Day Of Streptozotocin Administration Research Articles

Role of Onset of Diabetes on Development of Cognitive Impairment in Rats

AbstractBackgroundThe risk of cognitive impairment in diabetic patients is increasing in day to day life. One of the reasons for cognitive impairment in diabetic patients is hyperglycemic condition. Hyperglycemia leads to amyloid beta accumulation in brain, aggravates oxidative stress, neuro‐inflammation, and results in mitochondrial dysfunction, which impairs neuronal integrity, and eventually neurodegeneration. These are possible working mechanisms in diabetes‐related cognitive impairment. Further, literature says that, earlier the development of diabetes, greater the chances of developing cognitive impairment.MethodDiabetes was induced using streptozotocin in juvenile (3‐6 weeks old), adult (8‐10 weeks old) and aged (30‐34 weeks old) rats. Blood glucose levels were monitored after 10 days of streptozotocin administration. Rats which showed cognitive impairment were treated with insulin or insulin + donepezil. Diabetic rats were evaluated for cognitive impairment in fear conditioning memory task at 3 and 6 weeks after the confirming diabetes.ResultThe total freezing time decreased in juvenile> adult > aged diabetic rats respectively, when compared with naïve rats. The cognitively impaired diabetic rats treated with insulin + donepezil showed improvement in the associative memory observed from increase in freezing behavior in fear conditioning task.ConclusionDiabetes in the early stages of life may have greater risk for developing cognitive impairment.

Influence of Diabetes on Morphometric Index of Ovarian Follicles in Streptozocin-Induced Rats

The study aimed to determine the effect of diabetes on follicle development by measuring the diameters of rats' ovarian follicles. The structure and function of many organs change by being affected by diabetes. The ovary is an essential organ of the reproductive system affected by diabetes. The size of the ovarian follicles and corpus luteum can also be affected by diabetes. For this reason, body mass, blood glucose level, and rat ovarian follicles, and corpus luteum diameters were measured in this study. Ten healthy female rats were kept as the control group. In the other rat group, experimental diabetes was induced with streptozotocin (STZ)(60 mg/kg). The rats in both groups were killed after 30 days and their ovaries removed. 5-6 µm sections were made using paraffin embedding techniques and stained with hematoxylin-eosin. On the fifth day of STZ administration to rats, the mass loss of rats was 10%, and the diabetogenic index was 330%. Compared with the control group, diameters of diabetic rats significantly decreased the diameter of the primordial, primary and Graafian follicles, and corpus luteum. The decrease in the diameter of secondary follicles of diabetic rats was not significant. The percentage shrinkage index was the highest in the corpus luteum with 37%. As a result, it can be said that diabetes influences the size of the ovarian follicles and especially the corpus luteum, thereby negatively affecting the ability to improve oocyte quality. Diabetes-related follicle diameter may shrink and cause infertility. It may be essential to measure the diameters of the follicles in vitro fertilization studies in patients with diabetes.

Treatment of streptozotocin-induced diabetic rats with Castanea sativa and Lactarius deterrimus extracts decreases liver damage by initiating activation of the Akt prosurvival kinase

Diabetes is the most important non-infectious disease affecting 5% of the general population. Different plant and mushroom extracts with hypoglycemic and antioxidant properties have been used traditionally as antidiabetic herbal medicines. The aim of this study was to study the in vivo effect of extracts obtained from the edible mushroom, Lactarius deterrimus (Ld), and chestnut, Castanea sativa (Cs), on the alleviation of liver damage in streptozotocin (STZ)-induced diabetic rats. The extracts were applied, either alone or in combination, for four weeks, starting from the last day of STZ administration. Diabetic rats treated with the extracts exhibited reduced hyperglycemia and lower hepatic oxidative stress. Extract treatment decreased the level of O-linkage of N-acetylglucosamine modified superoxide dismutase, catalase and NF-?B. Masson trichrome staining showed a decrease in collagen fiber deposition in the liver. Immunoblot analysis revealed the activation of the prosurvival Akt kinase after extract application. The obtained results revealed that the hyperglycemiareducing and antioxidant effects of the Ld and Cs extracts suppressed cytotoxic signaling pathways, attenuating the negative effects of diabetes on the liver. The examined extracts are beneficial in the prevention of liver damage and could be considered for prediabetes and diabetes management after a definitive phytochemical description of extract constituents and subsequent evaluation in preclinical and clinical studies.

