Heat Shock Protein 70 Immunoreactivity Research Articles

Pancreatic Antioxidative Defense and Heat Shock Proteins Prevent Islet of Langerhans Cell Death After Chronic Oral Exposure to Cadmium LOAEL Dose.

Cadmium, a hazardous environmental contaminant, is associated with metabolic disease development. The dose with the lowest observable adverse effect level (LOAEL) has not been studied, focusing on its effect on the pancreas. We aimed to evaluate the pancreatic redox balance and heat shock protein (HSP) expression in islets of Langerhans of male Wistar rats chronically exposed to Cd LOAEL doses, linked to their survival. Male Wistar rats were separated into control and cadmium groups (drinking water with 32.5 ppm CdCl2). At 2, 3, and 4 months, glucose, insulin, and cadmium were measured in serum; cadmium and insulin were quantified in isolated islets of Langerhans; and redox balance was analyzed in the pancreas. Immunoreactivity analysis of p-HSF1, HSP70, HSP90, caspase 3 and 9, and cell survival was performed. The results showed that cadmium exposure causes a serum increase and accumulation of the metal in the pancreas and islets of Langerhans, hyperglycemia, and hyperinsulinemia, associated with high insulin production. Cd-exposed groups presented high levels of reactive oxygen species and lipid peroxidation. An augment in MT and GSH concentrations with the increased enzymatic activity of the glutathione system, catalase, and superoxide dismutase maintained a favorable redox environment. Additionally, islets of Langerhans showed a high immunoreactivity of HSPs and minimal immunoreactivity to caspase associated with a high survival rate of Langerhans islet cells. In conclusion, antioxidative and HSP pancreatic defense avoids cell death associated with Cd accumulation in chronic conditions; however, this could provoke oversynthesis and insulin release, which is a sign of insulin resistance.

Histological evaluation of the effects of rapamycin and 3-methyladenine on cisplatin-induced epididymal injury in rats

Purpose: In this study, we aimed to determine the effects of autophagy inhibitor and activator on Cisplatin (Cis)-induced tissue damage. 
 Materials and Methods: A total of 24 male Wistar albino rats were divided into 4 groups including 6 rats per group in this study. Groups are as follows; Control, Cisplatin (Cis) (8 mg/kg), Rapamycin (Rapa) (2 mg/kg), 3-methyladenine (3-MA) (15 mg/kg). Rapa and 3-MA were given intraperitoneally for 15 days. Cis was administered as a single dose on the 7th day of the experimental period. At the end of the experimental procedure, epididymis tissues were extracted. Hematoxylin and eosin staining and Heat shock protein-70 (HSP70) immunohistochemistry were applied to the sections taken after histological techniques. 
 Results: Dispersion in the tubule basement membrane and vacuolization in the tubule was observed in the Cis group. It was also observed that some epithelial cells were more eosinophilic in the Cis group. Tissue sections of Rapa and 3-MA had a more regular appearance in terms of epithelization and tubule basement membrane. HSP70 immunoreactivity was observed in the intertubuler connective tissue of all groups. 
 Conclusion: The epididymis was affected by agents such as Cis in terms of the protection of semen quality and potency of spermatozoa. Rapa may be more effective than 3-MA in the epididymis against Cis toxicity.

Role of Heat Shock Protein 70 Expression in Identification of Death Due to Fatal Thermal Exposure

Heat shock proteins (HSPs), are a group of proteins that function as intra-cellular chaperones for other proteins. They are expressed by cells in response to exposure to stress conditions. The aim of the present study was to evaluate the role of heat shock protein 70 (HSP70) expression as vitality marker in identification death due to fatal thermal exposure (fire). This study was carried out on 21 cases of fire related fatalities (group I), 21 cases of acute traumatic death without any evidence of antemortem thermal exposure (group II). All autopsy cases of group I were examined regarding the degree of burn, carbon soot aspiration and survival time. Carboxy hemoglobin (COHb) blood level was assessed. Immunohistochemical examination of lungs, kidneys, heart and liver in all cases of both groups was done. Cases of group I showed significant strong positive HSP70 immunoreactivity (grade 3) in the lung and kidney sections either with short or long survival time exposure when compared with cases of group II. Sections from heart and liver in both groups showed weak HSP70 immunoreactivity. There was no association between the degree of HSP70 expression and degree of burn, presence or absence of carbon soot and COHb concentration in blood in group I. It was concluded that the immunohistochemical investigation of HSP 70 expression in lungs and kidneys can support the proof of vitality in death due to fatal thermal exposure.

