ABSTRACT
OBJECTIVES: The aim of this study was to investigate the radiological, biomechanical, histopathological and immunohistochemical effects of theranekron on fracture healing in an experimental rat model. MATERIALS AND METHODS: Forty-eight male albino Wistar rats were used. Four groups were formed, with 12 rats in each of theranekron groups 1 and 2, and control groups 1 and 2. After a fracture was created in the right femur of the rats included in the study, fixation was performed with an intramedullary Kirschner wire. Theranekron was administered subcutaneously to theranekron groups 1 and 2 at a dose of 0.3 mg/kg on days 0, 5 and 10. After radiographic analysis of the femurs of theranekron group 1 and control group 1 rats at four weeks of the study was performed, both groups were divided into two equal subgroups (six femurs in each group). Histopathological and immunohistochemical examinations were performed in one subgroup and biomechanical examination in the other subgroup. At the end of six weeks, the rats in theranekron group 2 and control group 2 were evaluated after applying the same procedure as in the fourth week. RESULTS: When the mean radiological scores of the theranekron and control groups were compared, a statistically significant difference was found in favor of the theranekron group at four and six weeks (p=0.028 and p=0.006, respectively). At four weeks, statistically significant higher biomechanical forces were obtained in the theranekron group compared to the control group (p=0.030). In the histopathological evaluation, the inflammation value of the control group at four weeks was statistically significantly higher than the theranekron group (p=0.027). The angiogenesis, osteoblast proliferation, and bone formation values of the theranekron group were significantly higher than the control group (p=0.014, p=0.014, and p=0.005, respectively). At six weeks, the bone formation values of the theranekron group were statistically significantly higher than the control group (p=0.021). The difference between the theranekron group and the control group scores of the immunohistochemical evaluation were statistically significantly different at four and six weeks (p=0.006 and p=0.011, respectively). CONCLUSION: Theranekron may play a role in accelerating fracture healing by reducing acute inflammation process in the early period of fracture union, increasing fracture strength, angiogenesis, osteoblast proliferation, and bone formation.
Subject(s)
Femoral Fractures , Fracture Healing , Animals , Femoral Fractures/diagnostic imaging , Femoral Fractures/drug therapy , Femoral Fractures/surgery , Femur/diagnostic imaging , Inflammation/drug therapy , Male , Rats , Rats, Wistar , Spider VenomsABSTRACT
The aim of this study was to investigate the protective role of Urtica dioica seed (UDS) extract against azoxymethane (AOM)-induced colon carcinogenesis in rats. Thirty-two male Wistar albino rats were divided into four groups: Control, AOM, AOM + UDS, and UDS. The AOM and AOM + UDS groups were induced by AOM (15 mg/kg body weight) subcutaneously once a week for 10 weeks. AOM + UDS and UDS groups additionally received fed with pellets included 30 ml/kg UDS extract. At the end of the trial, blood and colon tissue samples were taken from the rats following necropsy. The gross and histopathological findings revealed that the administration of UDS extract significantly decreased lesions including aberrant cript foci, adenoma, and adenocarcinoma formation both numerically and dimensionally. Immunohistochemically, slight CEA and COX-2, strong Caspase-3 immune-expressions were detected in the group AOM + UDS compared to AOM group. Biochemical examinations indicated that a markedly increase in the malondialdehyde and fluctuated antioxidant defense system constituents levels such as reduced glutathione, glutathione s-transferase, glutathione peroxidase, superoxide dismutase were restored in AOM + UDS group. These results reveal that the UDS may act as a chemopreventive dietary agent, inducing apoptosis, resulting in a significant reduction of colon carcinogenesis.
