Iranian Journal of Basic Medical Sciences
Year:2014 | Volume:17 | Issue:1|Papers Count:12

Objective(s): The effect of prolonged overtraining on cytokine kinetics was compared with moderate exercise in the present study.Materials and Methods: Male Wistar rats were randomly divided into control sedentary (C), moderate trained (MT), (V=20 m/min, 30 min/day for 6 days a week, 8 weeks), overtrained (OT) (V=25 m/min, 60min/day for 6 days a week, 11 weeks) and recovered overtrained (OR) (OT plus 2 weeks recovery) groups, (n=6 for each group). Immediately, 24 hr and 2 weeks (in OR) after last bout of exercise blood samples were obtained. The plasma concentrations of TNFa, IL-6, IL-10, IL-4 and IFNg were measured by ELISA method.Results: Immediately after last bout of exercise the following findings were observed; IL-6, IL-10 and TNFαconcentrations increased in OT and OR groups compared with control (P<0.05– P<0.001). Serum level of IL-4 decreased (P<0.01) but IFNg increased (P<0.05) in MT group vs. control. In addition, circulatory levels of TNFa IL-6, IL-10 and IL-4 were higher but the IFNg concentrations were lower in OT and OR groups than MT group (P<0.05- P<0.01). The IFN-gIL4 ratio was significantly increased in MT (P<0.01) while it decreased in OT group. There were not statistical differences in TNFa IL-6, and IFNg levels between different time intervals after exercise in MT, OT and OR groups.Conclusion: These data confirm a positive effect of moderate exercise on immune function and a decrease in susceptibility to viral infection by inducing Th1 cytokine profile shift. However, prolonged and overtraining exercise causes numerous changes in immunity that possibly reflects physiological stress and immune suppression.

Objective(s): In this study, the effects of chronic administration of crocin, an active constituent of saffron, on blood pressures of normotensive and desoxycorticosterone acetate (DOCA) - salt induced hypertensive rats, were investigated.Materials and Methods: Five week administration of three doses of crocin (50, 100 and 200 mg/kg/day) and spironolactone (50 mg/kg/day) in different groups of normotensive and hypertensive rats (at the end of 4 weeks treatment by DOCA-salt) was carried out and their effects on mean systolic blood pressure (MSBP) and heart rate (HR) were evaluated using tail cuff method. The duration of effect of crocin on SBP, was also evaluated.Results: Our results indicated that chronic administration of crocin could reduce the MSBP in DOCA salt treated rats in a dose dependent manner. Crocin did not decrease the MSBP in normotensive rats. The data also showed that antihypertensive effects of crocin did not persist.Conclusion: It is concluded that crocin possesses antihypertensive and normalizing effect on BP in chronic administration.

Objective(s): The aim of this study was to insert nitrofurazone in a chitosan membrane to be used as a wound dressing.Materials and Methods: Several blend films using chitosan (Cs) and polyvinyl alcohol (PVA), containing nitrofurazone were prepared by means of casting/solvent evaporating technique. Different characteristics such as mechanical properties, water vapor transmission rate (WVTR), oxygen permeability (OP), swelling ability (SW), differential scanning calorimetric (DSC), drug release profiles and antibacterial activity of the films were investigated.Results: The results showed that nitrofurazone decreased tensile strength, OP and SW of Cs films, while increased WVTR. Addition of PVA at any concentration improved mechanical properties, reduced WVTR, and increased OP and SW of nitrofurazone-loaded Cs films. The latter films showed higher activity against Pseudomonas aeruginosa than drug-free chitosan films.Conclusion: The presence of PVA improves many properties of Cs-nitrofurazone films and makes them more desirable as dressing material for burn wounds. Although nitrofurazone alone is ineffective against P. aeruginosa, it is able to increase antibacterial effect of chitosan in composite films