Heat shock protein 70 increases cell proliferation, neuroblast differentiation, and the phosphorylation of CREB in the hippocampus

In the present study, we investigated the effects of heat shock protein 70 (HSP70) on novel object recognition, cell proliferation, and neuroblast differentiation in the hippocampus. To facilitate penetration into the blood–brain barrier and neuronal plasma membrane, we created a Tat-HSP70 fusion protein. Eight-week-old mice received intraperitoneal injections of vehicle (10% glycerol), control-HSP70, or Tat-HSP70 protein once a day for 21 days. To elucidate the delivery efficiency of HSP70 into the hippocampus, western blot analysis for polyhistidine was conducted. Polyhistidine protein levels were significantly increased in control-HSP70- and Tat-HSP70-treated groups compared to the control or vehicle-treated group. However, polyhistidine protein levels were significantly higher in the Tat-HSP70-treated group compared to that in the control-HSP70-treated group. In addition, immunohistochemical study for HSP70 showed direct evidences for induction of HSP70 immunoreactivity in the control-HSP70- and Tat-HSP70-treated groups. Administration of Tat-HSP70 increased the novel object recognition memory compared to untreated mice or mice treated with the vehicle. In addition, the administration of Tat-HSP70 significantly increased the populations of proliferating cells and differentiated neuroblasts in the dentate gyrus compared to those in the control or vehicle-treated group based on the Ki67 and doublecortin (DCX) immunostaining. Furthermore, the phosphorylation of cAMP response element-binding protein (pCREB) was significantly enhanced in the dentate gyrus of the Tat-HSP70-treated group compared to that in the control or vehicle-treated group. Western blot study also demonstrated the increases of DCX and pCREB protein levels in the Tat-HSP70-treated group compared to that in the control or vehicle-treated group. In contrast, administration of control-HSP70 moderately increased the novel object recognition memory, cell proliferation, and neuroblast differentiation in the dentate gyrus compared to that in the control or vehicle-treated group. These results suggest that Tat-HSP70 promoted hippocampal functions by increasing the pCREB in the hippocampus.

Natural Infection with Rabies Virus: A Histopathological and Immunohistochemical Study of Human Brains

ObjectivesDespite all the efforts and increased knowledge of rabies, the exact mechanisms of infection and mortality from the rabies virus are not well understood. To understand the mechanisms underlying the pathogenicity of rabies virus infection, it is crucial to study the tissue that the rabies virus naturally infects in humans.MethodsCerebellum brain tissue from 9 human post mortem cases from Iran, who had been infected with rabies virus, were examined histopathologically and immunohistochemically to evaluate the innate immune responses against the rabies virus.ResultsHistopathological examination revealed inflammation of the infected cerebellum and immunohistochemical analyses showed an increased immunoreactivity of heat shock protein 70, interleukin-6, interleukin-1, tumor necrosis factor-alpha, caspase-3, caspase-9, toll-like receptor3 and toll-like receptor4 in the infected brain tissue.ConclusionThese results indicated the involvement of innate immunity in rabies infected human brain tissue, which may aggravate the progression of this deadly disease.

Effects of MDMA (ecstasy) on apoptosis and heat shock protein (HSP70) expression in adult rat testis

Background: This study was conducted to investigate the effects of MDMA (3,4-methylenedioxymethamphetamine, ecstasy) on apoptosis and heat shock protein expression in adult rat testis.Methods: Twenty male rats were divided into four groups, two experimental groups (1 and 2), sham control and control. For 16 consecutive days, the experimental groups 1 and 2 were received 5 and 10 mg/kg intraperitoneal (ip) injection of ecstasy, respectively, and in the sham control group, the only saline was injected. In the control group there was no intervention. Finally, the rat's testes were removed and processed for terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and immunohistochemical techniques.Results: Both doses of MDMA in experimental groups 1 and 2 significantly increased the mean number of TUNEL-positive cells in the germinal epithelium and Leydig cells (p < 0.05). Also in the experimental groups, the immunoreactivity of heat shock protein 70 (HSP70) significantly increased in the testis (p < 0.05).Conclusions: The findings revealed that MDMA administration increases the level of immunoreactivity of HSP70 and TUNEL-positive cells in the testicular tissue.