Subject(s)
Colonic Neoplasms , Urtica dioica , Animals , Azoxymethane/toxicity , Carcinogenesis , Carcinogens/pharmacology , Colon/pathology , Colonic Neoplasms/chemically induced , Colonic Neoplasms/pathology , Colonic Neoplasms/prevention & control , Plant Extracts/adverse effects , Rats , Rats, Wistar , SeedsABSTRACT
Diabetes mellitus (DM) has been treated with herbs for centuries and many herbs reported to exert antidiabetic activity. Laurus nobilis is an aromatic herb belonging to the Lauraceae family, commonly known as bay. This study aimed to investigate the activity of Laurus nobilis leave extracts on histopathological and biochemical changes in ß-cells of streptozotocin (STZ)-induced diabetic rats. Thirty healthy adult male albino rats were included in the study and divided equally into 5 groups for 4 weeks as follow; control group (C), diabetic group (D), diabetic Laurus nobilis extract group (DLN), Laurus nobilis extract group (LN) and diabetic acarbose (DA) group. Histopathologically, D group rats exhibited various degenerative and necrotic changes in their liver, pancreas and kidney, whereas the DLN rats had nearly normal histology. Insulin immunostaining in the pancreatic beta cells was decreased in the D group compared to the C group, whereas the DLN group was similar to the C group. The glucose concentration decreased significantly in both diabetic rats treated with L. nobilis and acarbose (p < 0.05). Additionally, the levels of aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT) and alanine aminotransferase (ALT) enzyme were significantly decreased in both diabetic rats treated with L. nobilis and acarbose, compared to the D group (p Ë 0.05). Outcomes of this study said that leave extracts of L. nobilis has valuable effect on blood glucose level and ameliorative effect on regeneration of pancreatic islets, it also restored the altered liver enzymes, urea, creatine kinase, total protein levels, calcium and ferritin to near normal.
ABSTRACT
The aim of this study was to investigate the chemopreventive effects of juniper berry (JB) oil on azoxymethane (AOM)-induced colon cancer in rats. Thirty-two male Wistar albino rats were allocated into four groups: Control, AOM, AOM + JB, and JB groups. Whereas the control group was fed with standard pellet feed, the AOM and AOM + JB groups were administered of AOM (15 mg/kg body weight) subcutaneously once every 2 weeks for 10 weeks. AOM + JB and JB groups additionally received JB oil (100 µl/kg) orally. At the end of the 16-week experimental period, blood and tissue samples were obtained from the rats following necropsy. The macroscopic findings showed that the application of JB oil significantly decreased adenoma and adenocarcinoma formation both numerically and dimensionally. Immunohistochemically, CEA, COX-2, and Ki-67 immune-expressions decreased, and the immune-expression of caspase-3 increased in AOM + JB treated rats. Additionally, JB oil supplementation ameliorated antioxidant defense systems and lipid peroxidation within the colon tissue of AOM + JB treated rats. These results reveal that the JB oil acted as a chemopreventive dietary agent, inhibiting cell proliferation and COX-2 expression and inducing apoptosis, resulting in a significant reduction in colon tumor formation.
Subject(s)
Azoxymethane , Colonic Neoplasms , Juniperus , Plant Oils , Animals , Azoxymethane/toxicity , Carcinogenesis , Colon , Colonic Neoplasms/prevention & control , Male , Plant Oils/pharmacology , Rats , Rats, WistarABSTRACT
The therapeutic potential and antioxidant capacity of Ferula elaeochytris extract (FE) in the liver, kidney and pancreas of rats with diabetes induced by streptozotocin (STZ) was assessed using biochemistry, histopathology and immunohistochemistry. Forty adult Wistar albino male rats were divided randomly into five groups of eight rats each. The normal control (NC) group was untreated. The diabetes control (DC) group was treated with STZ to induce diabetes. The diabetes + acarbose group (DAC) was treated with STZ, then with acarbose daily for 28 days. The diabetes + FE (DFE) group was treated with STZ, then FE daily for 28 days. DC rats had inflammatory cell infiltration, hydropic degeneration and necrosis, whereas the DFE rats exhibited nearly normal histology. Insulin immunostaining in the pancreatic beta cells was decreased in the DC group compared to the NC group, whereas the DFE group was similar to the NC group. Many serum biomarkers of damage to liver, kidneys or pancreas were elevated in the DC group compared to the NC group; these biomarkers were decreased in the DFE group. The DC group exhibited increased malondialdehyde levels and decreased levels of the antioxidant defense system constituents compared to the NC group. The level of biomarkers the DFE group was close to the NC group. FE exhibited a protective effect against tissue damage owing to its antioxidant activities and to its ability to effect regeneration of ß-cells in STZ induced diabetic rats.