Objective(s): To date, the most important genes responsible for tetracycline resistance among Acinetobacter baumannii isolates have been identified as tet A and tet B. This study was carried out to determine the rate of resistance to tetracycline and related antibiotics, and mechanisms of resistance.Materials and Methods: During the years 2010 and 2011, a total of 100 A. baumannii isolates were recovered from patients in different hospitals of Tehran, Iran. Antimicrobial susceptibility to tetracycline, minocycline, doxicycline and tigecycline was evaluated by E-test. Polymerase chain reaction (PCR) of the tet A and tet B genes was performed using specific primers, after which the isolates were subjected to Repetitive Extragenic Palindromic-PCR (PCR) to identify the major genotypes.Results: Of all isolates, 89% were resistant to tetracycline (MIC50 = 32 mg/ml, MIC90 = 512 mg/ml). Minocycline with the resistant rate of 35% (MIC50 = 16 mg/ml, MIC90 =32 mg/ml) and doxicycline with the resistant rate of 25% (MIC50 = 16 mg/ml, MIC90= 32 mg/ml) have a good activity against A. baumannii isolates. All isolates were sensitive to tigecycline. Frequencies of tet B and tet A genes and coexistence of tet A and tet B among the isolates resistant to tetracycline, were 87.6%, 2.2% and 1.1%, respectively. Distribution of REP-types among A. baumannii isolates was types A (40%), B (30%), C (10%), D (5%) and E (5%).Conclusion: It seems that tet A and tet B genes play an important role in the induction of resistance towards tetracyclines used in this study. It is suggested that further studies focus on other antimicrobial drugs and combinations in order to achieve a successful therapy against multi drug resistance (MDR) A. baumannii strains in Iran.

Objective(s): Stem cell therapy is believed to be as a promising treatment strategy for tissue repair and regeneration. The plasticity specification of the adult stem cells, such as MSCs, has enabled that these cells to be used in the treatment of a broad spectrum of diseases like liver disorders. In this study, the production of urea and Albumin (Alb), glycogen storage, and expression of some liver genes including α-fetoprotein (AFP), Alb, cytokeratin18 (CK18) and cytokeratin19 (CK19) was compared between mesenchymal stem cells (MSCs) and isolated rat hepatocytes.Materials and Methods: The MSCs were isolated from rat femurs and tibias and cultured in α-MEM, DMEM and RPMI mediums supplemented with serum. Hepatocytes were isolated from Rat livers and cultured in DMEM with serum. The expression of AFP, Alb, CK18, and CK19 genes was evaluated using the reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, the synthesis of albumin and urea of the cells was measured.Results: In vitroconditions, MSCs and hepatocytes exhibited the characteristic functions of the liver such as capacity to synthesize Alb, urea, the storage of glycogen. In this study, the expression of some liver genes such as AFP, Alb, CK18 and CK19 at mRNA levels was also shown.Conclusion: The results showed that MSCs exhibited some liver functions, and may be considered as an alternative source for adult stem cell transplantation in liver repair due to the excellent proliferation and differentiation capacities.

Objective(s): Stress induces many homeostatic aberrations which are followed by lifelong allostatic responses. Epilepsy is developed or influenced by different environmental factors, i.e. prenatal stress which makes many contradictory developmental changes in seizure threshold and intensity. We investigated the potential seizure response of the rat offspring to prenatal stress; the stress which was applied to their mothers.Materials and Methods: Nine day heterogeneous sequential stress (HSS) model was used before and during the first and before the second pregnancy. The kindling was induced using 13 IP injections of pentylenetetrazol (PTZ) every 48 hr to adult male Wistar rat's offspring.Results: The results of the present study demonstrated that, before pregnancy stress decreased the rate of kindling (P<0.05) in the offspring, while stress which was applied during pregnancy completely prevented kindling (P<0.001). Further, their convulsive latency was increased and tonic clonic seizure duration was decreased. In contrast, previous pregnancy and between pregnancies stress could not change kindling process. Although maternal separation stress did not change kindling development, it could increase convulsive intensities by elongating the duration of seizures (P<0.05) and reducing convulsion latency (P<0.05).Conclusion: It is concluded that stress detrimental effects could be prevented by stress which was applied around first pregnancy; however this beneficial effect is weakened by before second pregnancy stress.

