Sun-Pil Kim

Melatonin attenuates doxorubicin-induced testicular toxicity in rats.

This study investigated the protective effects of melatonin (MLT) against doxorubicin (DXR)‐induced testicular toxicity and oxidative stress in rats. DXR was given as a single intraperitoneal dose of 10 mg kg−1 body weight to male rats at 1 h after MLT treatment on day 6 of the study. MLT at 15 mg kg−1 body weight was administered daily by gavage for 5 days before DXR treatment followed by an additional dose for 5 days. Sperm analysis, histopathological examination and biochemical methods were used for this investigation. DXR caused a decrease in the weight of seminal vesicles, epididymal sperm count and motility and an increase in the incidence of histopathological changes of the testis. In addition, an increased malondialdehyde (MDA) concentration and decreased glutathione content, glutathione reductase (GR), glutathione‐S‐transferase (GST), superoxide dismutase (SOD) and catalase activities were observed. On the contrary, MLT treatment significantly ameliorated DXR‐induced testicular toxicity in rats. Moreover, MDA concentration and GR, GST and SOD activities were not affected when MLT was administered in conjunction with DXR. These results indicate that MLT had a protective effect against DXR‐induced testicular toxicity and that the protective effects of MLT may be due to both the inhibition of lipid peroxidation and increased antioxidant activity.

Protection of spermatogenesis against gamma ray-induced damage by granulocyte colony-stimulating factor in mice.

The radioprotective effects of granulocyte colony‐stimulating factor (GCSF) were further investigated with respect to the testicular system. Recombinant human GCSF (100 μg kg−1 body weight/day) was administrated to male C3H/HeN mice by subcutaneous injection for three consecutive days before pelvic irradiation (5 Gy) and histopathological parameters were assessed at 12 h and 21 days post‐irradiation (pi). The GCSF protected the germ cells from radiation induced‐ apoptosis (P < 0.01 vs. irradiated group at 12 h pi). GCSF remarkably attenuated radiation‐induced reduction in testis weight, seminiferous tubular diameter, seminiferous epithelial depth and sperm head count in the testes (P < 0.05 versus irradiated group at 21 days pi). Repopulation index and stem cell survival index of the seminiferous tubules were increased in the GCSF‐treated group when compared with the radiation group (P < 0.01). The frequency of abnormal sperm in the GCSF group was lower than that in the irradiated group at 21 days pi (P < 0.01). The decrease in the sperm count and in sperm liability in the epididymis caused by irradiation was counteracted by GCSF. The present study suggests that GCSF protects from radiation‐induced testicular dysfunction via an anti‐apoptotic effect and recovery of spermatogenesis.

Developmental toxic potential of 1,3-dichloro-2-propanol in Sprague-Dawley rats.

This study investigated the potential adverse effects of 1,3-dichloro-2-propanol (1,3-DCP) on pregnant dams and the embryo-fetal development after maternal exposure on gestational days (GD) 6 through 19 in Sprague-Dawley rats. The test chemical was administered to pregnant rats by gavage at dose levels of 0, 10, 30, and 90mg/kg per day (n=10 for each group). All dams underwent Caesarean sections on GD 20, and their fetuses were examined for morphological abnormalities. Maternal toxicity was noted at 90mg/kg/day. Manifestations of toxicity included clinical signs of illness, lower body weight gain, decreased food intake, and increases in the weight of the adrenal glands and the liver. Developmental toxic effects including decreases in fetal body weight and increases in visceral and skeletal variations also occurred at the highest dose. At 30mg/kg, only a minimal maternal toxicity, including a decrease in maternal food intake and an increase in the liver weight, was observed. No adverse maternal or developmental effects were observed at 10mg/kg/day. These results revealed that a 14-day repeated oral dose of 1,3-DCP was minimally embryotoxic but not teratogenic at a maternal toxic dose (90mg/kg/day), and was not embryotoxic at a minimally maternal toxic dose (30mg/kg/day) in rats. Because the developmental toxicity of 1,3-DCP was observed only in the presence of maternal toxicity, it is concluded that the developmental findings observed in the present study are secondary effects to maternal toxicity. Under these experimental conditions, the no-observed-adverse-effect level of 1,3-DCP is considered to be 10mg/kg/day for dams and 30mg/kg/day for embryo-fetal development.

Melatonin prevents gentamicin-induced testicular toxicity and oxidative stress in rats

This study investigated the protective effects of melatonin (MT) against gentamicin (GM)‐induced testicular toxicity and oxidative damage in rats. GM (100 mg kg−1) was injected intraperitoneally (i.p.) to rats for 6 days. MT (15 mg kg−1) was administered i.p. to rats for 6 days at 1 hr after the GM treatment. GM caused a decrease in prostate and seminal vesicle weights, sperm count and sperm motility. Histopathological examination showed various morphological alterations in the testis, characterised by degeneration of spermatogonia/spermatocytes, decrease in the number of early spermatogenic cells and vacuolisation. In addition, an increased malondialdehyde concentration and decreased glutathione content and glutathione reductase, catalase and glutathione‐S‐transferase activities were found in the testis. In contrast, MT treatment significantly attenuated the testicular toxicity of GM, including decreased reproductive organ weights, sperm count, and sperm motility and increased histopathological alterations. MT also had an antioxidant benefit by decreasing the lipid peroxidative product malondialdehyde and increasing the level of the antioxidant glutathione and the activities of antioxidant enzymes in the testis. These results indicate that MT prevents testicular toxicity induced by GM in rats, presumably due to its potent antioxidant activity, and its ability to inhibit lipid peroxidation, and restore antioxidant enzyme activity.