Subject(s)
Diabetes Mellitus, Experimental , Ferula , Animals , Blood Glucose , Diabetes Mellitus, Experimental/chemically induced , Diabetes Mellitus, Experimental/drug therapy , Liver , Pancreas , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Rats , Rats, Wistar , Streptozocin/toxicityABSTRACT
Whether testicular toxicity is mediated by matrix metalloproteinases (MMPs) is an important question that has not been examined. This study investigated the suppressive effect of curcumin and caffeic acid phenethyl ester (CAPE) on oxidative stress, apoptosis, and whether MMPs mediate doxorubicin (DOX)-induced testicular injury. Male rats were randomly divided into eight groups (n = 8 per group). The groups were as follows: sham, dimethyl sulphoxide (100 µL), DOX (3 mg/kg), CAPE (2.68 mg/kg), curcumin (30 mg/kg), DOX+CAPE (3 mg/kg DOX and 2.68 mg/kg CAPE), DOX+curcumin (3 mg/kg DOX and 30 mg/kg curcumin) and DOX+CAPE+curcumin (3 mg/kg DOX, 2.68 mg/kg CAPE and 30 mg/kg curcumin). Injections were administered daily for 21 days. The oxidative stress, MMPs, proinflammatory cytokines and apoptotic markers in the DOX group were higher than the sham group (p < .05); these measures were lower in the groups treated with CAPE and curcumin together with DOX compared with the DOX group (p < .05). The results showed that MMPs mediated DOX-induced testicular injury, but CAPE and especially curcumin suppressed testis injury and cell apoptosis by suppressing DOX-induced increases in MMPs, oxidative stress and proinflammatory cytokines. However, curcumin exhibited more pronounced effects than CAPE in terms of all studied parameters.
ABSTRACT
INTRODUCTION: This study determined the presence of nitric oxide synthesis isoforms (nNOS, iNOS, and eNOS) in thoracic spinal cord segments and nodose ganglia of rats with gamma-irradiated livers. MATERIAL AND METHODS: Male rats (n = 32) were divided into equal groups A, B, C, and D. In group A, the controls, no radiation was applied, while groups B, C, and D received 10 Gy of ionising gamma radiation. The rats of group B were euthanized at the end of the first day (d1), those of group C on the second day (d2), and those of group D on the third day (d3). The liver, spinal cord segments, and nodose ganglion tissues were dissected and fixed, and the liver sections were examined histopathologically. The other tissues were observed through a light microscope. RESULTS: Regeneration occurred at the end of d3 in hepatocytes which were radiation-damaged at the end of d1 and d2. On d1, some nNOS-positive staining was found in the neuronal cells of laminae I-III of the spinal cord and in neurons of the nodose ganglion, and on d3, some staining was observed in lamina X of the spinal cord, while none of note was in the nodose ganglion. Dense iNOS-positive staining was seen on d1 in the ependymal cells of the spinal cord and in the glial cells of the nodose ganglion, and on d3, there was still considerable iNOS staining in both tissues. There was clear eNOS-positive staining in the capillary endothelial cells of the spinal cord and light diffuse cytoplasmic staining in the neurons of the nodose ganglion on d1, and on d3, intense eNOS-positive staining was visible in several endothelial cells of the spinal cord, while light nuclear staining was recognised in the neurons of the nodose ganglion. CONCLUSION: The nNOS, iNOS, and eNOS isoforms are activated in the spinal cord and nodose ganglion of rats after ionising radiation insult to the liver.
ABSTRACT
Radiotherapy is often used for the treatment of cancer. However, it causes some side effects in patients. This study aimed to determine the hepatoprotective effects of Urtica dioica L. seed-extract (UDSE) in radiation-induced liver injury. Thirty-two male rats were randomly divided into 4 groups (n=8): control(C) group: no action was taken; radiation (R) group: irradiation was administrated at 5Gy single-fraction, radiation with UDSE(R+UDSE) group: irradiation was administrated at 5 Gy single-fraction and animals were fed pellets with 30 mL UDSE/kg; UDSE group: animals were fed pellets with 30 mL UDSE/kg. All of the experiments were performed in all of the groups over 10 days. Malondialdehyde (MDA) and reduced-glutathione (GSH) levels and superoxide-dismutase (SOD), catalase (CAT), glutathione-peroxidase (GSH-Px), aspartate-transaminase (AST), and alanine-aminotransferase (ALT) activities were determined. Histopathological findings were also evaluated in liver tissues. SOD, CAT and GSH-Px activities and GSH levels in the serum and liver were significantly increased, while MDA levels decreased in the R+UDSE group compared with the R group (P<0.05). Moreover, AST and ALT serum activities in the R+UDSE group were lower than those in the R group (P<0.05). In addition, radiation induced degenerative/necrotic changes in the R group were significantly compensated in the R+UDSE group. The results showed that radiation increased oxidative stress and decreased antioxidant capacity, as well as degeneration in the liver. However, UDSE attenuated these degenerative changes.
