Topical emulsion containing pyrrolidine dithiocarbamate: effectiveness against ultraviolet B irradiation-induced injury of hairless mouse skin.

OBJECTIVES: To evaluate the effects of a topical emulsion containing pyrrolidine dithiocarbamate (PDTC) (EcPDTC) in skin oxidative stress and inflammation triggered by ultraviolet B (UVB) irradiation (dose of 4.14 J/cm2 ). METHODS: Hairless mouse received treatment with 0.5 g of EcPDTC or control emulsion (CTRLE) on the dorsal surface skin 12 h, 6 h and 5 min before and 6 h after the irradiation. Oxidative stress was evaluated by ferric reducing antioxidant power (FRAP), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS) scavenging capacity, reduced glutathione quantitation, catalase activity, superoxide anion production and lipid peroxidation products. Inflammation parameters were as follows: skin oedema, myeloperoxidase activity (neutrophil marker), matrix metalloproteinase-9 activity, collagen fibre damage, mast cell and sunburn cell counts, and cytokine production. KEY FINDINGS: Topical treatment with EcPDTC protected from UVB-induced skin injury by maintaining the antioxidant capacity levels similar to non-irradiated control group. Furthermore, EcPDTC inhibited UVB irradiation-induced superoxide anion production, lipid peroxidation and reduced skin inflammation by inhibiting skin oedema, neutrophil recruitment, metalloproteinase-9 activity, collagen fibre damage, mast cell and sunburn cell counts, and cytokine (TNF-α and IL-1ß) production. CONCLUSIONS: Topical treatment with EcPDTC improves antioxidant systems and inhibits inflammation, protecting the skin from the damaging effects of UVB irradiation.

Leishmania (L). amazonensis induces hyperalgesia in balb/c mice: Contribution of endogenous spinal cord TNFα and NFκB activation.

Cutaneous leishmaniasis (CL) is the most common form of the leishmaniasis in humans. Ulcerative painless skin lesions are predominant clinical features of CL. Wider data indicate pain accompanies human leishmaniasis, out with areas of painless ulcerative lesions per se. In rodents, Leishmania (L.) major infection induces nociceptive behaviors that correlate with peripheral cytokine levels. However, the role of the spinal cord in pain processing after Leishmania infection has not been investigated. Balb/c mice received intraplantar (i.pl.) injection of Leishmania (L). amazonensis and hyperalgesia, edema, parasitism, and spinal cord TNFα, TNFR1 and TNFR2 mRNA expression, and NFκB activation were evaluated. The effects of intrathecal (i.t.) injection of morphine, TNFα, TNFα inhibitors (etanercept and adalimumab) and NFκB inhibitor (PDTC) were investigated. The present study demonstrates that Leishmania (L.) amazonensis infection in balb/c mice induces chronic mechanical and thermal hyperalgesia in an opioid-sensitive manner. Spinal cord TNFα mRNA expression increased in a time-dependent manner, peaking between 30 and 40 days after infection. At the peak of TNFα mRNA expression (day 30), there was a concomitant increase in TNFR1 and TNFR2 mRNA expression. TNFα i.t. injection enhanced L. (L.) amazonensis-induced hyperalgesia. Corroborating a role for TNFα in L. (L.) amazonensis-induced hyperalgesia, i.t. treatment with the TNFα inhibitors, etanercept and adalimumab inhibited the hyperalgesia. L. (L.) amazonensis also induced spinal cord activation of NFκB, and PDTC (given i.t.), also inhibited L. (L.) amazonensis-induced hyperalgesia, and spinal cord TNFα, TNFR1 and TNFR2 mRNA expression. Moreover, L. (L.) amazonensis-induced spinal cord activation of NFκB was also inhibited by etanercept and adalimumab as well as PDTC i.t. TREATMENT: These results demonstrate that endogenous spinal cord TNFα and NFκB activation contribute to L. (L.) amazonensis-induced hyperalgesia in mice. Thus, spinal cord TNFα and NFκB are potential therapeutic targets for Leishmania infection-induced pain.