Molecular cloning, expression pattern, and chemical analysis of heat shock protein 70 (HSP70) in the mudskipper Boleophthalmus pectinirostris: Evidence for its role in regulating spermatogenesis

Heat shock protein 70 (HSP70) is molecular chaperone that is important for reproductive biological processes. In this study, a full length HSP70 from the mudskipper (Boleophthalmus pectinirostris) was characterized. It was found to contain: a 108bp 5′-untranslated region, a 208bp 3′-untranslated region, and a 1953bp open reading frame, which encodes a protein of 650 amino acids with a theoretical molecular weight of 71.1kDa and an isoelectric point of 5.17. RT-PCR analysis revealed that HSP70 was ubiquitously expressed in all major tissues with differential expression levels. This suggests that HSP70 has vital and conserved biological functions. HSP70 was localized mainly in the cytoplasm of germinal cells, indicating an important role of this protein during spermatogenesis. In response to heat stress, the testes presented abnormal morphology in connective tissues, in which HSP70 immunoreactivity was not observed. HSP70 mRNA expression in the gill, liver, and testes was significantly increased, which suggests that HSP70 plays an important role in protection against heat stress.

Histological and immunohistochemical study of the role of glutamine on lipopolysaccharide-induced pancreatitis and associated lung injury

Background Lipopolysaccharide (LPS) is an important factor in the incidence of sepsis. Sepsis is associated with acute pancreatitis, which might be complicated by multiorgan dysfunction, among which is the lung. Glutamine (GLN) is an essential amino acid that plays a significant role in cell homeostasis and organ metabolism. The aim of this study was to investigate the possible protective role of GLN against LPS-induced pancreatitis and the associated lung injury. Materials and methods Twenty-four male albino rats were divided into three groups (n=8 each). The first group served as the control group; the second received an intravenous injection of 5 mg/kg LPS; and the third group was given an intraperitoneal dose of 0.75 g/kg of l-GLN with LPS. After 6 h, the pancreas and lungs were dissected, processed, sectioned, and stained with H&E and with an immunohistochemical stain for heat shock protein 70 (HSP70). Area percentage of HSP70-positive immunoreactivity was measured, followed by statistical analysis. Results The LPS group demonstrated mononuclear cellular infiltration of mostly neutrophils within the connective tissue septa of the pancreas. This was not detected in the group treated with GLN. HSP70-positive immunoreactivity was detected in the apical part of pancreatic acinar cells in the LPS group, which was significantly increased in the GLN-treated group. The lungs of the LPS group showed thickened interalveolar septa with massive inflammatory cellular infiltration. This was diminished in the GLN-treated group. Positive HSP70 immunoreactivity was detected in type II pneumocytes and in the inflammatory cells within the interalveolar septa. This finding was more abundant in the GLN-treated group. Conclusion LPS induced an inflammatory process associated with an increase in HSP70 immunoexpression in both the pancreas and the lung, a finding that was markedly increased in GLN-treated animals. This denotes that GLN might play an anti-inflammatory role by elevating HSP70 expression.

Developmental immunolocalization of heat shock protein 70 (HSP70) in epithelial cell of rat kidney.

During renal development the cells in the medulla are exposed to elevated and variable interstitial osmolality. Heat shock protein 70 (HSP70) is a major molecular chaperone and plays an important role in the protection of cells in the renal medulla from high osmolality. The purpose of this study was to establish the time of immunolocalization and distribution of HSP70 in developing and adult rat kidney. In addition, changes in HSP70 immunolocalization following the infusion of furosemide were investigated. In adult animals, the HSP70 was expressed in the medullary thin ascending limb of Henle's loop (ATL) and inner medullary collecting duct (IMCD). In developing kidney, HSP70 immunoreactivity was first detected in the IMCD of the papillary tip on postnatal day 1. From four to 14 days of age, HSP70 was detected in the ATL after transformation from thick ascending limb, beginning at the papillary tip and ascending to the border between the outer and inner medulla. The immunolocalization of HSP70 in both the ATL and IMCD gradually increased during two weeks. The gradual increase in HSP70 was associated with an increase in its mRNA abundance. However, furosemide infusion resulted in significantly reduced HSP70 immunolocalization in the IMCD and ATL. These data demonstrated that the expression of HSP70 was closely correlated with changes in interstitial osmolality during the development of the kidney. We suggest that HSP70 protects ATL and IMCD cells in the inner medulla from the stress of high osmolality and may be involved in the transformation of the ATL of the long loop of Henle during renal development.