Effect of leptin on spatial learning, memory and blood glucose level in streptozotocin induced diabetes mellitus in male wistar albino rats

Background: Diabetes mellitus is known to cause cognitive impairment that can be possibly attributed to deficient levels of leptin in diabetic animals. This study was undertaken to study the effect of administration of leptin on spatial learning, memory and blood glucose levels in diabetic rats.Methods: Rats were divided into three groups. The first group was the control group. Diabetes was induced in groups 2 and 3 by streptozotocin (STZ) injection (60 mg/kg) intraperitoneally. Group 2 received saline while group 3 received leptin (0.1 mg/kg) subcutaneously for 10 days from 4th day of STZ administration. Behavioural assessment was done in T maze after 21 days of the last injection of leptin. Blood glucose levels were also analysed.Results: The number of correct arm entries decreased while time spent being immobile and time spent to reach the correct arm increased in the diabetic group when compared to the control group and correct arm entries increased while time spent immobile and time spent to reach the correct arm decreased with leptin treatment when compared to the diabetic control rats. Blood glucose levels increased in the diabetic rats while leptin administration reduced blood glucose levels in the group 3.Conclusions: Our study suggests that leptin can improve learning and memory while also producing a slight reduction in the blood glucose levels in diabetic rats.

Anti-oxidant, anti-apoptotic, anti-hypoxic and anti-inflammatory conditions induced by PTY-2 against STZ-induced stress in islets.

The earlier assessment of Pueraria tuberosa (PT) has shown anti-diabetic effects through enhancing incretin action and DPP-IV (Dipeptidyl peptidase-IV) inhibition. The aim of this work was to further explore the protective role of aqueous extract of Pueraria tuberosa tuber (PTY-2) against streptozotocin (STZ) induced islet stress in rats. Diabetes was induced by STZ (65 mg/kg body weight) in charles foster male rats. After 60 days of STZ administration, animals with blood glucose levels > 200 g/dL were considered as diabetic. All the rats were later divided into three groups: Group-1 (STZ untreated normal rats), Group-2 (Diabetic control), and Group-3 (PTY-2 [50 mg/100 g bw treatment for next 10 days to diabetic rats). The rats were then sacrificed after the 10th day of treatment accordingly. STZ treatment led to an increase in expression of Matrix metalloproteinases-9 (MMP-9), Tumour necrosis factor-α (Tnf-α), Hypoxia inducible factor-α (HIF-1α), Vascular endothelial growth factor (VEGF), Interleukin-6 (IL-6), Protein kinase C-ε (PKC-ε), Nuclear factor kappa-light-chain-enhancer of activated B-cells (NFkB), and Caspase-3. Reverse Transcriptase-PCR (RT-PCR), Immunohistochemistry and Western-Blot analysis showed an increase in the expressions of Superoxide Dismutase (SOD) and Nephrin, and a decrease in the expressions of NFkB, PKC-ε, TNF-α, MMP-9, HIF-1α, VEGF, Caspase-3 and IL-6 after 10 days of PTY-2 treatment. The results showed that PTY-2 favorably changed all the expressions via anti-oxidant, anti-apoptotic, anti-hypoxic and anti-inflammatory pathways, making itself as a protective agent against STZ induced islet stress. Further evaluation of PTY-2 might be helpful in establishing its role in the management of diabetes mellitus.

