Therapeutic potential of certain drug combinations on paclitaxel-induced peripheral neuropathy in rats.

BACKGROUND AND AIMS: Experimental research and clinical data support the potential combination therapy for the treatment of neuropathic pain. We aimed to investigate the analgesic effect of the following associations: gabapentin + etifoxine; tramadol + etifoxine; gabapentin + tramadol, in an experimental model of peripheral neuropathy induced by paclitaxel. MATERIALS AND METHODS: Neuropathy was induced in male Wistar rats by the daily administration of 2 mg÷kg body weight (bw) paclitaxel intraperitoneally, four days in a row. Analgesics were given concomitantly with paclitaxel, in the following doses: tramadol 15 mg÷kg bw, etifoxine 100 mg÷kg bw, gabapentin 300 mg÷kg bw. Tactile allodynia and mechanical hyperalgesia were assessed using the Dynamic Plantar Aesthesiometer apparatus (Ugo Basile). After 18 days of treatment, the brain and liver tissue susceptibility to lipid peroxidation was evaluated and the sciatic nerve histological examination of the effect on myelin fibers was performed. RESULTS AND CONCLUSIONS: Experimental data have shown a strong analgesic effect of these three tested combinations expressed mainly by the statistically significant increased maximum response time, both in the assessment of allodynia and hyperalgesia. The gabapentin + tramadol combination lead to the maximum analgesic effect, immediately after the discontinuation of paclitaxel (44.94%, p<0.0001) and throughout the study. The treatment associated with tramadol caused a reduction in lipid peroxidation in the brain as compared to paclitaxel group. Combination therapy showed reduced damage to myelinated fiber density in the sciatic nerve. The drug combinations used in the experiment showed therapeutic potential in the fight against neuropathic pain induced by the administration of taxanes.

Comparing the antifibrotic effect on the liver of Telmisartan and Pentoxifylline, in a Wistar rat experimental model.

Chronic liver diseases are characterized by higher or lower changes of the liver lobe architecture (parenchymatous and vacuolar), the accumulation of inflammatory and collagen infiltrates, mainly in the Kiernan spaces and a progressive evolution to liver cirrhosis. Despite the progresses made in knowing the mechanisms of liver fibrosis and the development of some antiviral drugs with a high potential, that can induce fibrosis regression, there still continues to exist the need for a specific antifibrotic treatment. In our study, we used four groups of Wistar rats: a reference group and three groups that received 40% carbon tetrachloride (CCl4), intraperitoneally, twice a week, for four weeks; after one week since starting the administration of CCl4, one of the three groups received, through oral gavage, Telmisartan (TS) 8 mg÷kg, and another received Pentoxifylline (PTX) 20 mg÷kg, dissolved in saline solution, for four weeks. The antifibrotic action of the two drugs was analyzed by evaluating the histopathological and immunohistochemical changes of hepatocytes, hepatic stellate cells (Ito cells) and macrophages (Kupffer cells). The study highlighted that in the group treated with TS, the process of fibrillogenesis was significantly reduced, in comparison to the group treated with PTX and with the reference group.

Pharmacotoxicological screening on new derivatives of beta-phenylethylamine, potential agonists of beta3-adrenergic receptors.

BACKGROUND AND AIMS: Beta3-adrenergic receptors (beta3-ARs) have been initially characterized in 1989. Afterwards, their tissue distribution was established: white and brown adipose tissue, central nervous system, myocardium (atrial and ventricular), blood vessels, smooth gastrointestinal muscles (stomach, small intestine, colon), gallbladder, urinary bladder, prostate, skeletal muscles. Non-clinical trials have demonstrated the major implication of beta3-ARs in glucose metabolism, implicitly, in insulin release, and also in obesity. Therefore, new compounds were synthesized starting from beta-phenylethylamine nucleus and substituted in various positions, for possible antidiabetic and÷or antiobesity action. MATERIALS AND METHODS: In the present research, the antidiabetic action of newly synthesized compounds was investigated on an experimental model of alloxan-induced diabetes, administered in dose of 130 mg÷kg body weight (bw), intraperitoneally (i.p.). After 14 days of treatment, glycemia and enzymes involved in homeostasis of glucose metabolism, glucose-6-phosphate dehydrogenase (G6PD), glucose-6-phosphatase (G6Pase) and hexokinase were determined. Animals were then euthanized and histopathology examinations were performed on harvested liver, kidney, spleen and brain in order to document pathological changes induced by alloxan-induced diabetes and÷or by tested compounds. RESULTS AND CONCLUSIONS: Glycemia in animals treated with the tested compounds decreased statistically significant for groups C2 and C3 (-42.13% and -37.2%, respectively), compared to diabetic control group. C2 was also the compound to favorably modify the dynamics of determined enzymes, together with the display of very good safety profile supported by minor, non-significant, histopathological changes.

Oral toxicity study of certain plant extracts containing pyrrolizidine alkaloids.

