Carina Franciscato

Antinociceptive activity of Mirabilis jalapa in mice

ETHNOPHARMACOLOGICAL RELEVANCE The infusion or decoction of Mirabilis jalapa leaves is used in traditional medicine in Brazil to treat inflammatory and painful diseases. AIM OF THE STUDY The present study examined the antinociceptive effect of Mirabilis jalapa extracts from leaves and stems in models of pain in mice. MATERIALS, METHODS AND RESULTS The crude hydroethanolic extract from leaves (CrdL) was more potent than the crude extract from stems (CrdS) to inhibit abdominal constrictions induced by acetic acid, with ID(50) values of 5.5 (2.3-13.1) and 18.0 (11.3-28.5) mg/kg, respectively. Among the fractions tested, the Eta fraction from leaves (Eta) was more effective (maximal inhibition of 83+/-8%) and potent (ID(50) of 1.1 (0.6-2.1) mg/kg) to induce antinociception. Eta and CrdL also possessed an antinociceptive effect in the tail-flick test. Pre-treatment with naloxone did not modify the antinociceptive effect of Eta, but co-administration with atropine completely prevented it. This suggests that the antinociceptive effect might depend on the cholinergic system. Instead, Eta was not able to alter the acetylcholinesterase activity in blood or spinal cord. Concerning side effects, Eta did not alter locomotor activity, body temperature, gastrointestinal transit and did not produce gastric lesions. CONCLUSION Our results demonstrate that Mirabilis jalapa presents antinociceptive activity in mice, which supports its folkloric use as an analgesic.

Delayed biochemical changes induced by mercury intoxication are prevented by zinc pre-exposure.

This work evaluated the delayed effects of mercury and the effectiveness of zinc in preventing such effects. Pups were pre-treated with 1 daily dose of ZnCl(2) (27 mg/kg/day, by subcutaneous injections) from 3rd to 7th postnatal day and received 1 daily dose of 5 mg/kg of HgCl(2), for 5 subsequent days (8-12 days old). Animals were euthanized 21 days after the end of Hg-exposure. Porphobilinogen-synthase activity as well as zinc and mercury contents was determined in the liver and kidneys. Alanine aminotransferase, aspartate aminotransferase and lactic dehydrogenase activities as well as urea, creatinine and glucose levels were analyzed in plasma or serum. Some animals were considered more sensitive to mercury, since they did not recover the body weight gain and presented an increase of renal and hepatic mercury content, urea and creatinine levels; a decrease in renal porphobilinogen-synthase and alanine aminotransferase activities, as well as a decrease in the liver and an increase in kidney weights. Some animals were considered less sensitive to mercury because they recovered the body weight and presented no biochemical alterations in spite of mercury in the tissues. Zinc prevents partially or totally the alterations caused by mercury even those that persisted for a long time after the end of exposure. These findings suggest that there is difference among the animals regarding the sensitivity to mercury.

ZnCl2 exposure protects against behavioral and acetylcholinesterase changes induced by HgCl2.

This study examined the effects of inorganic mercury exposure on behavioral and biochemical parameters and investigated the possible preventive effects of zinc on the alterations induced by mercury. Pups were exposed from 3rd to 7th postnatal day to ZnCl2 (27 mg/kg/day, s.c.) and subsequently to HgCl2 (5 doses of 5 mg/kg/day, s.c.). Each litter contained two rats for each treatment. The rats were submitted to behavioral task and litters were killed at 13 or 33 days old for acetylcholinesterase activity assays and for the determination of metal levels. Based on the results obtained from 13‐day‐old rats, they were divided in two groups of litters that were defined at the end of the experimental period (33 days) as less sensitive rats to mercury and more sensitive rats to mercury in accordance with the recovery of body weight until day 33. The mercury exposure caused accumulation of this metal in cerebrum and cerebellum in all mercury treated rats, and inhibited the cerebellum acetylcholinesterase activity from 13‐day‐old rats. Besides, the mercury‐animals of the most sensitive litters to mercury presented impairment in motor function and muscular strength verified in the beaker test, as well as a reduction of the locomotor and exploratory activities in the open field task. Zinc partially prevented all the alterations induced by mercury exposure and reduced the mercury level accumulated in cerebrum and cerebellum. This study confirms the preventive effect of zinc on behavioral alterations induced by mercury in young rats and demonstrates that the mercury behavioral effects are present even for a long time after the end of the exposure.

Cão naturalmente infectado por Trypanosoma evansi em Santa Maria, RS, Brasil

This paper describes the hematological alterations and proteinogram of a dog naturally infected by Trypanosoma evansi. This dog was presented with normochromic-normocytic anemia, leucopenia with lymphopenia followed for neutrophenia and lymphocitosis; and trombocitopenia. Hyperproteinemia with an increase of beta and gamma globulin fractions and hypoalbuminemia. By being the first case reported of T. evansi infection in dogs in Santa Maria, RS, Brazil, the epidemiological significance of such findings will alert the veterinarians to the existence of a possible parasites reservoir in the region warning to the possibility of new laboratory findings.