Pyrrolidine dithiocarbamate inhibits superoxide anion-induced pain and inflammation in the paw skin and spinal cord by targeting NF-κB and oxidative stress.

We evaluated the effect of pyrrolidine dithiocarbamate (PDTC) in superoxide anion-induced inflammatory pain. Male Swiss mice were treated with PDTC and stimulated with an intraplantar or intraperitoneal injection of potassium superoxide, a superoxide anion donor. Subcutaneous PDTC treatment attenuated mechanical hyperalgesia, thermal hyperalgesia, paw oedema and leukocyte recruitment (neutrophils and macrophages). Intraplantar injection of superoxide anion activated NF-κB and increased cytokine production (IL-1ß, TNF-α and IL-10) and oxidative stress (nitrite and lipid peroxidation levels) at the primary inflammatory foci and in the spinal cord (L4-L6). PDTC treatment inhibited superoxide anion-induced NF-κB activation, cytokine production and oxidative stress in the paw and spinal cord. Furthermore, intrathecal administration of PDTC successfully inhibited superoxide anion-induced mechanical hyperalgesia, thermal hyperalgesia and inflammatory response in peripheral foci (paw). These results suggest that peripheral stimulus with superoxide anion activates the local and spinal cord oxidative- and NF-κB-dependent inflammatory nociceptive mechanisms. PDTC targets these events, therefore, inhibiting superoxide anion-induced inflammatory pain in mice.

In vitro and in vivo trypanocidal activity of H2bdtc-loaded solid lipid nanoparticles.

The parasite Trypanosoma cruzi causes Chagas disease, which remains a serious public health concern and continues to victimize thousands of people, primarily in the poorest regions of Latin America. In the search for new therapeutic drugs against T. cruzi, here we have evaluated both the in vitro and the in vivo activity of 5-hydroxy-3-methyl-5-phenyl-pyrazoline-1-(S-benzyl dithiocarbazate) (H2bdtc) as a free compound or encapsulated into solid lipid nanoparticles (SLN); we compared the results with those achieved by using the currently employed drug, benznidazole. H2bdtc encapsulated into solid lipid nanoparticles (a) effectively reduced parasitemia in mice at concentrations 100 times lower than that normally employed for benznidazole (clinically applied at a concentration of 400 µmol kg(-1) day(-1)); (b) diminished inflammation and lesions of the liver and heart; and (c) resulted in 100% survival of mice infected with T. cruzi. Therefore, H2bdtc is a potent trypanocidal agent.

Dietary risk assessment of organophosphorus and dithiocarbamate pesticides in a total diet study at a Brazilian university restaurant.

In this study ready-to-eat food samples were collected in the production line of the university restaurant of the University of Brasilia, Brazil, which serves non-vegetarian and vegetarian meals daily. Samples were analysed for the presence of ten organophosphorus insecticides (OPs) by GC/FPD, after extraction with ethyl acetate and anhydrous sodium sulfate (LOQ = 0.002 mg kg(-1)), and for dithiocarbamate fungicides, as CS(2), using the spectrophotometric method (LOQ = 0.05 mg kg(-1)). About 43% of the 175 samples analysed contained at least one OP compound at levels up to 1.83 mg kg(-1). Methamidophos was the compound most detected (37.7%), present in most of the soup, soybean and salad samples. No OP residues were found in fruit juice, beans and bran rice samples. The cumulative acute intake of OPs was estimated using methamidophos and acephate as index compounds (IC). The total cumulative intake represented 9.1% and 47.7% of the methamidophos ARfD for the non-vegetarian and vegetarian diets, respectively. When acephate was used as IC, the total intakes represented 20.7% and 116% of the ARfD for the non-vegetarian and vegetarian diets, respectively. Dithiocarbamates were detected in 70% of the 177 samples analysed, at levels up to 0.51 mg kg(-1) CS(2); all salad samples were positive and no residues were found in fruit juice. The chronic intake of dithiocarbamates represented 8.6 and 8.9% of the ADI (mancozeb) for the vegetarian and non vegetarian diets, respectively.

