Connexin43 and Angiotensin II Alterations in Hearts of Rats Having Undergone an Acute Exposure to Alcohol

Inhibition of NADPH oxidase by apocynin promotes myocardial antioxidant response and prevents isoproterenol-induced myocardial oxidative stress in rats

Preventive and/or therapeutic interventions for ischemic heart disease have gained considerable attention worldwide. We investigated the mechanism(s) underlying cardioprotection of apocynin (APO) and whether it attenuates isoproterenol (ISO)-induced myocardial damage in vivo. Thirty-two male Wistar Albino rats were randomised into four groups (n = 8 for each group): Group I (Control); Group II (ISO), ISO was given intraperitoneally (ip) (150 mg/kg/d) daily for 2 consecutive days; Group III (APO + ISO), APO was applied ip 20 mg/kg 30 min before the first ISO administration and continued for the next 2 d after the second ISO administration; Group IV (ISO + APO), after the ISO treatment on days 1 and 2, 20 mg/kg APO was given ip on days 3 and 4. Cardioprotective effects of APO were evaluated by biochemical values, histopathological observations and the antiapoptotic relative proteins. Mean blood pressure, heart rate, and electrocardiography (ECG) were also monitored. Malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), total oxidant status (TOS), total antioxidant capacity (TAC), oxidative stress index (OSI), caspase-3 and connexin 43 levels were determined. Major ECG changes were observed in the ISO-treated rats. MDA, TOS, OSI and creatine kinase levels decreased and SOD, CAT, GSH and TAC levels increased, indicating that APO reduced cardiac injury and oxidative stress compared with controls. APO also decreased the number of cardiomyocytes with pyknotic nuclei, inflammatory cell infiltration, intracytoplasmic vacuolisation and myofibrils. APO provides preventive and therapeutic effects on ISO-induced myocardial injury in rats by inhibiting reactive oxygen species production, blocking inflammation and enhancing antioxidant status.

Alterations of Ca(v)1.2 and 5-hydroxytryptamine in rat hearts after positional asphyxia

We investigated alterations of cardiac Ca(v)1.2 and 5-hydroxytryptamine (5-HT) associated with positional asphyxia. Male rats were divided into five groups: a control group with no restraint, group 1 restrained for 1 h, group 2 restrained for 2 h, group 3 restrained for 4 h, and group 4 restrained for 8 h. The rats that were restrained for 8 h ultimately suffered fatal asphyxia. After the restraint periods, the rats were sacrificed and immunohistochemistry was performed to evaluate the expressions of Ca(v)1.2 and 5-HT in the heart. Sections were analyzed by digital image analysis. Cardiac expression of Ca(v)1.2 and 5-HT proteins were significantly decreased by positional asphyxia in the rat, shown by integrated optical density (IOD) compared to controls. Our findings indicate that Ca(v)1.2 and 5-HT alterations could cause abnormal cardiac function, and the proteins investigated here may be useful for investigating the mechanisms underlying positional asphyxia.

Animal experimentation in forensic sciences: How far have we come?

In the third millennium where ethical, ethological and cultural evolution seem to be leading more and more towards an inter-species society, the issue of animal experimentation is a moral dilemma. Speaking from a self-interested human perspective, avoiding all animal testing where human disease and therapy are concerned may be very difficult or even impossible; such testing may not be so easily justifiable when suffering-or killing-of non human animals is inflicted for forensic research. In order to verify how forensic scientists are evolving in this ethical issue, we undertook a systematic review of the current literature. We investigated the frequency of animal experimentation in forensic studies in the past 15 years and trends in publication in the main forensic science journals. Types of species, lesions inflicted, manner of sedation or anesthesia and euthanasia were examined in a total of 404 articles reviewed, among which 279 (69.1%) concerned studies involving animals sacrificed exclusively for the sake of the experiment. Killing still frequently includes painful methods such as blunt trauma, electrocution, mechanical asphyxia, hypothermia, and even exsanguination; of all these animals, apparently only 60.8% were anesthetized. The most recent call for a severe reduction if not a total halt to the use of animals in forensic sciences was made by Bernard Knight in 1992. In fact the principle of reduction and replacement, frequently respected in clinical research, must be considered the basis for forensic science research needing animals.

Changes in FABP1 and gastrin receptor expression in the testes of rats that have undergone electrical injury

Testicular trauma may occur due to accidental electrical injury. The aim of this study was to investigate alterations in the levels of fatty acid-binding protein 1 (FABP1) and gastrin receptor (gastrin R) in the testes following electrical injury. Sprague-Dawley rats were divided into control, fatal electrocution (220 V, 50 Hz, 60 sec) and electrical injury (220 V, 50 Hz, 60 sec) groups (n=8 per group). The animals in the fatal electrocution and electrical injury groups were deeply anesthetized with sodium pentobarbital prior to each treatment, in which the current was delivered via an anode connected to the left foreleg and a cathode to the right hindleg. The rats that survived were subsequently sacrificed by cervical dislocation. Control animals received cervical dislocation alone. Immunohistochemical analysis was performed to evaluate the protein expression of FABP1 and gastrin R in the testes. Sections were evaluated by digital image analysis. The expression levels of FABP1 and gastrin R were significantly increased following electrical injury, supported by an increase in the integrated optical density (IOD) when compared with that in the control group (P<0.05). However, no significant difference was found in FABP1 and gastrin R expression levels between the fatal electrocution and control groups. In summary, the protein expression levels of FABP1 and gastrin R were found to be significantly altered by electrical injury, suggesting that these two proteins may be important in underlying mechanisms of testicular injury during electrical injury. The findings indicate that such alterations would be reflected in abnormal testicular function.

Reduced connexin 43 immunolabeling in the orbitofrontal cortex in alcohol dependence and depression

Reduced density of glial cells and low levels of some astrocyte proteins have been described in the orbitofrontal cortex (OFC) in depression and alcoholism, two disorders often comorbid. These regressive changes may also involve the communication between astrocytes via gap junctions and hemichannels, which play important regulatory roles in neurotransmission. We determined levels and morphological immunostaining parameters of connexin 43 (Cx43), the main protein subunit of astrocyte gap junctions/hemichannels, in the OFC of subjects with depression, alcoholism or comorbid depression/alcoholism as compared to non-psychiatric subjects. Postmortem brain samples from 23 subjects with major depressive disorder (MDD), 16 with alcohol dependence, 13 with comorbid MDD and alcohol dependence, and 20 psychiatrically-normal comparison subjects were processed for western blots to determine Cx43 levels. Area fraction of Cx43 immunoreactivity, and density and average size of immunoreactive puncta were measured in histological sections. There was a significant, larger than 60 percent decrease in Cx43 level in the three psychiatric groups as compared to controls. Area fraction of immunoreactivity and immunoreactive punctum size were reduced in all psychiatric groups, but Cx43-immunoreactive puncta density was reduced only in alcohol-dependent subjects. Among psychiatric subjects, no difference in Cx43 levels or immunostaining was found between suicides and non-suicides. The present data suggest that dysfunction of the OFC is accompanied by reduction in the levels of gap junction protein Cx43 in depression and alcoholism, and reduction in density of Cx43 immunoreactive puncta only in alcoholism, pointing to altered gap junction or hemichannel-based communication in the pathophysiology of those disorders.