Trypanosoma evansi: cholinesterase activity in acutely infected Wistar rats.

The aim of this study was to evaluate cholinesterase activity during the early acute phase of Trypanosoma evansi infection in rats. Fifteen male Wistar rats were randomly distributed into three groups (n=5 animals per group): two trypanosome-infected groups (T3 and T5) and uninfected controls (C). The animals were inoculated intraperitoneally with 10(6) trypanosomes. The blood was collected by cardiac puncture on the 3rd (T3) or 5th day post-infection (T5 and C). Cerebrum and cerebellum were removed for the evaluation of acetylcholinesterase (AChE) activity. AChE activity was also evaluated in whole blood and butyrylcholinesterase activity (BUChE) in plasma samples. Parasitemia were progressive increase and parasites were observed in the peripheral blood of all infected animals one day post-inoculation. AChE activity was not altered in cerebrum and cerebellum tissues. AChE activity in blood significantly decreased in the T3 and T5 groups (26.63 and 25.86mU/lmolHb) compared with the control (37.84mU/lmolHb). In addition BUChE activity in plasma was lower in the T3 (7.01micromol BTC hydrolyzed/h/mL) than the T5 and C groups (9.84 and 12.00micromol BTC hydrolyzed/h/mL). This study therefore, shows that reductions in the activity of cholinesterase occur in acute infection by T. evansi in rats and this demonstrates an important change occurring in animals infected by the protozoan and may indicate a potential role the enzymes play in the mechanism of disease.

Antinociceptive effect of Mirabilis jalapa on acute and chronic pain models in mice.

ETHNOPHARMACOLOGICAL RELEVANCE The infusion or decoction of Mirabilis jalapa leaves is used in traditional medicine in Brazil to treat inflammatory and painful diseases. Thus, the present study was designed to investigate whether the leaf ethyl acetate (Eta) fraction from Mirabilis jalapa exhibits antinociceptive effect in clinically relevant pain models in mice. Furthermore, we have investigated the role of cholinergic system in the antinociceptive action produced by Eta in mice. MATERIALS AND METHODS The effect of Eta administered orally (10mg/kg, p.o.) in mice was verified on the painful hypersensitivity (mechanical allodynia) in models of chronic inflammation (subcutaneous injection of complete Freunds Adjuvant-CFA in the plantar surface of the right hind paw), postoperative (paw surgical incision) and neuropathic (partial sciatic nerve ligation) pain. In the chronic inflammation model, we further verified the effect of Eta treatment on paw edema and interleukin-1β (IL-1β) levels. We also investigated the role of muscarinic and nicotinic receptors in the antiallodynic action produced by Eta as well as the possible action of Eta on in vitro and ex vivo acetylcholinesterase activity in CFA treated animals. Furthermore, we verified the effect of Eta treatment on the parameters of liver and kidney lesion (level of urea, and activity of aspartate aminotransferase and alanine aminotransferase). RESULTS Eta produced marked reduction in the allodynia caused by CFA, surgical incision and partial sciatic nerve ligation. However, Eta did not alter the paw edema or the increase of IL-1β levels produced by CFA. The antinociceptive effect of Eta was reversed by the pre-treatment of animals with the antagonists of muscarinic (atropine, 5mg/kg, s.c) or nicotinic (mecamylamine, 0.001mg/kg, s.c.) receptors. Eta did not alter in vitro acetylcholinesterase activity in blood or spinal cord samples, but it reversed the increase in the acetylcholinesterase activity observed in the spinal cord samples from mice injected with CFA. Moreover, Eta did not alter the indicators of liver or kidney lesion. CONCLUSIONS Based on its use in traditional medicine, the results of the present study confirmed the antinociceptive properties of Eta in clinically relevant pain models. Also its effect on the CFA-induced chronic inflammation seems to be related to acetylcholinesterase inhibition and cholinergic system.

Lactating and nonlactating rats differ to renal toxicity induced by mercuric chloride: the preventive effect of zinc chloride.

This study evaluated the effects of HgCl2 on renal parameters in nonlactating and lactating rats and their pups, as well as the preventive role of ZnCl2. Rats received 27 mg kg−1 ZnCl2 for five consecutive days and 5 mg kg−1 HgCl2 for five subsequent days (s.c.). A decrease in δ‐aminolevulinic acid dehydratase (δ‐ALA‐D) activity in the blood and an increase in urine protein content in renal weight as well as in blood and urine Hg levels were observed in lactating and nonlactating rats from Sal―Hg and Zn―Hg groups. ZnCl2 prevented partially the δ‐ALA‐D inhibition and the proteinuria in nonlactating rats. Renal Hg levels were increased in all HgCl2 groups, and the ZnCl2 exposure potentiated this effect in lactating rats. Nonlactating rats exposed to HgCl2 exhibited an increase in plasma urea and creatinine levels, δ‐ALA‐D activity inhibition and histopathological alterations (necrosis, atrophic tubules and collagen deposition) in the kidneys. ZnCl2 exposure prevented the biochemical alterations. Hg‐exposed pups showed lower body and renal weight and an increase in the renal Hg levels. In conclusion, mercury‐induced nephrotoxicity differs considerably between lactating and nonlactating rats. Moreover, prior exposure with ZnCl2 may provide protection to individuals who get exposed to mercury occupationally or accidentally. Copyright