The Ameliorative Potential of Saffron Against the Histological and Immunohistochemical Changes in Kidney of Albino Mice Due to Streptozotocin-Induced Diabetes Mellitus

Background: multiple-organ failure is the chief inducer of death in diabetes mellitus and hyperglycaemiainduced oxidative stress is responsible for serious complications including nephropathy. Medicinal plants with antioxidant activity may ameliorate oxidative status and improve the histological and immunohistochemical lesions resulted in chronic hyperglycemia in diabetes. Aim of the work: this study aimed to assess the beneficial effects of aqueous saffron extract (ASE) in streptozotocin (STZ)-induced diabetic mice by investigating the histopathological and immunohistochemical pattern in kidney tissues of different experimental groups. Material and Methods: fasted mice were intraperitoneally (IP) injected by a single dose of a STZ (60 mg/kg body weight). After 24 hours, animals with fasting blood glucose over than 300 mg/dl were considered diabetic. The experimental groups were; control (1), saffron (2), diabetic (3) and diabetic + saffron (4). The treatment was started on the same day of STZ administration with oral gavage of ASE (80 mg/kg body weight) along with drinking water. At the end of the experimental period (45 days), fasting blood glucose was measured by blood strips using an Accu-Chick Performa device (Germany). Furthermore; histopathological and immunohistochemical studies were performed. Results: Results showed that ASE significantly decreased blood glucose level and caspase-3 immunoexpression in treated diabetic mice as compared to untreated diabetic ones. Moreover, ASE improved the histopathological pattern to show a less injury. Conclusion: administration of ASE showed significant ameliorative effects on the biochemical, histopathological and immunohistochemical parameters in kidney tissues of treated diabetic mice.

The Ameliorative Potential of Saffron Against the Histological and Immunohistochemical Changes in Kidney of Albino Mice Due to Streptozotocin-Induced Diabetes Mellitus

Background: multiple-organ failure is the chief inducer of death in diabetes mellitus and hyperglycaemiainduced oxidative stress is responsible for serious complications including nephropathy. Medicinal plants with antioxidant activity may ameliorate oxidative status and improve the histological and immunohistochemical lesions resulted in chronic hyperglycemia in diabetes. Aim of the work: this study aimed to assess the beneficial effects of aqueous saffron extract (ASE) in streptozotocin (STZ)-induced diabetic mice by investigating the histopathological and immunohistochemical pattern in kidney tissues of different experimental groups. Material and Methods: fasted mice were intraperitoneally (IP) injected by a single dose of a STZ (60 mg/kg body weight). After 24 hours, animals with fasting blood glucose over than 300 mg/dl were considered diabetic. The experimental groups were; control (1), saffron (2), diabetic (3) and diabetic + saffron (4). The treatment was started on the same day of STZ administration with oral gavage of ASE (80 mg/kg body weight) along with drinking water. At the end of the experimental period (45 days), fasting blood glucose was measured by blood strips using an Accu-Chick Performa device (Germany). Furthermore; histopathological and immunohistochemical studies were performed. Results: Results showed that ASE significantly decreased blood glucose level and caspase-3 immunoexpression in treated diabetic mice as compared to untreated diabetic ones. Moreover, ASE improved the histopathological pattern to show a less injury. Conclusion: administration of ASE showed significant ameliorative effects on the biochemical, histopathological and immunohistochemical parameters in kidney tissues of treated diabetic mice.

Effect of Kaempferol isolated from seeds of Eruca sativa on changes of pain sensitivity in Streptozotocin-induced diabetic neuropathy.

Generation of excessive reactive oxygen species (ROS) and advanced glycation end products (AGEs), and cellular apoptosis are implicated in the pathogenesis of diabetic neuropathy. Present study was aimed to explore the effect of Eruca sativa and Kaempferol (KP) on hyperalgesia (thermal and mechanical); tactile allodynia, motor nerve conduction velocity (MNCV) and oxidative-nitrosative stress in streptozotocin (STZ) induced experimental diabetes. Neuropathy developed in diabetic rats was evident from a marked hyperalgesia and allodynia; reduced MNCV associated with excess formation of AGEs and ROS. Chronic treatment with E. sativa hydroalcoholic extract (EHA; 100, 200 and 400mg/kg) and KP (5 and 10mg/kg) for 30days starting from the 60th day of STZ administration significantly ameliorated behavioral and biochemical changes linked to diabetic neuropathy. Present study suggested that EHA and KP corrected hyperglycemia and reversed the pain response partially in diabetic rats along via modulating oxidative and nitrosative stress along with reduction of AGEs formation in diabetic rats. Thus E. sativa might be beneficial in chronic diabetes, ameliorate the progression of diabetic neuropathy and may also find application in diabetic neuropathic pain.