Synergistic antiinflammatory effect of NF-kappaB inhibitors and steroidal or non steroidal antiinflammatory drugs in the pleural inflammation induced by carrageenan in mice.

OBJECTIVES: Experiments were designed to determine whether or not inhibitors of NF-Kappa B (NF-kappaB) exhibit antiinflammatory effects when assessed in carrageenan-induced pleural inflammation in the mouse. MATERIAL AND METHODS: Adult mice of both sexes received pyrrolidine dithiocarbamate (PDTC) or sulfasalazine administered intraperitoneal by at several time points before intrapleural injection of carrageenan (1%) and the exudation and the total and differential cells were analysed. RESULTS: PDTC or sulfasalazine largely and almost completely inhibited the leukocyte infiltration and the exudation induced by intrapleural administration of carrageenan, when assessed 4 h (but not 48 h) after carrageenan injection. The combination of subliminal doses of PDTC or sulfasalazine with steroidal (dexamethasone) or non-steroidal (indomethacin, meloxicam, nabumetone, diacerein) antiinflammatory drugs, which alone had no antinflammatory action, greatly inhibited both the pleural cell infiltration and exudation induced by carrageenan. The highest inhibition of leukocyte infiltration was observed with the combination of PDTC or sulfasalazine with dexamethesone (84 and 75%, respectively). CONCLUSIONS: These results indicate that nuclear factor-kappaB might play an important role in the modulation of the early phase of the pleural inflammatory response induced by carrageenan in the mouse. Furthermore, our results demonstrate for the first time a marked synergistic interaction among dexamethasone--and to a lesser extent among nonsteroidal antiinflammatory drugs--and the NF-kappaB inhibitors, suggesting that this association may be of potential interest for the management of certain inflammatory processes, including asthma therapy.

Combination and individual antitumor effects of hyperthermia, cisplatin, and selected dithiocarbamates.

The antitumor effects produced by combinations of cisplatin (Pt), substituted dithiocarbamates (dimethyldithiocarbamate [DmDTC] and sodium N-methyl-D-glucamine dithiocarbamate [NMGDTC]) and hyperthermia (H) were measured and compared to those produced by single agents alone in C3H/HeN mice bearing the transplantable radiation-induced fibrosarcoma, RIF-1, in one or both hind feet. The average tumor volumes of control and treatment groups were compared periodically after treatment with H. Combinations of H and Pt completely resolved established foot tumors in 10/13 mice. However, evidence of long-term nephrotoxicity and gastrointestinal (GI) toxicity became evident causing death of these mice within 120 to 122 days after tumor inoculation. Hyperthermia plus DmDTC resolved tumors in heated and non-heated feet in 3/8 mice, thus demonstrating both ipsilateral and contralateral anti-tumor activity. Furthermore, H-Pt-NMGDTC produced complete tumor resolution in 7/13 mice; these mice survived and were tumor-free 180 days post inoculation and autopsies revealed no appreciable nephro- or GI toxicity. In addition, 4/8 mice underwent complete tumor resolution in heated left feet plus dramatic retarding of tumor growth in unheated right feet (ipsilateral and contralateral anti-tumor effects). Five heat-treated left foot tumors resolved in the H-Pt-DmDTC group with one mouse demonstrating resolution of tumor in both feet. Advanced foot tumors were treated with H-DmDTC and H-Pt-DmDTC. Hyperthermia and Pt were administered on day 0 of the experiment and DmDTC on days 0 through 3; dramatic tumor shrinkage continued through day 6 for a total of 75 to 80 percent reduction of tumor volume in both groups. The concurrent administration of DmDTC or NMGDTC with H and Pt prevented or greatly reduced nephrotoxicity and GI toxicity in all experiments without retarding anti-tumor efficacy.