Parámetros hematológicos y de estrés oxidativo en pingüinos de Magallanes rehabilitados por contaminación con petróleo / Blood and oxidative stress parameters of oil-spill rehabilitated magallanic penguins

Los pingüinos de Magallanes son entre las aves marinas, la especie más afectada por la contaminación con petróleo en Chubut y Santa Cruz. Una de las consecuencias adversas de la exposición a hidrocarburos y otros contaminantes es el aumento de los niveles celulares de especies reactivas del oxígeno o estrés oxidativo, considerados herramientas útiles como biomarcadores del impacto de la exposición a contaminantes químicos peligrosos. El objetivo de este trabajo fue evaluar parámetros hematológicos y marcadores de estrés oxidativo durante la rehabilitación de tres pingüinos empetrolados provenientes del Área Natural Protegida Punta Tombo, Chubut, Argentina. Se tomaron tres muestras de sangre por individuo: la primera muestra al arribo de los pingüinos al centro de rehabilitación, la segunda una semana después y una última muestra antes de ser liberados. Se obtuvieron la cantidad total de leucocitos, la razón heterófilos/linfocitos, el hematocrito y las concentraciones de glucosa y de proteínas totales. Se analizó la actividad de la enzima catalasa, responsable de la degradación del peróxido de hidrógeno, los niveles de tioles totales no proteicos y el daño a lípidos evaluando las especies reactivas al ácido tiobarbitúrico, como indicadores de estrés oxidativo. El estudio se complementó con la obtención del peso de los pingüinos. En general, los parámetros medidos, aumentaron o se mantuvieron constantes desde la primera toma de muestra hasta la última. Si bien algunas de las variables para cada pingüino se comportaron diferentes durante el tratamiento, en general se observó una tendencia a normalizarse hacia el momento de su liberación. Se concluye que los pingüinos se liberaron en buen estado físico luego de la rehabilitación.

Magellanic penguins are among the most affected seabirds by oil contamination in Patagonia. Hydrocarbons and other pollutants cause an increase in the cellular levels of reactive oxygen species that lead oxidative stress and in this way, the evaluation of oxidative stress parameters could be useful tools as biomarkers to evaluate the exposure to hazardous chemical contaminants. The aim of the present work was to evaluate hematological parameters and oxidative stress biomarkers during the rehabilitation of three oil-spill penguins from Punta Tombo Natural Protected Area in Chubut, Argentina. Three blood samples were taken from each individual, the first sample was obtained at arrival of penguin to the rehabilitation center, the second one was the following one week and last sample was taken before animals were freed. Hematocrit, white blood cell count, heterophil/ lymphocyte ratio as a measure of stress, and concentrations of glucose and total proteins were determined. The thiobarbituric acid reactive species, a well-established method for monitoring lipid peroxidation, the activity of catalase enzyme (involved in the catabolism of hydrogen peroxide) and the thiol levels were evaluated as oxidative stress indicators. In general, the measured parameters remained constant or increased their values from the first to the last blood sampling. While some of the variables for each penguin behaved differently during treatment, generally they tended to normalize when penguins were released. We conclude that penguins were released in good physical condition after rehabilitation.

Protection of radiation-induced damage to the hematopoietic system, small intestine and salivary glands in rats by JNJ7777120 compound, a histamine H4 ligand.