Expression of heat shock protein70 in oral submucous fibrosis and oral squamous cell carcinoma: An immunohistochemical study

Heat shock proteins are a highly conserved group of protective cellular proteins whose synthesis is increased in response to a variety of environmental or pathophysiological stresses. Heat shock proteins are useful biomarkers for carcinogenesis in tissues and signal the degree of differentiation and the aggressiveness of cancers. Regulation of heat shock protein 70 (HSP70) expression in oral submucous fibrosis is not known much, and the aim of this study was to evaluate HSP70 expression in oral submucous fibrosis and oral squamous cell carcinoma by immunohistochemical method and to understand the role of HSP70 in tumorigenesis. Immunohistochemical method was used to detect HSP70 expression in normal oral mucosa, oral submucous fibrosis (n=30) and oral squamous cell carcinoma (n=20). HSP70 immunoreactivity was correlated with histological and clinicopathological features. A significant increase in expression of HSP70 was observed (P<0.000) as the tissue progressed from oral submucous fibrosis towards oral squamous cell carcinoma. HSP70 is synthesized upon stress situations arising in cells of all living organisms. Expression of HSP70 indicates that stress plays an important role as a predisposing factor in oral submucous fibrosis and its subsequent progression to oral squamous cell carcinoma.

Cerebrolysin Attenuates Heat Shock Protein (HSP 72 KD) Expression in the Rat Spinal Cord Following Morphine Dependence and Withdrawal: Possible New Therapy for Pain Management

The possibility that pain perception and processing in the CNS results in cellular stress and may influence heat shock protein (HSP) expression was examined in a rat model of morphine dependence and withdrawal. Since activation of pain pathways result in exhaustion of growth factors, we examined the influence of cerebrolysin, a mixture of potent growth factors (BDNF, GDNF, NGF, CNTF etc,) on morphine induced HSP expression. Rats were administered morphine (10 mg/kg, s.c. /day) for 12 days and the spontaneous withdrawal symptoms were developed by cessation of the drug administration on day 13th that were prominent on day 14th and continued up to day 15th (24 to 72 h periods). In a separate group of rats, cerebrolysin was infused intravenously (5 ml/kg) once daily from day one until day 15th. In these animals, morphine dependence and withdrawal along with HSP immunoreactivity was examined using standard protocol. In untreated group mild HSP immunoreaction was observed during morphine tolerance, whereas massive upregulation of HSP was seen in CNS during withdrawal phase that correlated well with the withdrawal symptoms and neuronal damage. Pretreatment with cerebrolysin did not affect morphine tolerance but reduced the HSP expression during this phase. Furthermore, cerebrolysin reduced the withdrawal symptoms on day 14th to 15th. Taken together these observations suggest that cellular stress plays an important role in morphine induced pain pathology and exogenous supplement of growth factors, i.e. cerebrolysin attenuates HSP expression in the CNS and induce neuroprotection. This indicates a new therapeutic role of cerebrolysin in the pathophysiology of drugs of abuse, not reported earlier.

Ozone oxidative preconditioning is mediated by A1adenosine receptors in a rat model of liver ischemia/ reperfusion