Evaluation of the Antioxidant and Antiglycation Effects of Lactarius deterrimus and Castanea sativa Extracts on Hepatorenal Injury in Streptozotocin-Induced Diabetic Rats.

The present study aimed to investigate the beneficial effects of the treatment with extracts from the edible mushroom Lactarius deterrimus (Ld) and the chestnut Castanea sativa (Cs), separately and in combination (MIX Ld/Cs), on oxidative stress and advanced glycation end-product (AGE)-mediated hepatorenal injury in a rat model of streptozotocin (STZ)-induced diabetes by examining pathways responsible for maintenance of redox homeostasis. An experimental model of diabetes was induced in rats by the administration of 40 mg/kg STZ intraperitoneally (i.p.) for 5 consecutive days. The examined extracts were applied separately at a dose of 60 mg/kg i.p. and in combination (60 mg/kg each extract; i.p.) for 4 weeks, starting from the last day of STZ administration. The improvement of hepatorenal function in diabetic rats treated with the extracts was associated with an improved glycemic and lipid status and suppression of oxidative stress and thereby oxidative damage of lipids and DNA. Besides the fact that both extracts inhibited protein glycation and AGE formation in vitro, they also reduced non-enzymatic glycosylation in diabetic rats in vivo. The observed antiglycation activity of the examined extracts (separately and in combination) was accompanied with the inhibition of CML-mediated RAGE/NF-κB activation and reduction of enzymatic O-GlcNAcylation in liver and kidney tissues of diabetic rats. Taken together, these results reveal that the administration of chestnut and mushroom extracts, either individually or together, activates a coordinated cytoprotective response against diabetes-induced hepatorenal injury not only through recovery of the antioxidant defense system of the cell, but also through a marked antiglycation activity.

MPGES-2 deletion remarkably enhances liver injury in streptozotocin-treated mice via induction of GLUT2

Microsomal prostaglandin E synthase-2 (mPGES-2) deletion does not influence in vivo PGE2 production and the function of this enzyme remains elusive. The present study was undertaken to investigate the role of mPGES-2 in streptozotocin (STZ)-induced type-1 diabetes and organ injuries. mPGES-2 wild type (WT) and knockout (KO) mice were treated by a single intraperitoneal injection of STZ at the dose of 120 mg/kg to induce type-1 diabetes. Subsequently, glycemic status and organ injuries were evaluated. Following 4 days of STZ administration, mPGES-2 KO mice exhibited severe lethality in contrast to the normal phenotype observed in WT control mice. In a separate experiment, the analysis was performed at day 3 of the STZ treatment in order to avoid lethality. Blood glucose levels were similar between STZ-treated KO and WT mice. However, the livers of KO mice were yellowish with severe global hepatic steatosis, in parallel with markedly elevated liver enzymes and remarkable stomach expansion. However, the morphology of the other organs was largely normal. The STZ-treated KO mice displayed extensive hepatocyte apoptosis compared with WT mice in parallel with markedly enhanced inflammation and oxidative stress. More interestingly, a liver-specific 50% upregulation of GLUT2 was found in the KO mice accompanied with a markedly enhanced STZ accumulation and this induction of GLUT2 was likely to be associated with the insulin/SREBP-1c pathway. Primary cultured hepatocytes of KO mice exhibited an increased sensitivity to STZ-induced injury and higher cellular STZ content, which was markedly blunted by the selective GLUT2 inhibitor phloretin. mPGES-2 deletion enhanced STZ-induced liver toxicity possibly via GLUT2-mediated STZ uptake, independently of diabetes mellitus.