Based on previous data on the histamine radioprotective effect on highly radiosensitive tissues, in the present work we aimed at investigating the radioprotective potential of the H4R ligand, JNJ7777120, on ionizing radiation-induced injury and genotoxic damage in small intestine, salivary glands and hematopoietic tissue. For that purpose, rats were divided into 4 groups. JNJ7777120 and JNJ7777120-irradiated groups received a daily subcutaneous JNJ7777120 injection (10 mg/kg) starting 24 h before irradiation. Irradiated groups received a single dose of 5 Gy on whole-body using Cesium-137 source and were sacrificed 3 or 30 days after irradiation. Tissues were removed, fixed, stained with hematoxylin and eosin or PAS staining and histological characteristics were evaluated. Proliferative and apoptotic markers were studied by immunohistochemistry, while micronucleus assay was performed to evaluate DNA damage. Submandibular gland (SMG) function was evaluated by methacholine-induced salivation. Results indicate that JNJ7777120 treatment diminished mucosal atrophy and preserved villi and the number of crypts after radiation exposure (240±8 vs. 165±10, P<0.01). This effect was associated to a reduced apoptosis and DNA damage in intestinal crypts. JNJ7777120 reduced radiation-induced aplasia, preserving medullar components and reducing formation of micronucleus and also it accelerated bone marrow repopulation. Furthermore, it reduced micronucleus frequency in peripheral blood (27±8 vs. 149±22, in 1,000 erythrocytes, P<0.01). JNJ7777120 completely reversed radiation-induced reduced salivation, conserving glandular mass with normal histological appearance and reducing apoptosis and atrophy of SMG. JNJ7777120 exhibits radioprotective effects against radiation-induced cytotoxic and genotoxic damages in small intestine, SMG and hematopoietic tissues and, thus, could be of clinical value for patients undergoing radiotherapy.

Therapeutic potential of histamine H4 receptor agonists in triple-negative human breast cancer experimental model.

BACKGROUND AND PURPOSE: The presence of the histamine H4 receptor (H4R) was previously reported in benign and malignant lesions and cell lines derived from the human mammary gland. The aim of this work was to evaluate the effects of H4R ligands on the survival, tumour growth rate and metastatic capacity of breast cancer in an experimental model. EXPERIMENTAL APPROACH: Xenograft tumours of the highly invasive human breast cancer cell line MDA-MB-231 were established in immune deficient nude mice. The following H4R agonists were employed: histamine (5 mg kg⁻¹), clozapine (1 mg kg⁻¹) and the experimental compound JNJ28610244 (10 mg kg⁻¹). RESULTS: Data indicate that developed tumours were highly undifferentiated, expressed H4R and exhibited high levels of histamine content and proliferation marker (PCNA) while displaying low apoptosis. Mice of the untreated group displayed a median survival of 60 days and a tumour doubling time of 7.4 ± 0.6 days. A significant decrease in tumour growth evidenced by an augment of the tumour doubling time was observed in the H4R agonist groups (13.1 ± 1.2, P < 0.01 in histamine group; 15.1 ± 1.1, P < 0.001 in clozapine group; 10.8 ± 0.7, P < 0.01 in JNJ28610244 group). This effect was associated with a decrease in the PCNA expression levels, and also reduced intratumoural vessels in histamine and clozapine treated mice. Histamine significantly increased median survival (78 days; Log rank Mantel-Cox Test, P = 0.0025; Gehan-Breslow-Wilcoxon Test, P = 0.0158) and tumoural apoptosis. CONCLUSIONS AND IMPLICATIONS: Histamine through the H4R exhibits a crucial role in tumour progression. Therefore, H4R ligands offer a novel therapeutic potential as adjuvants for breast cancer treatment.

Histamine modulates salivary secretion and diminishes the progression of periodontal disease in rat experimental periodontitis.

OBJECTIVE: We have recently reported that experimental periodontitis (EP) reduced methacholine-induced submandibular gland (SMG) salivary secretion. The aim of the present study was to determine whether histamine could prevent SMG impairment produced by EP. MATERIALS AND METHODS: Bilateral EP was induced for 2 weeks and histamine treatment (0.1 mg/kg subcutaneously) was started 5 days before the end of the experimental period in male rats. The histamine effects on periodontitis-altered functional and histological parameters of SMG and on periodontal bone loss were evaluated. RESULTS: Histamine treatment partially reversed the methacholine-induced salivation reduction produced by EP while preventing SMG histological damage. Histamine's effect on SMG was associated with an increased proliferation rate (2.2 ± 0.3 vs. 0.2 ± 0.2 proliferative cells per field, P < 0.001). Furthermore, histamine completely prevented enhanced EP-induced apoptosis (1.0 ± 0.4 vs. 60.9 ± 4.6 apoptotic cells per field, P < 0.001). The protective effect exerted by histamine on SMG functionality is associated with attenuation of lingual and vestibular bone loss (0.66 ± 0.04 vs. 0.97 ± 0.06 mm; P < 0.001). CONCLUSIONS: Histamine is able to reduce periodontitis-induced damage to SMG and bone structure.

