and learning impairment induced by noxious stimulation of the rat tooth pulp may be correlated with activation of apoptotic pathways in the hippocampus.

Aqueous extract of Zizyphus jujuba fruit attenuates glucose induced neurotoxicity in an in vitro model of diabetic neuropathy.

OBJECTIVES: The neuroprotective effect of fruit aqueous extract of Ziziphus jujuba Lam on glucose-induced neurotoxicity in PC12 cells as an appropriate in vitro model of diabetic neuropathy was investigated. MATERIALS AND METHODS: Cell viability was determined by the MTT assay. Cellular reactive oxygen species (ROS) generation was measured by DCFH-DA analysis. Cleaved caspase-3, a biochemical parameter of cellular apoptosis, was measured by western blot analysis. RESULTS: Our data showed that a 4-fold elevation in glucose levels within the medium significantly reduced cell viability, increased intracellular ROS and caspase-3 activation in PC12 cells after 24 hr. Incubation of the high glucose medium cells with 300-µg/ml Z. jujuba fruit (ZJF) extract decreased the high glucose-induced cell toxicity and prevented caspase-3 activation and excited ROS generation. CONCLUSION: Thus, we concluded that the aqueous extract of Z. jujuba protects against hyperglycaemia-induced cellular toxicity. This could be associated with the prevention of ROS generation and neural apoptosis. Moreover, the results suggest that the ZJF has a therapeutic potential to attenuate diabetes complications such as neuropathy.

Changes in the gene expression of estrogen receptors involved in the protective effect of estrogen in rat's trumatic brain injury.

It has been demonstrated that estradiol has neuroprotective effects after traumatic brain injury (TBI) in female rats. Since estrogen receptors have an important role in estradiol effects at the cellular level and the exact mechanism(s) of estradiol-induced neuroprotection has not yet been fully clarified, the present study was designed to determine the changes in the levels of estrogen receptors mRNAs and proteins involved in this phenomenon. All experiments were carried out on female Wistar rats. The brain edema and blood-brain-barrier (BBB) disruption were assessed. The TBI method was diffuse type and induced by the Marmarou method. Semiquantitative RT-PCR and immunoblotting were used to assess ERα and ERß gene expression. The data showed that the level of brain water content was significantly increased in TBI group. The increased water content was significantly attenuated in estradiol-treated (1mg/kg) TBI rats. Disruption of BBB after TBI was significantly inhibited just by estradiol treatment. Estrogen-treated animals showed a significant increase in ERα mRNA (18%) and protein (35%) levels in the brain tissue. Furthermore, in the brain-injured rats the levels of ERß mRNA were lower than those in control rats. Following estrogen treatment, the protein levels of ERß were closed to those in control group. In conclusion, the data demonstrate that estrogen treatment can protect brain against traumatic brain injury. Estrogen treatment increases ER mRNA and protein levels which were coincident with its protective effects. It seems that such phenomenon participates in the induction of neuroprotective effects of estrogen. This article is part of a Special Issue entitled 1618.