Alpha-lipoic acid upregulates antioxidant enzyme gene expression and enzymatic activity in diabetic rat kidneys through an O-GlcNAc-dependent mechanism

The combined hyperglycemia lowering and antioxidant actions of α-lipoic acid (LA) contribute to its usefulness in preventing renal injury and other diabetic complications. The precise mechanisms by which LA alters diabetic oxidative renal injury are not known. We hypothesized that LA through its hypoglycemic effect lowers O-GlcNAcylation which influences the expression and activities of antioxidant enzymes which assume important roles in preventing diabetes-induced oxidative renal injury. An experimental model of diabetes was induced in rats by the administration of 40mg/kg streptozotocin (STZ) intraperitoneally (i.p.) for five consecutive days. LA was applied at a dose of 10mg/kg i.p. for 4weeks, starting from the last day of STZ administration. An improved glycemic status of LA-treated diabetic rats was accompanied by a significant suppression of oxidative stress and a reduction of oxidative damage of lipids, proteins and DNA. LA treatment normalized CuZn-superoxide dismutase (SOD) and catalase activities in renal tissue of diabetic rats. These changes were allied with upregulated gene expression and lower levels of O-GlcNA glycosylation. The accompanying increase in MnSOD activity was only linked with upregulated gene expression. The observed antioxidant enzyme gene regulation was accompanied by nuclear translocation of Nuclear factor-erythroid-2-related factor 2 (Nrf2), enhanced expression of heat shock proteins (HSPs) and by reduction in O-GlcNAcylation of HSP90, HSP70, and extracellular regulated kinase and p38. α-Lipoic acid administration activates a coordinated cytoprotective response against diabetes-induced oxidative injury in kidney tissue through an O-GlcNAc-dependent mechanism.

Alpha-lipoic acid preserves the structural and functional integrity of red blood cells by adjusting the redox disturbance and decreasing O-GlcNAc modifications of antioxidant enzymes and heat shock proteins in diabetic rats

The aim of this study was to investigate whether the daily administration of α-lipoic acid (LA) during 4 weeks prevents the redox disturbance in red blood cells (RBC) described in diabetes Multiple low-dose streptozotocin (STZ) diabetes was induced in rats by the administration of 40 mg/kg STZ intraperitoneally (i.p.) for 5 consecutive days. LA was applied at a dose of 10 mg/kg i.p. for 4 weeks, starting from the last day of STZ administration. The LA-treated diabetic rats exhibited a general systemic improvement, revealed as the near restoration of body weight and of essential biochemical parameters. The latter was displayed as decreased hyperglycemia, lower triglyceride levels and lower serum activities of alanine aminotransferases and aspartate aminotransferases that point to a general improvement of diabetes-linked organ "lesions". The LA-treated diabetic rats also exhibited significant alleviation of oxidative stress, manifested as decreased lipid peroxidation and lower glycation levels of serum proteins and hemoglobin, while the RBC exhibited increased activities of antioxidant enzymes and elevated levels of reduced glutathione. In RBC, this was accompanied by decreased post-translational glycosylation by O-bound β-N-acetylglucosamine (O-GlcNAc) of the antioxidant enzymes superoxide dismutase and catalase and of heat shock proteins HSP70 and HSP90. LA through its powerful antioxidant activity preserves the structural and functional integrity of RBC in diabetes. The RBC can then assume a more efficient role as the first line of systemic defense against diabetic complications arising from oxidative stress-induced damage of other tissues and organs.

