Clinical evolution of diabetic rats after transplant of electrofused pancreatic islet cells and dermic cells.

This work was designed to study an alternative treatment of diabetes mellitus by using a transplant of hybrid cells obtained by the electrofusion of pancreatic islet cells from a healthy donor with dermic cells obtained from a recipient. The hybrid cells kept the capacity of insulin production, its regulation, and the natural control of glycemia, as well as the factors of histocompatibility to avoid the rejection. Four groups of four rats each were established: Group 1. Healthy animals (healthy control), Group 2. Diabetized non-treated animals (diabetic control), Group 3. Transplant recipient rats with extraction of dermic cells which were mixed with pancreatic insular cells from a healthy donor (transplant without fusion), and Group 4. Transplant recipient rats, with extraction of dermic cells which were electrofused with pancreatic insular cells from a healthy donor (transplant with fusion). For the Group 4, the cells were combined and they were submitted to dielectrophoresis conditions with an alternating current pulse of 15 s of 10 V RMS of 0.5 MHz. The fusion was made with a direct current pulse of 1 ms of 300 V. Clinical signs were registered (weight, diuresis, food and water intake), and several biochemical parameters in blood which included basal glycemia, uric acid, cholesterol, triglycerides, glutamate oxalacetate transaminase, glutamate pyruvate transaminase, urea, creatinine, insulin, glycated hemoglobin were registered. Additionally, ketone bodies and glucose were also measured in urine. All determinations were made at 30, 60, and 90 days. Animals of Group 1 maintained its parameters within the normal ranges. Rats of Group 2 presented alterations corresponding to a diabetic state in almost all the parameters measured, none of the animals showed a tendency to improve spontaneously, two of the rats died at 66 and 72 days. The Group 3 showed a clinical profile similar to the diabetic control group without improvement, only one rat died at day 33, while in the rats transplanted with fusion (Group 4) an improvement was observed on some parameters including body weight, water intake and glycemia. Although insulin concentration was under the normal range, it was higher than in the Group 3. None rat died. These results indicate that it is possible to improve the diabetic profile by the transplant of dermic cells from a diabetic animal fused with insular cells from a healthy donor in the recipient animal.

A model for the induction of aplastic anemia by subcutaneous administration of benzene in mice.

Long-term exposure to benzene vapors is associated with hematological diseases such as leukemia, lymphoma and aplastic anemia. CD(1) male mice were randomly assigned to six groups: 1B(10), 1B(15), 1B(20), 2B(10), 2B(15), and 2B(20.) 1B mice were administered 2 ml/kg (1940 mg/kg) subcutaneous injection (in the dorsal region) of benzene 5 days a week, and 2B mice were exposed 3 days a week (Monday, Wednesday and Friday) until a total of 10, 15 and 20 doses were completed. About 48 h after treatment completion, leukocyte, erythrocyte, and bone marrow cells were counted, and spleen histopathology was analyzed. 1B(15) and 1B(20) mice showed lethargy and irritability, 80% body and 42% spleen weight loss (P<0.001), while body and spleen weight loss were less severe in 2B mice (12 and 48%, respectively). After exposure to 20 benzene doses, 1B(20) and 2B(20) mice showed decreased hemoglobin concentrations, and erythrocyte, leukocyte and bone marrow cell counts (37, 34, 80 and 50%, respectively in group 1B(20); P<0.001; and 12, 48, 62 and 62%, respectively in group 2B(20)). Thrombocytopenia occurred only in group 2B. Both benzene-treatment schemes caused aplastic anemia, however, the disease was masked by spleen toxicity in group 1B. Scheme 2 allowed mice survival and caused less non-hematological effects. We establish here a reproducible and inexpensive experimental model to induce aplastic anemia in mice by subcutaneous injection of 2 ml/kg benzene, using two short-term treatment schemes.

[Aplastic anemia: a model for its induction by oral and subcutaneous benzene in rats]. / Anemia aplástica: modelo para su inducción con benceno por vía oral y subcutánea en ratas.

PURPOSE: To set up the experimental conditions to induce aplastic anaemia in rats by oral and subcutaneous administration of benzene. MATERIAL AND METHODS: 6 groups with 6 male Wistar rats weighting 150 g each were formed. Each group with different conditions; 3 of them as experimental groups: 1) ES group (benzene 2 mL/Kg supplied subcutaneously), 2) EOI and 3) EOII groups (benzene 1.14 and 2 mL/Kg supplied orally); and 3 groups as control: 4) TS and 5) TO groups (supplied only with the vehicle subcutaneously. and orally, respectively) and 6) C group without treatment. Benzene was supplied during four weeks. Blood counts were done at 0, 15 and 30 days of treatment. EOI and EOII treatment was interrupted because of a severe damage to rats and the other groups except TO group continued until 60 days. When the treatment ended haematological determinations continued for 60 days every two weeks including osmotic fragility test and bone marrow smears in order to observe permanent changes. RESULTS: The rats treated with benzene 4 weeks showed a reduction in concentration of haemoglobin, bleeding of nasal and gastric mucosae, thrombocytopenia, microcytosis and macrocytosis in EOI and EOII groups respectively. The animals treated with benzene 60 days (ES) showed persistent reduction in haemoglobin and platelet concentration, macrocytosis and lymphopenia until day 60. On the other hand, the neutrophil concentration kept lower than the controls after day 75. In these animals blast cells and increased peroxidase positive cells were seen in peripheral blood. Also an increased osmotic fragility of erythrocytes was observed and the bone marrow exhibited deep hypocellularity until day 120. CONCLUSION: The administration of benzene subcutaneously damaged irreversibly the myeloid progenitor cells, causing permanent reduction in concentration of erythrocytes, platelets and neutrophils. These results are similar to those reported with the inhalatory exposition to benzene. With the method here assayed long periods of treatment and expensive and sophisticated experimental conditions are avoided.