Effect of diallyl disulfide on acute gastric mucosal damage induced by alcohol in rats

This study investigated the gastroprotective effects of diallyl disulfide (DADS), a secondary organosulfur compound derived from garlic (Allium sativum L.) on experimental model of ethanol (EtOH)-induced gastric ulcer in rats. The antiulcerogenic activity of DADS was evaluated by gross/histopathological inspection, pro-inflammatory cytokines, and lipid peroxidation with antioxidant enzyme activities in the stomach. DADS (100 mg/kg) was administered by oral gavage 2 h prior to EtOH treatment (5 ml/kg). The animals were killed 1 h after receiving EtOH treatment. Pretreatment with DADS attenuated EtOH-induced gastric mucosal injury, as evidenced by decreased severity of hemorrhagic lesions and gastric ulcer index upon visual inspection. DADS also prevented histopathological alterations and gastric apoptotic changes caused by EtOH. An increase in tumor necrosis factor-α (TNF-α) and inducible nitric oxide synthase was observed in the gastric tissues of EtOH-treated rats that coincided with increased serum TNF-α and interleukin 6 levels. In contrast, DADS effectively suppressed production of pro-inflammatory mediators induced by EtOH. Furthermore, DADS prevented the formation of gastric malondialdehyde and the depletion of reduced glutathione content and restored antioxidant enzyme activities, such as catalase, glutathione peroxidase, and glutathione reductase in the gastric tissues of EtOH-treated rats. These results indicate that DADS prevents gastric mucosal damage induced by acute EtOH administration in rats and that the protective effects of DADS may be due to its potent antioxidant and anti-inflammatory activities.

Apoptotic cell death in rat epididymis following epichlorohydrin treatment

Epichlorohydrin (ECH) is an antifertility agent that acts both as an epididymal toxicant and an agent capable of directly affecting sperm motility. This study identified the time course of apoptotic cell death in rat epididymides after ECH treatment. Rats were administrated with a single oral dose of ECH (50 mg/kg). ECH-induced apoptotic changes were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and its related mechanism was confirmed by Western blot analysis and colorimetric assay. The TUNEL assay showed that the number of apoptotic cells increased at 8 h, reached a maximum level at 12 h, and then decreased progressively. The Western blot analysis demonstrated no significant changes in proapoptotic Bcl-2-associated X (Bax) and anti-apoptotic Bcl-2 expression during the time course of the study. However, phospho-p38 mitogen-activated protein kinase (p-p38 MAPK) and phospho-c-Jun amino-terminal kinase (p-JNK) expression increased at 8–24 h. Caspase-3 and caspase-8 activities also increased at 8–48 h and 12–48 h, respectively, in the same manner as p-p38 MAPK and p-JNK expression. These results indicate that ECH induced apoptotic changes in rat epididymides and that the apoptotic cell death may be related more to the MAPK pathway than to the mitochondrial pathway.

Evaluation of embryo‐fetal development in rats housed in concrete or hwangto cages during pregnancy

BACKGROUND Recently, it was reported that the 4-week exposure of rats to a concrete building environment under cool temperatures (11.7-12.1 degrees C) had adverse effects on the general health parameters. This study examined the potential effects of concrete and hwangto building environments on pregnant dams and embryo-fetal development in Sprague-Dawley rats. METHODS Groups of 10 mated females were exposed to polycarbonate (control), concrete, or hwangto cages from gestational days (GD) 0 to 20 under cool temperatures (11.9-12.5 degrees C). All the females underwent a caesarean section on GD 20, and their fetuses were examined for any morphological abnormalities. RESULTS The temperatures in the cages were similar in all groups but the relative humidity in the concrete and hwangto groups were higher than in the control group. The concentration of volatile organic compounds in the hwangto group during the study period was lower than in the control group. In the concrete group, maternal effects manifested as an increase in the incidence of clinical signs, a lower body weight, and a decrease in the thymus and ovary weights. Developmental effects included increased post-implantation loss and decreased litter size. In contrast, in the hwangto group, there were no exposure-related adverse effects on the maternal and developmental parameters. CONCLUSIONS Overall, the exposure of pregnant rats to a concrete building environment under cool temperatures has adverse effects on the clinical signs, body weight, organ weight, and embryo-fetal development. On the other hand, exposure to a hwangto building environment does not have any adverse effects on pregnant dams or on embryo-fetal development in rats.

Skin photorejuvenation effects of light‐emitting diodes (LEDs): a comparative study of yellow and red LEDs in vitro and in vivo

Red‐coloured light‐emitting diodes (LEDs) can improve skin photorejuvenation and regeneration by increasing cellular metabolic activity.

The old photovoltaic module detecting research

In this paper, we proposed a detection method for the old photovoltaic modules. The lifespan of general photovoltaic module is 20 years and PV modules installed since the 1990s is caused a failure because the PV module is a lifespan. So, way to detect such failure of PV modules is required. The proposed detection method has advantages that is easier and cheaper than the conventional method. To verify the validity of the proposed method, we carry out a computer-aided simulation.

Isolated Step-up DC/DC Converter applied Soft-switching Method

Recently, renewable energy sources are under the spotlight. due to the depletion of fossil fuels and environmental problem for the carbon dioxide. Among them, research on the Photovoltaic System using solar energy systems has been actively conducted. In this paper, we propose boosting the insulated DC/DC converter topologies Applied to soft-switching methods used in photovoltaic PCS. The proposed topology is of a type that combines a series of full-bridge converter and a boost converter, a full bridge converter and applying the insulation and soft switching system, the output voltage boost stage is carried out for the boost control. The proposed circuit validity was verified through the PSIM simulation and 5kW PV PCS Prototype and experiments.