ABSTRACT
This study was conducted on 28 male Wistar albino rats to determine the effects of chrysin on methotrexate-induced damage to testicular tissue. Rats were grouped into four groups of seven rats reach: Group 1 (n = 7) was the control group to which no drugs were administered; this group was only provided with food and water. Group 2 (n = 7) was administered 20 mg/kg of methotrexate once intraperitoneally. Group 3 (n = 7) was administered 50 mg/kg of chrysin for 7 days orally. Group 4 (n = 7) was administered 20 mg/kg of methotrexate once intraperitoneally, followed by oral administration of 50 mg/kg of chrysin for 7 days. At the end of the experiment, rats were anaesthetised, rat testes were removed, and spermatozoon was obtained from the cauda epididymis. It was determined that sperm count and motility, glutathione peroxidase, superoxide dismutase and catalase activities decreased in the methotrexate group, whereas malondialdehyde, tumour necrosis factor-α, interleukin-1ß and nuclear kappa factor B expression levels increased. Furthermore, damage to tubulus seminiferus structures and affusion in germ cells was identified. In the methotrexate + chrysin administered group, sperm count improved, biochemical enzyme levels increased, and structural improvements were observed in testicular tubules. These findings demonstrated that chrysin plays a protective role in testicular damage in rats.
Subject(s)
Antioxidants/pharmacology , Flavonoids/pharmacology , Methotrexate/toxicity , Oxidative Stress/drug effects , Protective Agents/pharmacology , Sperm Motility/drug effects , Testis/drug effects , Animals , Catalase/metabolism , Epididymis/drug effects , Epididymis/metabolism , Glutathione Peroxidase/metabolism , Male , Malondialdehyde/metabolism , Rats , Rats, Wistar , Sperm Count , Superoxide Dismutase/metabolism , Testis/metabolismABSTRACT
INTRODUCTION: The aim of this study was to determine the predisposing effect of bovine respiratory syncytial virus (BRSV) on Pasteurella spp. infection in naturally-induced pneumonia in cattle by immunohistochemical labelling. MATERIAL AND METHODS: Lungs of cattle slaughtered in the slaughterhouse were examined macroscopically, and 100 pneumonic samples were taken. The samples were fixed in 10% neutral formalin and embedded in paraffin by routine methods. Sections 5 µm in thickness were cut. The streptavidin-peroxidase method (ABC) was used to stain the sections for immuno-histochemical examination. RESULTS: BRSV antigens were found in the cytoplasm of epithelial cells of bronchi, bronchioles, and alveoles and within inflammatory cell debris and inflammatory exudate in bronchial lumens. Pasteurella spp. antigens were detected in the cytoplasm of the epithelial cells of bronchi and bronchioles, and in cells in the lumens of bronchi and bronchioles. Eleven cases were positive for only one pathogen (six for BRSV and five for Pasteurella spp.), while 35 cases were positive for 2 pathogens: BRSV plus P. multocida (n = 21) or M. haemolytica (n = 14). CONCLUSION: The presence of high levels of BRSV in dual infections indicates that BSRV may be the main pneumonia-inducing agent and an important predisposing factor for the formation of Pasteurella spp. infections in cattle naturally afflicted with pneumonia.
ABSTRACT
Abstract The present study aimed to investigate the protective effects of silymarin (SMN), an antioxidant, on methotrexate (MTX)-induced damage in rat testes. Thirty-two Wistar albino rats were divided into four groups (n = 8): control, MTX (20 mg/kg, i.p. on days 1 and 5), SMN (200 mg/kg, orally), and MTX + SMN (20 mg/kg, i.p. on days 1 and 5 and SMN 200 mg/kg orally) groups. At the end of the 6-week trial period, histopathological, immunohistochemical, biochemical, and spermatological analyses were performed on testes tissues. Histopathologically, MTX-induced damage, including depletion of germ cell and loos of spermatozoa, was significantly improved with SMN treatment. Immunohistochemically, the immunoreactivity of glutathione peroxidase 1 (GPx1) and manganese superoxide dismutase 2 (SOD2) were detected more intensely in the MTX + SMN group than in the MTX group. Biochemical examinations revealed that SMN supplementation decreased the lipid peroxidation and increased enzymatic antioxidants in the SMN-treated rats. Spermatologically, significant differences were found in the density, motility, dead-to-live sperm ratio, and abnormal sperm rate in the MTX + SMN group compared to the MTX group. In conclusion, SMN seems to have protective effects as an antioxidant against MTX-induced damage in rat testes.
