Mg Of Carrageenan Research Articles

Development of a Vaginal Fast-Dissolving Insert Combining Griffithsin and Carrageenan for Potential Use Against Sexually Transmitted Infections

Precoital, on-demand topical microbicides to reduce a woman's risk of sexually transmitted infections have been in development for nearly 3 decades, but no product has been approved due to acceptability issues and poor adherence in clinical trials. We set out to develop a self-administered vaginal fast-dissolving insert (FDI) produced by freeze-drying that would deliver safe and effective amounts of the antiviral agents griffithsin (GRFT) and carrageenan (CG) and would have properties women and their partners find acceptable. We evaluated FDI physical criteria, attributes of the gel produced upon dissolving, and GRFT stability. The lead formulation, FDI-024, was selected from 13 candidates and contains 4 mg of GRFT, 15 mg of CG, and excipients (the cryoprotectant sucrose and bulking agents dextran 40 and mannitol). The FDI exhibits good friability and hardness and is stable for at least 6 months at up to 40°C/75% relative humidity. It disintegrates in less than 60 s in a physiologically relevant volume (∼1 mL) of simulated vaginal fluid, forming a viscous semi-solid gel with favorable mucoadhesive and spreading properties. The formulation retains the antiviral activity of GRFT and CG against HIV type 1 and human papillomavirus, respectively, in cell-based assays.

Assessment of immune response in periparturient dairy cows using ex vivo whole blood stimulation assay with lipopolysaccharides and carrageenan skin test

The transition period is known to be the most critical phase in the life of high yielding dairy cow. Changes in the immune functions have been observed during the transition period which may account for the onset of clinical and subclinical (e.g. inflammatory response) problems at calving or at the beginning of lactation however this relationship has not yet been adequately investigated. Thus, to establish the potential of the periparturient dairy cow's immune system to respond to stimuli, two challenges [an ex vivo whole blood stimulation assay (WBA) with lipopolysaccharides and a carrageenan skin test (CST)] were performed in addition to characterizing the metabolic and inflammatory profile. The WBA was performed using 0, 0.01 and 5μg LPS/mL on whole blood and CST was administered by subcutaneous injection of 0.7mL solution containing 4.2mg of carrageenan to the shoulder region of the cows. These tests were performed on 10 Holstein-Friesian cows at −45±2, −20±2, −3, 3, 7, 28±2 days from parturition (DFP). Cows were also monitored for health status, body condition score, milk yield. The results demonstrate a higher production of IL-1β and IL-6 from leukocytes after LPS stimulation around calving (from −3 to 3 DFP) compared to −45 DFP (P<0.05). Moreover, IL-6 (but not IL-1β) was able to reach close to the maximum response at the lower stimulus intensity (0.01μg LPS/mL), maintaining a higher response over a longer time in early lactation. The release of higher levels of IL-6 in the transition period, with low LPS dose, suggests its crucial role in the regulation of inflammatory response around calving. The response of cows to CST decreased a few days before calving (−3 DFP) compared with response at −45 and 28 DFP (P<0.05), and remained low in the first week of lactation. This result suggests the reduction of the functionality of some vascular factors, which decreases diapedesis. Overall, the WBA and CST tests confirm changes in immunocompetence around calving. These tests are able to better describe the changes of the innate immune response at a local and systemic level, mainly when combined with conventional metabolic and inflammatory indices.

A comparative study on the anti-inflammatory effects of single oral doses of naproxen and its hydrogen sulfide (H2S)-releasing derivative ATB-346 in rats with carrageenan-induced synovitis

BackgroundNon-steroidal antiinflammatory drugs (NSAIDs) are the most commonly prescribed agents for arthritic patients, although gastric effects limit their long-term use. Considering the reported gastric safety of hydrogen sulfide (H2S)-releasing NSAIDs, in addition to the anti-inflammatory effects of H2S administration to rats with synovitis, we decided to evaluate the effects of the H2S-releasing naproxen derivative ATB-346 in this animal model.MethodsMale Wistar rats were anesthetized with inhalatory halothane and pre-treated with equimolar oral doses of either naproxen (0.3, 1, 3 or 10 mg/kg) or ATB-346 (0.48, 1.6, 4.8, or 16 mg/kg) 30 min before the i.art. injection of 7.5 mg of carrageenan (CGN) into the right knee joint cavity. Joint swelling and pain score were assessed after 1, 3 and 5 h, and tactile allodynia after 2 and 4 h. After the last measurement, the joint cavity lavages were performed for counting of the recruited leukocytes. The drugs (at the highest doses) were also tested for their gastric effects by evaluating macroscopical damage score and neutrophil recruitment (measured as myeloperoxidase – MPO activity) in the stomachs 5 h after administration of the drugs. In addition, the serum naproxen pharmacokinetic profiles of both compounds, administered at the highest equimolar doses, were obtained during the first 6 h after dosing.ResultsAt the two highest tested doses, both naproxen and ATB-346 reduced edema and pain score (measured 3 and 5 h after CGN; P < 0.001). Tactile allodynia was similarly inhibited by ~45% 4 h after CGN by both naproxen (at 1, 3 and 10 mg/kg) and ATB-346 (at 1.6 and 4.8 mg/kg; P < 0.001), as well as leukocyte infiltration. Naproxen (but not ATB-346) induced significant gastric damage and, despite the increased gastric MPO activity by ~130% in the naproxen-, but not in the ATB-346-treated rats, this effect was of no statistical significance.ConclusionThe presence of a H2S-releasing moiety in the ATB-346 structure does not impair the antiinflammatory activity of the parent compound in rats with CGN-induced synovitis. In addition, released H2S may account for the absence of deleterious gastric effects, thus making of ATB-346 a potentially useful therapeutic alternative to traditional naproxen for treatment of patients with arthritis.