Changes in cardiac heparan sulfate proteoglycan expression and streptozotocin-induced diastolic dysfunction in rats

BackgroundChanges in the proteoglycans glypican and syndecan-4 have been reported in several pathological conditions, but little is known about their expression in the heart during diabetes. The aim of this study was to investigate in vivo heart function changes and alterations in mRNA expression and protein levels of glypican-1 and syndecan-4 in cardiac and skeletal muscles during streptozotocin (STZ)-induced diabetes.MethodsDiabetes was induced in male Wistar rats by STZ administration. The rats were assigned to one of the following groups: control (sham injection), after 24 hours, 10 days, or 30 days of STZ administration. Echocardiography was performed in the control and STZ 10-day groups. Western and Northern blots were used to quantify protein and mRNA levels in all groups. Immunohistochemistry was performed in the control and 30-day groups to correlate the observed mRNA changes to the protein expression.ResultsIn vivo cardiac functional analysis performed using echocardiography in the 10-day group showed diastolic dysfunction with alterations in the peak velocity of early (E) diastolic filling and isovolumic relaxation time (IVRT) indices. These functional alterations observed in the STZ 10-day group correlated with the concomitant increase in syndecan-4 and glypican-1 protein expression. Cardiac glypican-1 mRNA and skeletal syndecan-4 mRNA and protein levels increased in the STZ 30-day group. On the other hand, the amount of glypican in skeletal muscle was lower than that in the control group. The same results were obtained from immunohistochemistry analysis.ConclusionOur data suggest that membrane proteoglycans participate in the sequence of events triggered by diabetes and inflicted on cardiac and skeletal muscles.

Impact of experimental diabetes and insulin replacement on epididymal secretory products and sperm maturation in albino rats

The present study is aimed to explore the impact of experimental diabetes and insulin replacement on epididymal secretory products, sperm count, motility, and fertilizing ability in albino rats. Prepubertal and adult male Wistar strain rats were made diabetic with a single intraperitoneal injection of streptozotocin (STZ), at 120 and 65 mg/kg body weight for prepubertal and adult rats, respectively. After 3 days of STZ administration, insulin was given to a group of diabetic rats at a dose of 3 U/100 g body weight, subcutaneously and killed after 20 days of treatment. STZ-diabetes significantly reduced the epididymal tissue concentrations of testosterone, androgen-binding protein, sialic acid, glycerylphosphoryl choline, and carnitine, suggesting its adverse effects on the secretory activity and concentrating capacity of epididymal epithelium. Impaired cauda epididymidal sperm motility and fertility (in vivo) of STZ-diabetic rats imply the defective sperm maturation. Insulin replacement prevented these changes either partially or completely. From the above findings, it is evident that STZ-diabetes has an adverse effect on sperm maturation, which may be due to the decrease in the bioavailability of testosterone and epididymal secretory products.