Subject(s)
Animals , Male , Rats , Silymarin/adverse effects , Testis/abnormalities , Protective Agents/analysis , Methotrexate/analysisABSTRACT
BACKGROUND: Natural honey (honey) is considered as a part of traditional medicine all over the world. It has both antimicrobial and antioxidant properties, useful in stimulation of wounds and burns healing and gastric ulcers treatment. The aim of this study, for the first time, was to investigate the antioxidant properties and protective role of honey against carcinogen chemical aflatoxin (AF) exposure in rats, which were evaluated by histopathological changes in liver and kidney, measuring level of serum marker enzymes [aspartate aminotransferase (AST), alanin aminotransferase (ALT), gamma glutamil transpeptidase (GGT)], antioxidant defense systems [Reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)], and lipid peroxidation content in liver, erythrocyte, brain, kidney, heart and lungs. METHODS: Eighteen healthy Sprague-Dawley rats were randomly allocated into three experimental groups: A (Control), B (AF-treated) and C (AF + honey-treated). While rats in group A were fed with a diet without AF, B, and C groups received 25 µg of AF/rat/day, where C group additionally received 1 mL/kg of honey by gavage for 90 days. RESULTS: At the end of the 90-day experimental period, we found that the honey supplementation decreased the lipid peroxidation and the levels of enzyme associated with liver damage, increased enzymatic and non-enzymatic antioxidants in the AF + honey-treated rats. Hepatoprotective and nephroprotective effects of honey is further substantiated by showing almost normal histological architecture in AF + honey-treated group, compared to degenerative changes in the liver and kidney of AF-treated rats. Additionally, honey supplementation ameliorated antioxidant defens systems and lipid peroxidation in content in other tissues of AF + honey treated rats. CONCLUSION: The present study indicates that honey has a hepatoprotective and nephroprotective effect in rats with experimental aflatoxicosis due to its antioxidant activity.
Subject(s)
Aflatoxins/toxicity , Honey , Protective Agents/pharmacology , Animals , Body Weight/drug effects , Kidney/drug effects , Kidney/pathology , Liver/drug effects , Liver/pathology , Male , Malondialdehyde , Necrosis/chemically induced , Necrosis/pathology , Protective Agents/chemistry , Rats , Rats, Sprague-DawleyABSTRACT
Clothianidin (CTD) is a novel, broad-spectrum insecticide. In the current study, it was aimed to study the effect of subchronic exposure to low doses of CTD (2, 8 and 24 mg/kg body weight/day) on the reproductive system in adult rats. CTD treatment did not significantly change serum testosterone level or sperm parameters (e.g. concentration, motility and morphology), but caused significant decreases in weights of epididymis, right cauda epididymis and seminal vesicles. CTD treatment did not cause sperm DNA fragmentation and did not change the apoptotic index in the seminiferous tubules and levels of α-tocopherol and glutathione, but increased the level of thiobarbituric acid-reactive substances and cholesterol levels significantly at all doses. CTD exposure caused significant elevations in palmitic, linoleic and arachidonic acids in testis in all CTD-exposed groups. There was a drop in 20:4/18:2 (arachidonic acid/linoleic acid) ratio and an increase in 18:1n-9/18:0 (oleic acid/stearic acid) ratios in all CTD groups, in comparison to the control group. In conclusion, CTD had little detectable detrimental effects on the reproductive system of male rats over the measured parameters.
Subject(s)
Genitalia, Male/drug effects , Guanidines/toxicity , Insecticides/toxicity , Thiazoles/toxicity , Analysis of Variance , Animals , Cholesterol/metabolism , DNA Fragmentation/drug effects , Dose-Response Relationship, Drug , Epididymis/drug effects , Glutathione/metabolism , Male , Neonicotinoids , Rats , Seminal Vesicles/drug effects , Spermatozoa/drug effects , Testosterone/blood , Thiobarbituric Acid Reactive Substances/metabolism , Toxicity Tests , alpha-Tocopherol/metabolismABSTRACT
This study was carried out to investigate the hepatoprotective and antioxidant properties of Urtica dioica L. seeds (UDS) extract against aflatoxin (AF)-exposure in rats. The preventive potential and antioxidant capacity of the plant's extract was evaluated by liver histopathological changes, measuring serum marker enzymes, antioxidant defense systems and lipid peroxidation (Malondialdehyde, MDA) content in some tissues of rats. Eighteen rats were randomly divided into one of three experimental groups: control, AF-treated group and AF+UDS-treated group. Rats in control group were fed with a diet without AF. Rats in AF-treated group and AF+UDS-treated group received approximately 25 microgr of AF/rat/day. AF+UDS groups also received 2 mL of UDS oils/rat/day by gavage for 90 days. Administration of UDS extract restored the AF-induced imbalance between MDA and antioxidant system towards near normal particularly in liver. Hepatoprotection by UDS is further substantiated by the almost normal histologic findings in AF+UDS-treated group as against degenerative changes in the AF-treated rats. It is concluded that UDS has a hepatoprotective effect in rats with aflatoxicosis, probably acting by promoting the antioxidative defense systems.