Environmental housing affects the duration of mechanical allodynia and the spinal astroglial activation in a rat model of chronic inflammatory pain

In this study, we aimed at investigating the effect of an enriched environment (EE) on the recovery from chronic inflammatory pain. Inflammatory pain was induced by the injection of 2 mg of carrageenan (CAR) into the right knee of male Sprague–Dawley rats ( n = 34). Rats were housed either singly (S-housed) or in an EE (EE-housed). The EE consisted of a large cage ( L × W × H = 2.0 × 1.0 × 0.8 m) containing various attributes (e.g. running wheels, shelter house, climbing frame). Withdrawal response to von Frey filament was used to assess mechanical allodynia at days post-operative (DPO) − 1, 1, 7, 14, 21 and 28. S-housed animals showed a marked tactile sensitivity in the ipsilateral paw from DPO1 to DPO21. Four weeks after the CAR injection, S-housed rats were no longer allodynic. In contrast, EE-housed rats showed a significantly faster recovery: already at DPO21, they were no longer allodynic. In a first attempt to analyse the possible role of astroglial cells in the EE-induced effect, histological analysis at DPO21 was performed. Immunohistochemical staining of the spinal dorsal horn at L3–L5 indeed showed that spinal levels of astroglial activation are different between the two housing groups and therefore may play a role in the EE-induced effect on the duration of mechanical allodynia. In conclusion, our results showed that EE-housing results in a reduced duration of mechanical allodynia in chronic inflammatory pain in rats. Astroglial activation is suggested to be involved in this housing effect.

Peripheral nitric oxide in carrageenan-induced inflammation

Recent studies have suggested that nitric oxide (NO) peripherally produced by different nitric oxide synthase (NOS) isoforms contributes to edema formation and development of hyperalgesia. The present study was designed to examine the effects of NOS isoforms on NO release in carrageenan-induced inflammation at various time points. A microdialysis probe was implanted subcutaneously into the glabrous skin of hindpaws of Sprague–Dawley rats under pentobarbital anesthesia. After sample collection to obtain the basal level of the total amount of nitrite and nitrate (NO 2 −/NO 3 −), modified Ringer solution, a non-selective NOS inhibitor, NG monomethyl- l-arginine acetate ( l-NMMA), or an iNOS inhibitor, aminoguanidine hemisulfate (AG) was perfused through the microdialysis probe. 2 mg of carrageenan was injected into the plantar surface of the probe-implanted hindpaw. Carrageenan was also injected in rats that had undergone sciatic nerve sectioning. Carrageenan significantly increased the dialysate concentrations of NO 2 −/NO 3 − for more than 8 h. l-NMMA suppressed the carrageenan-induced increase in NO 2 −/NO 3 − concentration. Although AG did not suppress the increase in NO 2 −/NO 3 − for the first 2 h after carrageenan injection, significant suppression of the increase in NO 2 −/NO 3 − was observed from 2.5 h after carrageenan injection. In the rats in which the sciatic nerves had been denervated, the increases in concentrations of NO 2 −/NO 3 − were completely suppressed up to 3 h and partially suppressed 4.5–8 h after carrageenan injection. The results of the current study show that carrageenan induces peripheral release of NO, the production of which is mediated by nNOS in the early phase and by both nNOS and iNOS in the late phase of carrageenan-induced inflammation.