The liver is damaged by sustained ischemia in liver transplantation, and the reperfusion after ischemia results in further functional impairment. Ozone oxidative preconditioning (OzoneOP) protected the liver against ischemia/reperfusion (I/R) injury. The aim of this study was to investigate the role of A(1) adenosine receptor on the protective actions conferred by OzoneOP in hepatic I/R. By using a specific agonist and antagonist of the A(1) subtype receptor (2-chloro N6 cyclopentyladenosine, CCPA and 8-cyclopentyl-1,3-dipropylxanthine, DPCPX respectively), we studied the role of A(1) receptor in the protective effects of OzoneOP on the liver damage, nitiric oxide (NO) generation, adenosine deaminase activity and preservation of the cellular redox balance. Immunohistochemical analysis of nuclear factor-kappa B (NF-kappaB), tumor necrosis factor alpha (TNF-alpha) and heat shock protein-70 (HSP-70) was performed. OzoneOP prevented and/or ameliorated ischemic damage. CCPA showed a similar effect to OzoneOP + I/R group. A(1)AR antagonist DPCPX blocked the protective effect of OzoneOP. OzoneOP largely reduced the intensity of the p65 expression, diminished TNF-alpha production, and promoted a reduction in HSP-70 immunoreactivity. In summary, OzoneOP exerted protective effects against liver I/R injury through activation of A(1) adenosine receptors (A(1)AR). Adenosine and (.)NO produced by OzoneOP may play a role in the pathways of cellular signalling which promote preservation of the cellular redox balance, mitochondrial function, glutathione pools as well as the regulation of NF-kappaB and HSP-70.

Immunohistochemical assesment of heat shock protein 70 in adenoid tissue

To evaluate the expression of heat shock protein 70 (HSP70) and its relation to histopathologic parameters in adenoid hypertrophy and hyperplasia. In addition, HSP70 expression in adenoid tissue was compared with in adult and childhood. Paraffin-embedded adenoid tissue sections were obtained from 19 childhood and 15 adult patients. Expression of HSP70 was evaluated by immunohistochemical staining using anti-HSP70 monoclonal antibody and correlated with histopathologic parameters. Positive HSP70 expression was observed mainly in the mucosal epithelium, lymphocytes in germinal centers, interfollicular lymphocytes, subepithelial plasma cells and vascular endothelium. HSP70 immunoreactivity in the mucosal epithelium with severe intraepithelial lymphocytic infiltration in childhood patients was higher than in adult patients. Although, the immunoreactivity of HSP70 was detected strongly in whole layer of metaplastic squamous epithelium, it was stained only in basal layers in respiratuary epithelium, Lymphocytes stained with HSP70 in germinal center and interfollicular areas of adenoid tissues was higher in childhood patients than in adults. These data suggest that HSP70 expression may have an important role in pathogenesis of adenoid hyperplasia, especially, in childhood.

Effects of intrathecal bupivacaine in conjunction with hypothermia on neuronal protection against transient spinal cord ischemia in rats

Excitotoxic neuronal injury from ischemia may be reduced by local anesthetics. We investigated the neuroprotective effects of intrathecally administered bupivacaine and hypothermia in a rat model of transient spinal cord ischemia. PE-10 intrathecal catheter-implanted male Sprague-Dawley rats were randomly assigned to one of four groups: normothermia (NT) and hypothermia (HT) groups (given 15 microl of normal saline) and bupivacaine (B) and bupivacaine-hypothermia (BHT) groups (given 15 mul of 0.5% bupivacaine). Transient spinal cord ischemia was induced by inflation of a 2F Fogarty catheter placed in the aortic arch for 12 min. The rectal temperature was maintained at 37.0 +/- 0.5 degrees C for the NT and B groups, and at 34.5 +/- 0.5 degrees C for the HT and BHT groups. Motor and sensory deficit scores were assessed 2 and 24 h after reperfusion. Lumbar spinal cords were harvested for histopathology and immunoreactivity of heat shock protein 70 (HSP70). After reperfusion, the motor and sensory deficit scores of the NT group were significantly higher than those of the HT (P < 0.05) and BHT (P < 0.001) groups. Significant differences were evident in the motor and sensory deficit scores between the HT and BHT groups at 24 h (P < 0.05). Neuronal cell death and immunoreactivity of HSP70 were frequently observed in the NT and BT groups, but not in the HT and BHT groups. These results collectively suggest that intrathecal bupivacaine does not provide neuroprotection during normothermic transient spinal cord ischemia in rats, but enhances the neuroprotective effects of hypothermia.

