BACKGROUND:In the studies focusing on diabetic organisms, Streprozotocine (STZ) is a frequently used agent to induce diabetes in rats and mice. However the current studies do not represent practical importance of their statistical findings. For showing practical importance of the differences in plasma insulin levels of diabetic rats and mice induced by STZ, there should be a statistical synthesis regarding statistical findings of the studies.AIM:The purpose of this study is to make a meta-analysis of the studies on the effect of STZ on plasma insulin levels in diabetic rats and mice.MATERIALS AND METHODS:In this study 39 effect sizes (37 studies) about levels of plasma insulin were analyzed by calculating individual effect sizes (d) and mean effect size.RESULTS:The effect sizes were between -13.7 and +65.3 and the mean effect size value (+9.33) represented a large effect indicating that STZ was an effective agent to significantly decrease plasma insulin levels of diabetic rats and mice.CONCLUSION:It can be said that the differences in plasma insulin levels between STZ-applied and no application groups has a practical importance in making animal model of diabetes.

No abstract

The purpose of the study was to investigate the effects of Exendin-4 on polycystic ovary syndrome (PCOS) in rats in chronic mild stress medium. For establishing the PCOS model, dehydroepiandrosterone (DHEA) (6mg/100g) in 0.2ml sesame oil was injected subcutaneously to 21-day old rats (n = 67). In addition, 0.2ml sesame oil was injected subcutaneously to the rats in groups involving solution injection only. At the initial stage of the study, the rats were grouped as control, solution and PCOS, whereas stress and Exendin-4 groups were also added in the second stage of the study. In PCOS groups, Exendin-4 was applied intraperitoneally (10μg/kg/day) in mild chronic stress medium for four weeks. The results revealed that weight, fasting blood glucose, fasting blood insulin and HOMA-IR levels in the rats with PCOS were significantly higher than in the other groups; also, corticosterone levels of stress groups were significantly higher than in the other groups. In addition, harmful effects of PCOS on ovarian tissues were observed in histological examinations. However, after Exendin-4 application in PCOS groups, weight, fasting blood glucose, fasting blood insulin, HOMA-IR and LH/FSH levels were decreased, whereas Exendin-4 application in PCOS group treated with stress was not as effective as the application of Exendin-4 on rats with PCOS. Exendin-4 application also increased the number of healthy follicles in PCOS group, whereas there was no change in the number of healthy follicles in PCOS+Stress group.

Investigating effects of grape seed extract on neuropathic pain in the streptozotocin-induced diabetic mice. Yurt A., Köksal B., Gürbüz P., Yıldız A., Vardı N., Alçin E. Diabetes mellitus is a complicated and serious health problem involving peripheral neuropathy. This situation causes to loss of senses, tingle and pain. Diabetic peripheral neuropathy (DPN) affects 236 million people around the World. Hence there is a need to investigate alternative ways of cure focusing on DPN. Flavonoids have potential on pain due to their permeability characteristic in the capillary microcirculation system and in lowering blood pressure. Flavonoids are common in grape seed. The main flavonoids of grape seed involve proanthocyanidins which might be an effective agent in cure of pain in DPN. The purpose of this study is to investigate effects of grape seed extract on neuropathic pain in the Streptozotocin-induced diabetic mice. In the study, 50 eight-week old BALB-C strain mice in five different groups (Control, Diabetic Control, Control+25 mg/kg, Diabetes+25 mg/kg and Diabetes+50 mg/kg) were used. To induce diabetes in thirty of these animals, single dose Streptozotocin (180 mg/kg) was administered intraperitoneally. After diabetes was observed, grape seed extract (25 mg/kg and 50 mg/kg body weight) was administered by oral gavage in three groups (Control+25 mg/kg, Diabetes+25 mg/kg and Diabetes+50 mg/kg) during six weeks. At the end of the second and sixth weeks, pain threshold measurements in hot plate test were performed in line with a predetermined thermal pain model. Also the tissues of the sciatic nerve and abdominal aorta from the animals were histologically investigated. As a result hot plate measurements, pain threshold values of the animals in Diabetes+50mg/kg group significantly differed from the measurements of the animals in control group in the first measurements and from the animals in Diabetes+25 mg/kg group in the second measurements (p<0.05). However pain threshold values of the animals in Diabetes+25 mg/kg group differed significantly from the values of the animals in control+25 mg/kg group and control group. It means pain threshold values of the animals in Diabetes+50 mg/kg and Diabetes+25 mg/kg groups were significantly lower than the values of the animals in the other groups. The results of histological investigations showed that degenerations of myelin sheet and axons in diabetic control group were decreased significantly in Diabetes+50 mg/kg and Diabetes+25 mg/kg groups. Moreover degenerations of aorta tissues of animals in diabetic group were not seen in the animals of Diabetes+50 mg/kg except for tunica adventitia inflammation. It can be said that grape seed extract decreased threshold of neuropathic pain in the Streptozotocin-induced diabetic mice and prevented degenerations of myelin sheet and axons, and aorta tissues.

IntroductionDetermining differences and patterns in the responses might lead to understand over-excitability of students with high cognitive ability and to design treatments for helping them in controlling stress.Material and methodsA comparative research method was used with three different instruments. The data were analyzed by t-test and Welch’s F-test.ResultsThe SHCA reported significantly higher frequencies of psychological stress responses whereas they expressed significantly lower frequencies of physiological stress responses than their counterparts.cantly lower frequencies of physiological stress responses than their counterparts.ConclusionsThese findings might lead to a discussion about the factors determining differences in the responses given by students with high cognitive ability under stress conditions.