Role of nitric oxide during carrageenan-sensitized endotoxin shock in mice

We have previously clarified that sensitization with a sulfated polygalactose, carrageenan (CAR), enhances endotoxin-induced tumor necrosis factor (TNF) production and lethality in mice. The present study was performed to examine the role of nitric oxide (NO) in CAR-sensitized septic mice with two different types of NO synthase (NOS) inhibitors, a non-selective inhibitor to NOS subtypes, N ω-nitro-L-arginine methyl ester (L-NAME), and a selective inhibitor to inducible NOS, aminoguanidine. Seven or eight-week-old male ddY mice were given 5 mg of CAR intraperitoneally as a primer. Then, 5 μg of lipopolysaccharide (LPS) was injected into the tail vein 16 hours later the pretreatment. Marked synthesis of NO was induced in CAR-sensitized mice, as indicated by the high plasma levels of the stable endproducts, NO 2 − NO 3 − peaking at 12 hr after the LPS challenge. The peak values at 12 hr after the LPS challenge were dependent on the dose of CAR with 1 to 5 mg, although the injection with 10 mg of CAR was adversely inhibited NO production compared with 5 mg of CAR. The LPS challenge was followed by either L-NAME (0.25, 0.5 or l mg) or aminoguanidine (1, 2 or 4 mg) in the septic mice sensitized with 5 mg of CAR. L-NAME reduced the plasma NO 2 − NO − level in a dose-dependent fashion, although it augmented liver injury, as measured by plasma levels of ornithine carbamyltransferase (OCT) and the LPS-induced lethality in a dose-dependent fashion. In contrast, aminoguanidine did not significantly deteriorate either liver injury or lethality in spite of the decrease of NO endproducts in a similar fashion to L-NAME. These findings suggest that the inhibition of constitutive NOS is detrimental and augments LPS-induced liver injury and subsequent lethality.

Pathogenicity test for Listeria monocytogenes using immunocompromised mice.

The lethality of Listeria isolates was determined with normal adult mice and mice that were immunocompromised by treatment with 20 mg of carrageenan per kg. The mean 50% lethal doses (LD50s) of the pathogenic isolates were significantly lower (alpha = 0.05) in the immunocompromised mice than in the untreated mice, with an average reduction of 5.8 log10 units. In contrast, the mean LD50s of the nonpathogenic isolates were lower in the immunocompromised mice by an average of only 0.4 log10 unit, a difference that was not significant (alpha = 0.05). When immunocompromised mice were used, the LD50s of pathogenic Listeria monocytogenes isolates were lower than those of nonpathogenic L. innocua and L. seeligeri isolates by greater than or equal to 6 log10 units and lower than those of nonpathogenic L. ivanovii isolates by greater than or equal to 4 log10 units. Pathogenic L. monocytogenes isolates could be distinguished from nonpathogenic isolates by their ability to cause deaths in immunocompromised mice in 3 days at a dose of approximately 10(4) CFU per mouse. An alternative procedure using iron-overloaded mice failed to effectively differentiate pathogenic Listeria isolates.

Inhibition of carrageenan edema formation by organotin compounds

The effects of a single p.o. dose of 0.3-10 mg/kg of organotin compounds such as dibutyltin dichloride (Bu2SnCl2) and triphenyltin chloride (Ph3SnCl) on the development of edema after subplantar injection of 0.5 mg of carrageenan in 0.05 ml of pyrogen-free saline were examined as compared with those of hydrocortisone. Bu2SnCl2, Ph3SnCl and hydrocortisone did not significantly inhibit the development of the first phase of edema at any dose level, but produced more than 90, 70 and 90% inhibition of the second phase, respectively, at a dose of 10 mg/kg 1 hr before the irritant. Moreover, these inhibitions of the second phase were dose-dependent.

Carrageenan stimulates the release of dialyzable helper factors

We found that 1 mg of carrageenan (CGN) could enhance the primary antibody response of BALB/c spleen cells to sheep erythrocytes (SRBC). This enhancement was dependent on the strain of mouse injected as well as the type of CGN administered. In vitro experiments with spleen cells from mice treated with CGN in vivo showed that these cells release low molecular weight factor(s) which enhanced the in vitro antibody response to SRBC. Thy 1 − cells were clearly involved in the production of this factor since depletion of these cells eliminated the helper effect of CGN-treated spleen cells. Our results suggest one possible mechanism by which CGN can modulate the immune response.

Ortho-Tolidine and Sodium Hypochlorite for the Determination of Carrageenan and Other Ester Sulfates

Carrageenan and other sulfated polysaccharides react with o-tolidine and sodium hypochlorite in a buffered medium to produce a purple or purplish-green color with maximum absorption at 545 to 550nm, pH 1.4; 550 ran, pH 2.0; 565 to 570nm, pH 2.5; and 590 to 595nm, pH 3.0. Proteins, carboxylic, phos-phorylated and neutral polysaccharides do not react between pH 1.4 to 3.0. Color density varies with the degree of sulfation of the polysaccharides. Recoveries of up to 86% were obtained for carrageenan added to milk and to other dairy products. The standard deviation ranged from±.49 to±.51mg of carrageenan when 10mg of the hydrocolloid were added. The method will detect .025% of carrageenan.