Objective(s): Leptin is a hormone secreted by adipose tissue and is involved not only in the regulation of feeding and energy expenditure, but also its role in memory enhancement has been demonstrated as well. The partial transfer of leptin across the blood-brain barrier in obese individuals causes leptin resistance and prevents leptin reaching brain. On the other hand, studies have shown that angiotensin antagonists such as losartan can improve memory and learning abilities. The aim of this study was to evaluate the effects of losartan on improving memory and leptin resistance induced by high fat diet in obese rats.Materials and Methods: 40 Wistar male rats were divided in 4 groups: control (C), losartan (LOS), high-fat diet (HFD) and high-fat diet and losartan (HFD and LOS). The spatial memory performances of the rats were assessed in the Morris water maze after 2 months of treatment. Then they were weighed and serum levels of leptin and triglyceride were measured.Results: In spite of receiving high-fat diet, no significant differences in body weight were observed in the (HFD & LOS) group. In the Morris water maze trial, the (LOS) and (HFD & LOS) groups also showed a significant reduction (P<0.05) in latency and path length. In addition, a significant decrease (P <0.05) in serum levels of leptin and no significant difference in serum levels of triglyceride was observed in the (HFD & LOS) group.Conclusion: Losartan can improve leptin resistance induced by obesity and high fat diet. At the same time, it modulates body weight and enhances learning and memory.

Objective(s): HTLV-I and HIV virus quantification is an important marker for assessment of virus activities. Since there is a direct relationship between the number of virus and disease progression, HTLV-I and HIV co-infection might have an influence on the development of viral associated diseases, thus, viral replication of these viruses and co-infection were evaluated.Materials and Methods: In this study, 40 subjects were selected; 14 HIV infected, 20 HTLV-I infected and 6 HTLV-I/HIV co-infected subjects. The amount of viruses was measured using qPCR TaqMan method and CD4 and CD8 lymphocytes were assessed by flow cytometry.Results: The mean viral load of HIV infected subjects and HTLV-I infected individuals were 134626.07±60031.07 copies/ml and 373.6±143.3 copies/104 cells, respectively. The mean HIV viral load in co-infected group was 158947±78203.59 copies/ml which is higher than HIV infected group. The mean proviral load of HTLV-I in co-infected group was 222.33±82.56 copies/ml which is lower than HTLV-I infected group (P<0.05). Also, the mean white blood cell count was higher in co-infected group (5666.67±1146.49 cells/ml). However, the differences between these subjects did not reach to a statistical significance within 95% confidence interval level (P =0.1). No significant differences were observed regarding CD4 and CD8 positive lymphocytes between these groups.Conclusion: HTLV-I/HIV co-infection might promote HIV replication and could reduce the HTLV-I proviral load, in infected cells. Considering the presence of both viruses in Khorasan provinces, it encourages researchers and health administrators to have a better understanding of co-infection outcome.

Objective(s): The present study investigated the effects of microinjection of histamine and histamine H1, H2, and H3 receptor antagonists, chlorpheniramine, ranitidine and thioperamide, respectively into the primary somatosensory cortex (PSC) on inflammatory pain.Material and Methods: Two stainless steel guide canulas were bilaterally implanted into the PSC of anaesthetized rats. Inflammatory pain was induced by subcutaneous (SC) injection of formalin (50 ml, 2.5%) in the ventral surface of right hind paw. Time durations of licking/biting of the injected paw were recorded as a pain measure.Results: Formalin produced a biphasic pattern of licking/biting of the injected paw. Histamine at doses of 0.5, 1, and 2 mg decreased the intensity of pain. Chlorpheniramine and ranitidine at the same doses of 1 and 4 mg had no effects, whereas thioperamide at a dose of 4 mg suppressed both phases of formalin-induced pain. Pretreatments with chlorpheniramine and ranitidine at the same dose of 4 mg prevented histamine (2 mg)-induced antinociception. Antinociceptive effects were observed when thioperamide at doses of 1 and 4 mg was used with 0.25 and 1 mg of histamine, respectively. The antinociceptive effects induced by histamine (2 mg) and thioperamide (4 mg) were prevented by prior treatment with naloxone (4 mg).Conclusion: These results indicate that at PSC levels, histamine through post-synaptic H1, H2, and pre-synaptic H3 receptors might be involved in pain modulation. The endogenous opioid system may be involved in histamine- and thioperamide-induced antinociception.

