Venlafaxine inhibits naloxone-precipitated morphine withdrawal symptoms: Role of inflammatory cytokines and nitric oxide

Metabolic Brain Disease - Opioid-induced neuroinflammation plays a role in the development of opioid physical dependence. Moreover, nitric oxide (NO) has been implicated in several oxidative and...     

Sildenafil enhances the peripheral antinociceptive effect of ellagic acid in the rat formalin test

Objective:

Ellagic acid (EA), a major polyphenolic compound of pomegranate juice, produces antinociceptive effects, which are mediated through opioidergic and nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathways. The present study was conducted to elucidate the peripheral antinociceptive effect of EA alone and in combination with sildenafil in the rat formalin test.

Materials and Methods:

Pain was produced by intraplantar injection of formalin (2.5%) in rats and nociceptive behavior was measured as the number of flinches every 5 min in 60 min after injection.

Results:

Local administration of EA and sildenafil dose-dependently increased the nociception threshold in both phases of the test. Moreover, sub-effective doses of sildenafil (25 or 50 mcg/paw, i.p.) significantly and dose-dependently enhanced the antinociception induced by a sub-effective dose of EA (60 mcg/paw, i.pl.) in both phases of the test. The antinociception produced by these drugs alone, or in combination, was due to a peripheral site of action, since the administration in the contralateral paw was ineffective.

Conclusion:

Our results suggest that EA has local peripheral antinociceptive activity, and enhancement of this effect with sildenafil probably occurs through the inhibition of cGMP metabolism.KEY WORDS: Ellagic acid, formalin, peripheral antinociception, sildenafil     

A study of the mechanisms underlying the anti-inflammatory effect of ellagic acid in carrageenan-induced paw edema in rats

Objectives:Ellagic acid (EA) has shown antinociceptive and anti-inflammatory effects. Inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2) enzymes and also cytokines play a key role in many inflammatory conditions. This study was aimed to investigate the mechanisms involved in the anti-inflammatory effect of EA.Results:The results showed that intraplantar injection of carrageenan led to time-dependent development of peripheral inflammation, which resulted in a significant increase in the levels of tumor necrosis factor α (TNF-α) and interleukin 1 (IL-1) β, nitric oxide (NO) and prostaglandin E₂ (PGE₂) and also iNOS and COX-2 protein expression in inflamed paw. However, systemic administration of EA (1–30 mg/kg, intraperitoneal [i.p.]) could reduce edema in a dose-dependent fashion in inflamed rat paws with ED50 value 8.41 (5.26–14.76) mg/kg. It decreased the serum concentration of NO, PGE₂, aspartate aminotransferase and alanine aminotransferase, and suppress the protein expression of iNOS, COX-2 enzymes, and attenuated the formation of PGE_2, TNF-α and IL-1 β in inflamed paw tissue. We also demonstrated that EA significantly decreased the malondialdehyde (MDA) level in liver at 5 h after carrageenan injection. Moreover, histopathological studies indicated that EA significantly diminished migration of polymorphonuclear leukocytes into site of inflammation, as did indomethacin.Conclusions:Collectively, the anti-inflammatory mechanisms of EA might be related to the decrease in the level of MDA, iNOS, and COX-2 in the edema paw via the suppression of pro-inflammatory cytokines (TNFα, IL1 β), NO and PGE₂ overproduction.KEY WORDS: Carrageenan, ellagic acid, inducible nitric oxide synthase, prostaglandin E₂, Rat     

Topical vitamin K1 promotes repair of full thickness wound in rat

Objectives:

Application of vitamin K to the skin has been used for suppression of pigmentation and resolution of bruising. However, in rats, no study was reported on its effect regarding wound healing. Thus, the present study was designed to examine the healing effects of creams prepared from vitamin K₁ on full-thickness wound in rats.

Materials and Methods:

For inducing full-thickness wound in rats, the excisional wound model was used. Five groups consisting of 8 rats each were used. Vitamin K cream (1% and 2%, w/w) was prepared in eucerin base and applied on the wound once a day until complete healing had occurred. Healing was defined by decreased wound margin (wound contraction), re-epithelialization, tensile strength and hydroxyproline content. Histopathological examination was also done.

Results:

The effects produced by the topical vitamin K showed significant (P < 0.01) healing when compared with control group in parameters such as wound contraction, epithelialization period, hydroxyproline content and tensile strength. Histopathological studies also showed improvement with vitamin K.

Conclusions:

Topical vitamin K demonstrates wound healing potential in full-thickness wound model.KEY WORDS: Excision, rat, vitamin K₁, wound healing     

Comparison of Molecular,Microscopic, and Culture Methods for Diagnosis of Cutaneous Leishmaniasis

Cutaneous leishmaniasis (CL) is endemic in the northwest of Isfahan province, Iran. Increase in the incidence of the disease in Kashan has made it necessary to find out the best method for diagnosis and molecular characterization of Leishmania species. In the present study, 130 patients suspected to cutaneous leishmaniosis referred to health care centers of Kashan were examined. Serosity of lesion was collected for smear preparation and cultured in Novy‐Nicolle‐McNeal medium. DNA was extracted from serosity, and Leishmania species was determined by polymerase chain reaction (PCR) and nested PCR using kinetoplast DNA (kDNA) specific primers. The diagnostic criteria of CL were based on the observation of amastigotes in the smear, promastigotes in culture, presence of expected bands in PCR, or nested PCR. Of 130 specimens, 87 (66.9%), 72 (56.2%), 98 (75.4 %), 96 (73.8%), and 99 (76.2%) were positive for microscopic culture, PCR, nested PCR, and combined PCR and microscopy (proposed method), respectively. Sensitivity, specificity, positive and negative predictive values of PCR were 99%, 100%, 100%, 96.9%, respectively, for microscopy 87.9%, 100%, 100%, 72.1%, for culture 72.7%, 100%, 100%, 53.4 %, and for nested PCR 97%, 100%, 100%, 91.2%, respectively. Based on the results of the study, kDNA‐PCR was the most sensitive method for diagnosis of CL.     