Mercury chloride increases hepatic alanine aminotransferase and glucose 6-phosphatase activities in newborn rats in vivo.

This work investigated the in vivo and in vitro effects of HgCl2 and ZnCl2 on metabolic enzymes from tissues of young rats to verify whether the physiological and biochemical alterations induced by mercury and prevented by zinc are related to hepatic and renal glucose metabolism. Wistar rats received (subcutaneous) saline or ZnCl2 (27 mg/kg/day) from 3 to 7 days old and saline or HgCl2 (5.0 mg/kg/day) from 8 to 12 days old. Mercury exposure increased the hepatic alanine aminotransferase (∼6‐fold) and glucose 6‐phosphatase (75%) activity; zinc pre‐exposure prevented totally and partially these mercury alterations respectively. In vitro, HgCl2 inhibited the serum (22%, 10 μM) and liver (54%, 100 μM) alanine aminotransferase, serum (53%) and liver (64%) lactate dehydrogenase (10 μM), and liver (53%) and kidney (41%) glucose 6‐phosphatase (100 μM) from 10‐ to 13‐day‐old rats. The results show that mercury induces distinct alterations in these enzymes when tested in vivo or in vitro as well as when different sources were used. The increase of both hepatic alanine aminotransferase and glucose 6‐phosphatase activity suggests that the mercury‐exposed rats have increased gluconeogenic activity in the liver. Zinc prevents the in vivo effects on metabolic changes induced by mercury.

High doses of zinc and copper alter neither cerebral metal levels nor acetylcholinesterase activity of suckling rats

This research investigated the in vivo (ZnCl2 27 mg/kg; CuSO4 10.2 mg/kg) and in vitro effects of zinc and copper on acetylcholinesterase activity of different cerebral areas, Zn and Cu levels in cerebrum, and body weight gain of young Wistar rats. Three-day-old rats were injected (s.c.) with 5 doses (saline, Zn, Cu or Zn+Cu) for 5 consecutive days and were killed 24 h after the last dose. In the other experiment, 7-day-old rats received only 1 dose (saline, Zn or Cu) and were killed at 1, 6 or 24 h after. For the in vitro experiments, the acetylcholinesterase activity from cerebrum of 8-day-old rats was analyzed in presence of Zn or Cu (0.01 to 1 mM). Regarding the in vivo experiments, only body weight gain was decreased by 5 simultaneous administrations of Zn and Cu. The acetylcholinesterase activity from cerebrum and cerebellum and cerebral zinc and copper contents were not altered by the treatments. In vitro, Cu 0.1 and 1 mM, but not Zn, inhibited the enzyme of both cerebrum and cerebellum. The enzymatic activity from cerebrum and cerebellum homogenate was more sensitive to Cu than the enzymatic activity from S2 and S1 fractions, respectively, since less metal was necessary to inhibit the enzyme.

Concentrações séricas de minerais e funções hepática e renal de frangos intoxicados com aflatoxina e tratados com montmorilonita sódica

The objective of this work was to evaluate the seric mineral concentrations and the hepatic and renal functions of broiler chicken, experimentally intoxicated with 3 ppm of aflatoxin, and submitted to different concentrations of sodic montmorillonite in the diet. In this study 720 Cobbs male broiler chickens were used, which were divided in six treatments: T1, normal diet; T2, diet with aflatoxin (3 ppm); T3, diet with sodic montmorillonite (0.25%); T4, diet with aflatoxin (3 ppm) + sodic montmorillonite (0.25%); T5, diet with sodic montmorillonite (0.50%); T6, diet with aflatoxin (3 ppm) + sodic montmorillonite (0.5%); with six repetitions of each treatment. The diet with 3 ppm of aflatoxin resulted in a significant decrease in serum concentrations of total protein, albumin, globulins and aspartate aminotransferase; there was significant decrease of seric concentration of uric acid in the diet with aflatoxin (3 ppm) + 0.25% sodic montmorillonite; in the diet with aflatoxin + 0.5% sodic montmorillonite there was significant decrease in seric concentrations of phosphorus. Aflatoxin in the diet (3 ppm) causes change in the hepatic function of broiler chickens. The use of 0.5% sodic montmorillonite is effective in preventing the toxic effects of aflatoxins, but causes decrease in phosphorus seric levels.