Histamine prevents functional and morphological alterations of submandibular glands induced by ionising radiation.

PURPOSE: Xerostomia is a common, disturbing side-effect among patients treated with radiotherapy for head-and-neck cancer. The aim of the present work was to investigate whether histamine could prevent salivary gland dysfunction and histological alterations exerted by ionising radiation. MATERIALS AND METHODS: Forty-eight rats were divided into four groups. Histamine and histamine-5 Gy groups received a daily subcutaneous histamine injection (0.1 mg/kg) starting 24 h before irradiation. Histamine-5 Gy and untreated-5 Gy groups were irradiated with a single dose of whole-body Cesium-137 irradiation. Control and untreated-5 Gy groups were given daily saline injections. Three days post irradiation metacholine-induced salivary secretion was measured or animals were sacrificed and submandibular gland (SMG) removed, stained and histological characteristics were evaluated. Proliferation and apoptosis markers were studied by immunohistochemistry. RESULTS: Radiation decreased salivary secretion by 40% in comparison to untreated rats, which was associated with loss of SMG mass, alteration of epithelial architecture, partial loss of secretor granular material, diminished proliferation and a remarkable apoptotic response. In contrast, histamine completely reversed the reduced salivation induced by radiation, conserved glandular mass with normal appearance and preserved the structural organisation of secretor granules. Radiation-induced toxicity is prevented by histamine essentially by suppressing apoptosis of ductal and acinar cells, reducing the number of apoptotic cells per field (19.0 ± 3.8 vs. 106.0 ± 12.0 in untreated animals, P < 0.001), and also by preventing the radiation-induced decrease in cell proliferation. CONCLUSIONS: Histamine prevents morphological and functional radiation-induced damage on SMG, representing a potential radioprotector for treatment of patients undergoing radiotherapy for head and neck malignancies.

Histamine protects bone marrow against cellular damage induced by ionising radiation.

PURPOSE: Based on our previous data on the histamine radioprotective effect on small intestine, in the present work we aimed to determine whether histamine is able to protect bone marrow cells against ionising radiation damage. MATERIALS AND METHODS: 56 mice and 40 rats were divided into four groups. Histamine and histamine-irradiated groups received a daily subcutaneous histamine injection (0.1 mg/kg) starting 24 h before irradiation. Irradiated groups received a single dose on whole-body using Cesium-137 source and were sacrificed three days after irradiation. We evaluated the number of medullar components, bone marrow trophism, oedema, vascular damage, and other histological characteristics and also proliferation markers by immunohistochemistry. RESULTS: Histamine treatment substantially reduced the grade of aplasia, the oedema and vascular damage induced by ionising radiation on bone marrow of mice and rats. Additionally, histamine preserved medullar components increasing the number of megakaryocytes (14.0 +/- 1.0 vs. 7.3 +/- 1.0 in mice; and 9.9 +/- 1.3 vs. 4.1 +/- 1.0 in rats, P < 0.01) and also myeloid (253.4 +/- 37.6 vs. 7.8 +/- 1.5 in mice; and 52.0 +/- 3.7 vs. 31.8 +/- 3.1 in rats, P < 0.01), lymphoid (97.4 +/- 6.5 vs. 19.8 +/- 1.6 in mice; and 23.4 +/- 0.9 vs. 11.7 +/- 2.5 in rats, P < 0.01) and erythroid cells (165.0 +/- 9.1 vs. 8.8 +/- 2.8 in mice; and 27.3 +/- 2.3 vs. 15.6 +/- 3.5 in rats, P < 0.01) per mm(2). This effect was associated with an increased proliferation rate of bone marrow cells. CONCLUSIONS: Histamine reduces ionising radiation toxicity on bone marrow cells being a suitable candidate for use as radioprotector, especially for patients undergoing radiotherapy who are at the risk of bone marrow or small intestine damage.