The Fraction of the Snake Venom, Its Leishmanicidal Effect, and the Stimulation of an Anti-Leishmania Response in Infected Macrophages

BACKGROUND AND AIMS

Due to the lack of an effective vaccine and complexity of the control measures against vectors and reservoir hosts, the control of leishmaniasis depends primarily on chemotherapy. This study was aimed to assess the snake venom, Naja naja oxiana fraction 11(NNOVF11) on Leishmania infantum and its broad mode of action.

METHODS

A wide range of in vitro advanced assays including high-performance liquid chromatography (HPLC), MTT (3-[4, 5-Dimethylthiazol-2-yl]-2, 5diphenyltetrazolium bromide; Thiazolyl blue), macrophage assays, quantitative real-time polymerase chain reaction (qPCR), flow cytometry and enzyme- linked immunosorbent assay (ELISA) on L. infantum promastigote and amastigote stages were used. IC₅₀ values of L. infantum stages, CC₅₀ value, and apoptosis were also analyzed.

RESULTS

The NNOV-F11 demonstrated strong antileishmanial activity against L. infantum stages in a dose-dependent manner compared to the untreated control group. Interleukin (IL)-12, TNF-α, and iNOS genes expression as the indicators of T helper(h)1 response significantly increased; in contrast, the expression level of IL-10, as the representative of Th2 response significantly decreased (p < 0.001). Reactive oxygen species (ROS) detection showed a significant increase (p < 0.001) after treatment with different concentrations of NNOV-F11, unlike arginase (ARG) activity, which displayed a significant reduction (p < 0.001).

CONCLUSION

NNOV-F11 possessed a potent inhibitory effect on L. infantum stages with the multifunctional and broad mode of actions, which promoted the immunomodulatory role, induced ROS production, stimulated apoptotic-like mechanisms, and inhibited L-ARG activity, which collectively led to the parasite death. Further studies are crucial to assess the effect of the NNOV-F11 on animal models or clinical settings.

Dirofilariosis caused by Dirofilaria immitis in the south of Kerman province, Iran

BACKGROUND

Dirofilariosis due to Dirofilaria immitis is endemic in various areas of Iran. Domestic dogs are the main reservoirs and represent a major potential infection source for the vector and humans.

OBJECTIVE

This study aimed to explore the prevalence of dirofilariosis due to D.immitis and its public health importance in domestic dogs in the Jiroft district, south of Kerman province, Iran, by serological and parasitological methods.

METHODS

This descriptive study was carried out as a cross-sectional investigation. A questionnaire was completed for 100 domestic dogs from May 2017 to February 2018 and recorded their age, sex, and clinical features. Also, we used enzyme-linked immunosorbent assay (ELISA) to identify antigens of heartworms in the bloodstream, with 98% sensitivity and 100% specificity, and parasitological techniques (Knott's test) to detect microfilariae in canine blood in Jiroft district, south of Kerman province, Iran.

RESULTS

Overall, 10 (10%) and 4 (4%) domestic dogs were infected as confirmed by ELISA and modified Knott's tests, respectively. The rate of occult infections in the ELISA test than Knott's test was 60%. No significant difference was found between dirofilariosis and gender. In contrast, there was a significant difference between dirofilariosis infection and age (P < 0.05).

CONCLUSION

The present findings could help understand the epidemiological aspects of D. immitis for future control programs and take appropriate preventive and therapeutic strategies against the disease.

Evaluation of Glutathione Bioactivity on Toxoplasma Gondii in BALB/c Mice Post Impact of Selenium and Calcium Supplementation

BACKGROUND

Studies have shown that selenium is an essential component of glutathione as an important antioxidant to reduce oxidative stress and inhibit intracellular parasites' growth. In contrast, calcium in the cytosol of such parasites plays a key role in the entry of the parasite into the host cell and its primary motility.

AIMS AND OBJECTIVES

The present study was designed to evaluate and compare glutathione peroxidase bioactivity effects post administration of selenium and calcium in BALB/c mice infected by Toxoplasma gondii.

METHODS

Sixty BALB/c mice susceptible to T. gondii were randomly divided into twelve groups of case and control groups. There were six control groups including two positive controls infected only with the parasites either 10⁴ or 5×10⁴, non-infected and untreated groups. Treated controls received only calcium, selenium, or both respectively. Case groups were infected with 10⁴ or 5×10⁴ parasites. While each set of three case groups separately received minerals alone or together. Mice were orally fed with 200 μg selenium, 50 μg calcium or their combination for 7 days. Mice were infected by parasite's tachyzoites. Sera of mice were kept and the peritoneal macrophages were isolated for counting tachyzoites during infection.

RESULTS

The results showed that selenium unlike calcium was significantly effective in reducing Toxoplasma tachyzoites compared to control groups. Moreover, glutathione peroxidase [GPX] activity was elevated in mice treated with selenium and vice versa decreased in mice treated with calcium.

CONCLUSION

Administration of selenium unlike calcium reduced Toxoplasma tachyzoites proliferation by elevating bioactivity of selenium-dependent detoxification enzyme, GPX.