The Effect of Intrathecal Bupivacaine with Hypothermia on Neuronal Protection against Transient Spinal Cord Ischemia in Rats

Background: Local anesthetics can reduece excitotoxic neuronal injury from ischemia. We investigated neuroprotective effects of intrathecally administered bupivacaine and hypothermia in rat model of transient spinal cord ischemia. Methods: A PE-10 intrathecal catheter was implanted into thirty six male Sprague-Dawley rats through L4-5 interlaminar space. Animals of normothermia (N) and hypothermia (H) groups were administered 15l of normal saline, and 15l of 0.5% bupivacaine for bupivacaine (B) and bupivacaine-hypothermia (BH) groups. Transient spinal cord ischemia was induced by inflation of a 2 F Fogarty catheter placed into aortic arch for 12 minutes. During ischemia, rectal temperature was maintained to 37.0 0.5 for N and B groups, 34.5 0.5 for H and BH groups. Motor and sensory deficit score were assessed 2 and 24 hour after reperfusion. Lumbar spinal cords were harvested for histopathology, and for immunoreactivity of heat shock protein 70 (HSP70). Results: The motor and sensory deficit score of N and B group was significantly higher than H group (P

Experimental cauda equina compression induces HSP70 synthesis in dog.

The heat shock protein 70 (HSP70) is a key component of the stress response induced by various noxious conditions such as heat, oxygen stress, trauma and infection. In present study we have assessed the consequences of the compression of lower lumbar and sacral nerve roots caused by a multiple cauda equina constrictions (MCEC) on HSP70 immunoreactivity (HSP70-IR) in the dog. Our data indicate that constriction of central processes evokes HSP70 up-regulation in the spinal cord (L7, S1-Co3) as well as in the corresponding dorsal root ganglion cells (DRGs) (L7-S1) two days following injury. A limited number of bipolar or triangular HSP-IR neurons were found in the lateral collateral pathway (LCP) as well as in the pericentral region (lamina X) of the spinal cord. In contrast, a high number of HSP70 exhibiting motoneurons with fine processes appeared in the ventral horn (laminae VIII-IX) of lumbosacral segments. Concomitantly, close to them a few lightly HSP70-positive neuronal somata or cell bodies lacking the HSP70-IR occurred. In the DRGs, HSP70 expression was mildly up-regulated in small and medium-sized neurons and in satellite cells. On the contrary, DRGs from intact or sham-operated dogs did not reveal HSP70 specific neuronal staining. In conclusion, we have demonstrated that the MCEC in dogs mimicking the cauda equina syndrome in clinical settings evokes expression of HSP70 synthesis in specific neurons of the lumbo-sacro-coccygeal spinal cord segments and in small and medium sized neurons of corresponding DRGs. This suggests that HSP70 may play an active role in neuroprotective processes partly by maintaining intracellular protein integrity and preventing the neuronal degeneration in this experimental paradigm.

Anticonvulsant Activity of Ginseng on Seizures Induced by Chemical Convulsants

To test the anticonvulsant activity of three preparations of American ginseng: whole root extract, whole leaves/stems extract, and a partially purified extract that concentrates the Rb ginsenosides (Rb extract). One hour after treatment with normal saline, or one of the three ginseng preparations, seizures were induced in adult, male, Sprague-Dawley rats with kainic acid (KA; 10 mg/kg), pilocarpine (300 mg/kg, preceded by methylscopolamine, 1 mg/kg, s.c.), or pentylenetetrazol (PTZ, 50 mg/kg). Time to onset of seizure activity, duration of seizure activity for PTZ, seizure severity, and weight change for KA and pilocarpine were determined for each animal. The brains from animals who had received KA or pilocarpine were examined for severe neuronal stress, by using immunoreactivity for heat-shock protein (HSP)72. The Rb extract had a dose-dependent anticonvulsant effect in all three models of chemically induced seizures: increasing the latency to the seizures; decreasing the seizure score, weight loss, and subsequent neuronal damage after pilocarpine; and shortening the seizure duration and reducing mortality after PTZ. The Rb extract also significantly reduced the effects of KA, including completely blocking behavioral seizures. The root preparation increased the mortality rate after administration of pilocarpine, but had no other significant effects. The leaves/stems preparation, at 120 mg/kg, reduced the weight loss after pilocarpine, but had no other significant effects. Ginseng extract made from either the root or leaves/stems is ineffective against chemically induced seizures. A partial purification of the whole extract that concentrates the Rb1 and Rb3 ginsenosides has significant anticonvulsant properties.