고려홍삼의 당뇨병성 신장병증 개선 효과

자연발생적 고혈압 흰쥐에 STZ로 당뇨를 유발한 고혈압-당뇨 질환모델에서 고려홍삼 조사포닌분획과 비사포닌 분획간의 신장보호 활성을 비교해 보았다. STA 65mg/kg용량을 투여한 후 3일에 네 그룹으로 나누어 본 실험에 임하였다. 신장비대에 대한 저해 활성을 비교해 보았을 때 GTS와 GNS 각각 12, 13% 억제 활성을 나타내었고 두 군간에는 유의적인 차이를 보이지 않았다. 한편 요 중 요소질소의 배설은 GNS 투여군에서는 69% 증가(p＜0.05)한 반면 GTS 투여군은 31%만이 증가하였다. 혈중 포도당, 콩 콜레스테롤 및 중성지방의 경우는 고혈압-당뇨 대조군과 비교시 홍삼투여군 두군 모두에서 유의한 차이를 발견할 수 없었다. 반면 oxidative stress를 저해하는 효소인 SOD 활성에 있어서는 GNS투여군에서 대조군에 비해 17%유의하게 상승하는 활성을 보여주었다. 신장비대의 지표인 TGG-<TEX>$\beta$</TEX>1, fibronectin그리고 upstream의 MEPK인 p-38, ERK 등의 발현을 그룹간 비교해 본 결과 모든 지표에서 비사포닌 분획이 사포닌 분획에 비해 우수한 억제활성을 나타내었다. TGF-<TEX>$\beta$</TEX>1의 mRNA 및 단백질의 발현을 살펴보았을 때 GNS 투여군은 각각 33%, 91% 억제활성을 나타낸 반면 GTS 투여군은 각각 5%, 65% 억제활성을 나타내었다. Fibronectin 단백질의 발현에서도 GNS 투여군은 87% 억제 활성을 나타낸 반면 GTS 투여군은 28% 저해활성을 나타내었다. 본 실험의 결과를 종합해보면 고려홍삼의 신장보호 활성은 사포닌 분획보다는 비사포닌 분획에 함유된 성분에 의해 일어나는 효과가 아닌가 추측된다. The renoprotective effects of Korean Red Ginseng were examined in STZ-induced diabetic spontaneously hypertensive rats (SHR). After 3 day administration of streptozotocin (STZ), animals were divided into four groups : Group 1, hypertensive rats (H); Group 2, hypertensive rats with diabetes (HD); Group 3, hypertensive rats with diabetes administered with 100 mg/kg of ginseng total saponin(GTS); Group 4, hypertensive rats with diabetes administered with 600 mg/kg of ginseng non-saponin (GNS). After 2 weeks oral administraions of GTS and GNS, body weight, kidney weight, plasma glucose, urinary albumin excretion, serum creatinine, urea nitrogen and blood pressure were examined. After 3,7 and 21 day of STZ administration, expressions of TGF-<TEX>${\beta}$</TEX>1 and fibronectin in kidney were analyzed by immunoblotting and/or immunohistochemistry. GTS and GNS treatments slightly decreased blood pressure when compared to H and HD groups. Also, GTS and GNS treatments ameliorated kidney hypertrophy without affecting plasma glucose levels. Meanwhile, GNS treatment increased Cu/Zn-SOD activity in kidney and generally showed more efficient renoprotective effects than GTS. We suggest that the renoprotective effects of ginseng partially result from downregulations of TGF-<TEX>${\beta}$</TEX>1, fibronectin expressions and anti-oxidative activity of ginseng non-saponin.

Centroacinar and intercalated duct cells as potential precursors of pancreatic endocrine cells in rats treated with streptozotocin

The present study examined the possibility for regeneration of pancreatic endocrine cells from centroacinar (CA) and intercalated duct (ICD) cells in rat pancreas after 5 days of continuous streptozotocin (STZ) administration. Nine rats were divided into 3 experimental groups: 1) Control group, 2) Short term recovery group; three days after STZ administration (STZ 3), and 3) Long term recovery group; ten days post-STZ administration (STZ 10). The CA and ICD cells in the STZ 3 group had swollen cytoplasm, and sometimes contained a vesicle within the core. An insulin positive signal was detected in and around the CA and ICD cells. In the STZ 3 group, cytokeratin 20 signals were co-localized with insulin signals in both CA and ICD cells. Electron microscopically, endocrine cells and small pancreatic islets were in close contact with CA and ICD cells. Systemic biophysical serum data reflected these immunohistological results. The present results suggest that CA and ICD cells are involved in the regeneration of pancreatic B cells in rats following a lesion produced by five consecutive days of STZ administration.

Streptozotocin-diabetes impairs prolactin binding to Leydig cells in prepubertal and pubertal rats.

Prolactin (PRL) binding to Leydig cells in prepubertal and pubertal streptozotocin (STZ)-diabetic and insulin-treated rats was studied. Prepubertal (30-day-old) and pubertal (50-day-old) rats were made diabetic by single injection of STZ (120 and 100 mg/kg b.wt, respectively). After 3 days of STZ administration, a group of rats was given insulin injections subcutaneously (3 U/100 g b.wt/day in 2 equally divided doses). Animals of prepubertal and pubertal groups were killed on postnatal days 51 and 71, respectively. Age-dependent increase in serum testosterone, PRL levels and PRL receptors on Leydig cells were prevented by STZ-diabetes. Insulin administration partly or completely prevented these changes. These results suggest that steroidogenic defects in Leydig cells of prepubertal and pubertal diabetic rats may be associated with decrease in serum PRL levels and its receptors on Leydig cells. Insulin probably has a role in the maintenance of PRL receptor numbers on Leydig cells during pubertal maturation.