Objective(s): Studies have reported that whole body vibration (WBV) played a vital role in bone remodeling. Circulating serotonin is also involved in negative regulating bone mass in rodents and humans. However, both WBV and inhibition of serotonin biosynthesis may suppress receptor activator of nuclear factor-kappaB ligand (RANKL)-induced osteoclastogenesis in vitro. The purpose of the current study was to investigate the effect of WBV therapy on the levels of serum serotonin in ovariectomized rats.Materials and Methods: Thirty-six-month-old female Sprague Dawley rats weighing 276.15±37.75 g were ovariectomized to induce osteoporosis, and another ten rats underwent sham operation to establish sham control (SHAM) group. After 3 months, ovariectomized rats were divided into three subgroups and then separately treated with WBV, Alendronate (ALN) and normal saline (OVX), SHAM group was given normal saline. After 6 weeks of treatment, rats were sacrificed. Serum serotonin, RANKL, bone turnover markers, and bone mineral density (BMD), bone strength were evaluated.Results: The serum serotonin level was significantly lower in WBV group than OVX and ALN groups (P<0.05 and P<0.001). RANKL levels significantly decreased in WBV and ALN groups compared to OVX group (P<0.001 for both). BMD and biomechanical parameters of femur significantly increased (P<0.05 for both) and bone turnover levels decreased (P<0.001 for both) in WBV group compared to OVX group.Conclusion: These data indicated that WBV enhanced the bone strength and BMD in ovariectomized rats most likely by reducing the levels of circulating serotonin.

Objective(s): Because of the high total phenolic contents of Feijoa sellowiana, its nephroprotective effect was determined in 3,4-methylene dioxymethamphetamine (MDMA) treated mice.Materials and Methods: Animals received 10, 20 and 40 mg/kg doses of aqueous or methanol extract of F. sellowiana leaves, intra-peritoneally. After one hour, an acute administration of MDMA (20 mg/kg, IP) was injected. Nephroprotective effect was assayed by determination of serum creatinine, serum urea and kidney glutathione level. Histopathological study was also used.Results: Both extracts at 40 mg/kg resulted in a significant reversal in the raised serum creatinine levels (P<0.05). Not statistically significant was observed in effect of two extracts (P>0.05). A decrease in urea/ creatinine ratio was observed following aqueous extract treatment. Methanolic extract showed higher activity in increasing kidney glutathione (P<0.001 compared to MDMA group). Methanol extract showed higher protective activity in histopathology study.Conclusion: F. sellowiana extract resulted in a markedly decrease in the nephrotoxicity of MDMA in mice.

Objective(s): To appraise the antihepatotoxic efficacy of ethanolic extract of Operculum turpethum root on the liver of Swiss albino mice.Materials and Methods: Hepatic fibrosis was induced in adult male albino mice through intraperitoneal administrations of N-nitrosodimethylamine (NDMA) at the concentration of 10 mg/kg body weight. The liver toxicity and therapeutic effect of the plant ethanolic extract was assessed by the analysis of liver marker enzymes and antioxidant enzymes and liver histopathological studies.Results: Hepatotoxicity was manifested by significantly decreased (P<0.01) levels of the activities of the enzymatic and non enzymatic antioxidants such as superoxide dismutase, catalase, GSH and increased levels of cholesterol, AST, ALT, ALP and lipid peroxidation. The plant extract significantly restored the antioxidant enzyme level in the liver and exhibited significant dose dependent curative effect against NDMA induced toxicity which was also supported by histopathological studies of the liver.Conclusion: O. turpethum manifested therapeutic effects by significantly restoring the enzymatic levels and reducing the hepatic damage in mice. This work intends to aid researchers in the study of natural products which could be useful in the treatment of liver diseases including cancer.