Differential cerebral protein synthesis and heat shock protein 70 expression in the core and penumbra of rat brain after transient focal ischemia.

The purpose of this study was to correlate the cerebral protein synthesis (CPS) reductions in the ischemic core and penumbra with the metabolic stress response indicated by heat shock protein 70 (HSP70) synthesis. Rats were subjected to 90 minutes of temporary focal cerebral ischemia produced by occlusion of the middle cerebral artery, using the endovascular suture model. Regional CPS was qualitatively evaluated, with [(35)S]methionine autoradiography, after reperfusion for 2 to 72 hours. The observed changes were correlated with HSP70 immunoreactivity, as assessed in the same brain sections. The ischemic core in the striatum was characterized by HSP70 expression only in endothelial and/or glial cells, with an absence of expression in neurons. The penumbra was delineated as the cortical middle cerebral artery territory region in which HSP70 was also expressed in metabolically stressed neurons. After 2 hours of reperfusion, CPS was reduced to 30 +/- 16% of the homologous contralateral hemisphere value in the core and to 75 +/- 22% in the penumbra (P < 0.05). This difference was still present at 72 hours, when CPS values were 62 +/- 21% and 98 +/- 29% of the nonischemic contralateral hemisphere values in the core and penumbra, respectively (P < 0.05). Persistent inhibition of CPS in regions in which neuronal HSP70 expression is absent may distinguish core areas of infarction from penumbral regions in which neuronal HSP70 is present, which eventually recover from sublethal metabolic stress during reperfusion after temporary focal ischemia.

Temporal expression of immunoreactivity for heat shock protein 25 (Hsp25) in the rat periodontal ligament following transection of the inferior alveolar nerve

The present study examined the immunohistochemical localization of heat shock protein 25 (Hsp25) during the regeneration of nerve fibers and Schwann cells in the periodontal ligament of the rat lower incisor following transection of the inferior alveolar nerve. In the untreated control group, the periodontal ligament of rat incisor did not contain any Hsp25-immunoreaction. On postoperative day 3 (PO 3d), a small number of Schwann cells with slender cytoplasmic processes exhibited Hsp25-immunoreactivity. From PO 5d to PO 21d, Hsp25-positive nerve fibers and Schwann cells drastically increased in number in the alveolar half of the ligament. Although the axons of some regenerating Ruffini-like endings also showed Hsp25-immunoreactions, the migrated Schwann cells were devoid of Hsp25-immunoreaction. Thereafter, Hsp25-positive structures decreased in number gradually to disappear from the periodontal ligament by PO 56d. This temporal expression of Hsp25 in the periodontal ligament well-reflected the regeneration process of the nerve fibers. Hsp25 in the regenerating nerve fibers and denervated Schwann cells most likely serves in modulating actin dynamics and as a cellular inhibitor of apoptosis, respectively.

Trophoblastic Oxidative Stress in Relation to Temporal and Regional Differences in Maternal Placental Blood Flow in Normal and Abnormal Early Pregnancies

Onset of the maternal-placental circulation was studied by Doppler ultrasonography in 65 pairs of age-matched normal and abnormal pregnancies. In normal pregnancies intervillous blood flow increased with gestational age, being detected in 9 of 25 cases at 8 to 9 weeks but in 18 of 20 at 12 to 13 weeks (P = 0.001). By contrast, in abnormal pregnancies flow was detected in nearly all cases (22 of 25) at 8 to 9 weeks (P < 0.001). In addition, regional differences were observed between the groups. Early flow was restricted to the peripheral regions of most normal placentas (P < 0.001), whereas in missed miscarriages it was most common in central regions or throughout the placenta (P < 0.05 and P < 0.001, respectively). Immunoreactivity for heat shock protein 70 and nitrotyrosine residues was greater in samples from peripheral than from central regions of normal placentas (P = 0.028 and P = 0.019, respectively), and from missed miscarriages compared to controls (P = 0.005 and P = 0.001, respectively). Our results indicate that oxidative damage to the trophoblast, induced by premature and widespread onset of the maternal placental circulation secondary to shallow trophoblast invasion, is a key factor in early pregnancy loss. High oxygen concentrations in the periphery of normal early placentas may similarly induce local regression of the villi, leading to formation of the chorion laeve.