Subject(s)
Antioxidants/pharmacology , Chemical and Drug Induced Liver Injury/prevention & control , Lipid Peroxidation/drug effects , Liver/drug effects , Plant Extracts/pharmacology , Urtica dioica/chemistry , Administration, Oral , Aflatoxins/toxicity , Animals , Antioxidants/chemistry , Body Weight/drug effects , Chemical and Drug Induced Liver Injury/blood , Chemical and Drug Induced Liver Injury/etiology , Chemical and Drug Induced Liver Injury/pathology , Disease Models, Animal , Erythrocytes/drug effects , Erythrocytes/metabolism , Hepatocytes/drug effects , Hepatocytes/metabolism , Hepatocytes/pathology , Liver/pathology , Liver Function Tests , Male , Malondialdehyde/metabolism , Oxidoreductases/metabolism , Plant Extracts/chemistry , Poisons/toxicity , Rats , Rats, Sprague-Dawley , Seeds/chemistryABSTRACT
Brucella melitensis, a worldwide zoonotic pathogen, is a significant cause of abortion in sheep and goats in some countries. The present study was carried out to determine, by immunohistochemistry, the presence of B. melitensis antigens in 110 naturally occurring aborted sheep fetuses. Sections of lung, liver, kidney, and spleen of each fetus were stained with immunoperoxidase to detect Brucella antigens. Brucella melitensis antigens were detected in 33 of 110 fetuses (30%). In the 33 positive cases, Brucella antigens were found in lung (25 [22.7%]), liver (21 [19%]), spleen (13 [11.8%]), and kidney (6 [5.4%]). Microscopic studies demonstrated that Brucella antigens were mainly located in the cytoplasm of macrophages and neutrophils of the lung, and in the cytoplasm of macrophages in the portal infiltrates and Kupffer cells of the liver. It was concluded that immunohistochemistry in formalin-fixed, paraffin-embedded tissues is a useful tool for the diagnosis of spontaneous ovine abortion caused by B. melitensis.
Subject(s)
Abortion, Induced/veterinary , Antigens, Bacterial/blood , Brucella melitensis/immunology , Brucellosis/diagnosis , Sheep Diseases/diagnosis , Animals , Antigens, Bacterial/analysis , Brucellosis/pathology , Female , Immunohistochemistry , Pregnancy , Sheep , Sheep Diseases/pathologyABSTRACT
This experiment was carried out to investigate the effect of N. sativa L. on histopathology of pancreatic beta-cells, and blood insulin and glucose concentrations in streptozotocin-induced diabetic rats. Fifty male Wistar rats (200-250 g) were divided into two experimental groups (diabetics with no treatment and diabetics with N. sativa L. treatment), each containing twenty-five rats. Diabetes was induced in both groups by a single intraperitoneal injection of streptozotocin (STZ) (50 mg/kg). The experimental animals in both groups became diabetic within 24 hours after the administration of STZ. The rats in N. sativa L.-treated group were given the daily intraperitoneal injection of 0.20 ml/kg of N. sativa L. volatile oil for 30 days starting the day after STZ injection. Control rats received only the same amount of normal saline solution. The rats in both groups received the last injection 24 hours before the sacrification and 5 randomly-selected rats in each group were sacrificed before, and the 1, 10, 20 and 30 days after the STZ injection to collect blood and pancreatic tissue samples. The N. sativa L. treatment caused a decrease in the elevated serum glucose, an increase in the lowered serum insulin concentrations and partial regeneration/ proliferation of pancreatic beta-cells in STZ-induced diabetic rats with the elapse of the experiment. It is concluded that the hypoglycaemic action of N. sativa L. could be partly due to amelioration in the beta-cells of pancreatic islets causing an increase in insulin secretion. More studies are needed to demonstrate the exact mechanism of action of N. sativa L. on ameliorated blood glucose concentration in STZ-induced diabetes.