Ellagic acid enhances the antinociceptive action of carbamazepine in the acetic acid writhing test with mice

Context: Ellagic acid (EA) produced antinociceptive and anti-inflammatory effects through the central and peripheral sites of action.

Objective: The objective of the current study was to examine the functional interaction between ellagic acid and carbamazepine (CBZ) on pain.

Materials and methods: Fourteen groups of mice (8–10 each) were used in this study. Pain was induced by intraperitoneal acetic acid in mice (writhing test) and the functional interaction was analyzed using the isobolographic method. EA at doses 0.3, 1, 3, and 10?mg/kg and carbamazepine at doses 3, 10, 20, and 30?mg/kg, alone and also in combination (1/2, 1/4, and 1/8 of the drug’s ED₅₀) were intraperitoneally administered 30?min before acetic acid (0.6% v/v). Then, the abdominal writhes were counted during a 25-min period.

Results: EA (0.3–10?mg/kg, i.p.) and CBZ (3–30?mg/kg, i.p.) inhibited the writhing response evoked by acetic acid. Fifty percent effective dose (ED₅₀) values against this tonic pain were 1.02?mg/kg and 6.40?mg/kg for EA and CBZ, respectively. The antinociception induced by EA showed higher potency than that of carbamazepine. Co-administration of increasing fractional increments of ED₅₀ values of EA and CBZ produced additive interaction against writhing responses, as revealed by isobolographic analysis.

Discussion and conclusion: These results suggest that a combination of carbamazepine and ellagic acid may be a new strategy for the management of neuropathic pain such as what occurs in trigeminal neuralgia, since the use of carbamazepine is often limited by its adverse effects and by reduction of its analgesic effect through microsomal enzyme induction.     

Investigation of arginine A-specific cysteine proteinase gene expression profiling in clinical <Emphasis Type="Italic">Porphyromonas gingivalis</Emphasis> isolates against photokilling action of the photo-activated disinfection

Porphyromonas gingivalis is a significant root canal pathogen capable of causing endodontic infections, which during their treatment may receive sub-lethal doses of photo-activated disinfection (sPAD). As sPAD can influence microbial virulence, this study was designed to evaluate the effect of sPAD on gene expression level of arginine A-specific cysteine proteinase (rgpA), as one of the underlying virulence factors involved in the development of endodontic infection via P. gingivalis strains. To find out the sPAD against 16 clinical isolates of PAD-resistant P. gingivalis that were isolated in vivo, we used toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) as the photosensitizers, which were excited with specific wavelength of light in vitro. Quantitative real-time PCR (qRT-PCR) was then applied to monitor gene expression of rgpA in P. gingivalis isolates to characterize its virulence agent and understand the effect of sPAD on its pathogenicity. Maximal sPAD that could not decrease the count of P. gingivalis isolates were 6.25, 15.6, and 25 μg/mL at fluencies of 171.87, 15.6, and 93.75 J/cm² for TBO, ICG, and MB, respectively. ICG-sPAD could suppress the rgpA gene expression about 14-fold, while MB and TBO-mediated sPAD could cause the attenuation of rgpA expression about 4.9- and 11.6-fold, respectively. ICG-sPAD with the maximum ability to reduce rgpA gene expression compared with other photosensitizers can be an appropriate candidate for the treatment of endodontic infections.     

In vitro maturation of fresh and frozen-thawed mouse round spermatids

Both initiation and maintenance of spermatogenesis are hormonally regulated by follicle stimulating hormone (rFSH) and testosterone. Co-culture systems also have important roles in the maintenance of spermatogenic cells. In this study, the effects of FSH and testosterone, co-culture system with Vero cells and co-culture supplemented with the hormones for maturation of frozen-thawed spermatids were determined. Testicular cells were suspended from the testis of National Medical Research Institute (NMRI) male mice and divided into two parts. The first aliquot of suspension was allocated for using as fresh and the rest was quickly cryopreserved. The frozen specimens were thawed and washed using Dulbecco modified Eagle's minimum essential medium (DMEM) medium. The fresh specimens were cultured in four groups: control (cultured on DMEM with 10% FBS), hormone (cultured on a medium supplemented with rFSH and testosterone), co-culture (cultured on Vero cells) and co-culture + hormone (cultured on Vero cells combined with rFSH and testosterone). The frozen-thawed specimens were cultured accordingly. The number of spermatids was recorded daily and the survival rates of each group were evaluated using Trypan blue test. The results showed that the number of the elongating spermatids was increased during the first day of the culture of fresh hormone, co-culture and co-culture + hormone groups. Viability rates of all kinds of the spermatid reduced during the 96 h of culturing. Our findings showed that the addition of hormone could support cell viability better than the co-culture. They also confirmed that the fresh round spermatid cells can progress into elongating and elongated spermatid only within the first 2 days of the culture in hormone, co-culture and co-culture + hormone groups. In the frozen-thawed specimens no extra significant increase in the number of cells was observed.