Pyrrolizidine alkaloids (PAs) are a class of toxic compounds which are found in plants. Poisoning caused by these toxins is associated with acute and chronic liver damage. Tussilago farfara (coltsfoot), Petasites hybridus (common butterbur), Senecio vernalis (eastern groundsel) and Symphytum officinale (comfrey) are traditional phytotherapic species, which beside the therapeutic bioactive compounds contain PAs. The aim of the paper was to assess the safety of some dry extracts obtained from these species. For the determination of acute toxicity, Organization for Economic Cooperation and Development (OECD) Guideline No. 423 was used. For the determination of repeated dose oral toxicity, Senecionis vernalis herba and Symphyti radix extracts (250 mg÷kg) were administrated, by gavage, for 28 days, and their effects on animal weight, liver and biliary functions, hepatic tissue and oxidative stress were investigated. After the acute toxicity testing, the dry extracts were placed in the GHS Category V (LD50>5000 mg÷kg, p.o.). For the subacute toxicity testing, no death or any signs of toxicity were observed. Also, no significant differences in biochemical parameters were observed between control and treated groups. The observed histopathological lesions were non-specific and were not consistent with the data reported in the literature for PAs exposure. In conclusion, the administration for 28 days, of the tested extracts, in a dose which correspond to a PAs concentration over the limits imposed in some countries, produced no hepatic and biliary toxic effects. Further studies, extended over a longer period of time, are needed in order to determine the safety of plant extracts containing PAs.

Influence of hyperforin on the morphology of internal organs and biochemical parameters, in experimental model in mice.

BACKGROUND AND AIMS: Hyperforin (HY) is used to treat depression and skin irritation and has been shown a number of pharmacological activities. The literature does no cite data on changes that may occur in the body after HY intake (ethylene diammonium salt - EDS) in long-term administration. From this point of view, the present work is a key to determining the pharmacotoxicological profile of the HY-EDS, in long-term administration. MATERIALS AND METHODS: In present research, the influence of toxic doses of HY-EDS was investigated on the biochemical serum parameters and the histopathological changes in internal organs on the experimental mice model. For acute toxicity determination, the HY-EDS was tested in doses of 2000-5000 mg÷kg, administered once per day orally. For subacute toxicity, the HY-EDS was tested in three groups of mice, in doses of 50, 75 and 100 mg÷kg÷day, administered once daily, for 28 consecutive days. RESULTS AND CONCLUSIONS: As concern acute toxicity, a lethal effect has not occurred at any of the two tested doses and HY-EDS was classified as Class V toxic: median lethal dose (LD50) >5000 mg÷kg, p.o. After 14 days of follow-up in acute toxicity, the experimental results showed a statistically significant increase of aspartate transaminase (AST) and alanine transaminase (ALT), compared to the control group. There were no changes in creatinine and serum glucose compared to the control group. After the administration of repeated doses, it was observed an increase of serum transaminases and alkaline phosphatase. Histological examination revealed that the liver injuries were in an initial stage, making them reversible in case of HY-EDS treatment discontinuation. There was no evidence of kidney damage to any of the doses of HY-EDS.

Antifibrotic action of telmisartan in experimental carbon tetrachloride-induced liver fibrosis in Wistar rats.

BACKGROUND AND AIMS: Liver fibrosis is the increasingly accumulation of extracellular matrix (ECM), caused by chronic liver injuries, and represents a difficult clinical challenge in the entire world. Currently, the advanced knowledge of the cellular and molecular mechanisms of liver fibrosis showed that collagen-producing cells, like activated hepatic stellate cells (HSCs), portal fibroblasts and myofibroblasts are activated by fibrogenic cytokines, such as angiotensin II, transforming growth factor-beta 1 (TGF-ß1), and leptin. Because of these, we tested telmisartan, an angiotensin II (AT1) receptor blocker and a peroxisome proliferator-activated receptor-γ (PPARγ) partial agonist, for investigate its antifibrotic action, on experimental model of carbon tetrachloride-induced liver fibrosis. MATERIALS AND METHODS: In this research, we used two groups of Wistar rats, which received intraperitoneal (i.p.) injection of carbon tetrachloride (CCl4) 40% dissolved in olive oil, twice weekly for four consecutive weeks (initial dose of 5 mL÷kg, and other doses 3 mL÷kg). After one week, one group was received by gavage telmisartan (TS) dissolved in saline 0.9%, daily in dose of 8 mg÷kg, for 28 days. One group of Wistar rats was used for control. The antifibrotic action of telmisartan was investigated on the pathological changes of the liver and immunohistochemical analysis for hepatic stellate (Ito) cells (HSCs) reaction using anti-alpha-smooth muscle actin (anti α-SMA) antibody and macrophages cells (Kupffer cells) reaction using anti-CD68 antibody. RESULTS AND CONCLUSIONS: In group treated with telmisartan, hepatic fibrogenesis process was significantly reduced, in comparison with CCl4 group.

Effect of Scutellariae herba extracts in experimental model of skin burns: histological and immunohistochemical assessment.

The skin burns are an issue of great interest and seriousness in the public health domain, by their destructive features. Natural medicinal products are extensively used from ancient times, in ethnopharmacology, for the treatment of skin injuries (burns, wounds, ulcerations) due to the local modulation of the cellular response, in terms of emollient, demulcent, astringent, anti-inflammatory, antimicrobial, epithelizing, wound-healing, immunomodulatory and antioxidant effects. AIM: Histological and immunohistochemical assessment of antiseptic, anti-inflammatory, astringent and cicatrizing effects of Scutellariae (altissimae, galericulatae, hastifoliae) herba extracts administered in the form of 20% topical preparations (cold-creams), in experimental model of third degree skin burns, at Wistar rats. Caffeic acid and chlorogenic acid derivatives were identified in all herbal samples. The most active was the cold-cream with 20% Scutellariae hastifoliae herba soft extract, promoting the neoangiogenesis vessels and granulation tissue. Flavonoids, tannins and polyphenol carboxylic acids are the main active principles responsible for antiseptic, anti-inflammatory, astringent and cicatrizing effects of herbal extracts. Beeswax, from the formulation of cold-creams, acts as emollient, epithelizing, cicatrizing and biostimulator.