Surgical castration performed to reduce male-associated problems results in pain and microbial infections in male animals. Therefore, immunocontraception, which is mediated by the animal's own antibodies against reproductive hormones, has been recommended as an alternative to surgical castration when considering the animal's welfare. In this study, a new immunocontraceptive vaccine composed of six tandem copies of gonadotropin-releasing hormone (GnRH) fused to rat granulocyte-macrophage colony-stimulating factor (GM-CSF) was developed, and its efficacy was evaluated in male rats. Three different doses (10, 50, and 100 μg) of recombinant GM-CSF-GnRH protein were injected three times at intervals of two weeks into male rats. The rats vaccinated with three doses of GM-CSF-GnRH produced a significantly higher level of antibodies against GnRH than that in the negative control rats. Severe atrophy of gonads was observed in rats vaccinated with three doses of GM-CSF-GnRH but not in the negative control rats. The results reveal that the new GnRH vaccine conjugated with rat GM-CSF induces efficient immunocontraception in male rats. This formulation of the immunocontraceptive vaccine would be applicable to both domestic and pet male animals.

Histochemical patterns of lectin binding during development of the rat vomeronasal organ (VNO) were studied to determine whether glycoconjugates are differently expressed after birth. Three types of lectins, Dolichos biflorus agglutinin (DBA), wheat germ agglutinin (WGA), and Ulex europaeus agglutinin I (UEA-I), were studied histochemically in the rat VNO at various stages post-birth: postnatal days 1 and 7, the preweaning period (4 weeks after birth), and at sexual maturity (8 weeks after birth). The free border of the vomeronasal sensory epithelium was positive for both WGA and UEA-I in rats of all ages; whereas, VNO receptor cells and supporting cells were positive only for both WGA and UEA-I from 4 weeks after birth. DBA reactivity was detected in the free border but less so in receptor cells and supporting cells. WGA and UEA-I, but not DBA, showed similar patterns in various ages. In the Jacobson's gland, WGA, UEA-I and DBA were detected in some acini from 4 weeks after birth but not at postnatal days 1 or 7. Collectively, reactivity for three lectins, WGA, UEA-I and DBA, increased in receptor cells and gland acini during postnatal development, possibly contributing to the enhanced chemoreception in rats.

The regional distributions and frequencies of argentaffin endocrine cells in gastrointestinal (GI) tract of osteoporotic Sprague-Dawley rat induced by ovariectomy were studied by Masson-Hamperl silver stain. The experimental animals were divided into two groups, one is non-ovariectomized group (Sham) and the other is ovariectomized group (OVX). Samples were collected from each part of GI tract (fundus, pylorus, duodenum, jejunum, ileum, cecum, colon and rectum) at 10th week after ovariectomy or sham operation. Argentaffin cells were detected throughout the entire GI tract with various frequencies regardless of ovariectomy except for the rectum of OVX in which no cells were detected.

To help the interpretation of causes of death, it is critical that the background incidence of factors contributing to death be recorded and archived. Information was gathered from the control groups of 19 rat carcinogenicity studies. All cases of death occurring within the 2-year period were reviewed. Out of 1124 males and 1084 females, 720 male (64.1%) and 689 female (63.6%) decedents were recorded. There was no difference in the probability of survival between two sexes. Analysis of factors contributing to death revealed that 400 males (48.7%) had neoplastic changes, 189 males (23.0%) had non-neoplastic lesions, and 232 males (28.3%) died from unknown causes.

Severe hypertension (greater than 180 mmHg) develops in spontaneously hypertensive rats (SHR) after 12 wk-oldhowever, it is not clear whether what kinds of molecular mechanism leads to altered cardiac performance following developmental stages in SHR. Also, although the effect of calcineurin (Cn) to promote cardiomyocyte hypertrophy in vivo and in vitro is established, its overall necessity as a hypertrophic mediator is currently an area of ongoing debate. Thus, we have examined i) body weight and blood pressure, ii) differences of expression and distribution of signaling molecules such as Cn, protein kinase B/Akt (PKB/Akt), and extracellular signal-regulated kinase (ERK) between SHR and their agematched control Wistar-Kyoto (WKY) rats following developmental stages.

Alcohol abuse and its medical and social consequences are a major health problem in many areas of the world. Korean red ginseng (KRG) has been traditionally used for the treatment of liver disease. This study was conducted to evaluate the hepatoprotective effects of KRG against hepatotoxicity in Sprague-Dawley rats treated with ethanol (EtOH). Administration of EtOH for 20 days induced significant changes in serum biochemical parameters (aspartate aminotransferase, alanine transaminase, and glucose) accompanied by histological changes in the liver tissue. Treatment with KRG prior to administration of EtOH inhibited the EtOH-induced biochemical and histological changes of the liver. In perfused rat livers, administration of EtOH caused an increase in lactate dehydrogenase (LDH) release into the perfusate and activated the pro-apoptotic Bax protein but inhibited the anti-apoptotic Bcl-2 protein. Pretreatment with KRG prior to administration of EtOH decreased the EtOH-induced LDH release and inhibition of Bcl-2 protein. These results suggest that KRG exerts anti-apoptotic effects and alleviated EtOH-induced liver injury in rats.

This research aimed to investigate the time-course effect of epichlorohydrin (ECH) on epididymal histopathology in Sprague-Dawley rats. Twenty-four male rats were randomly assigned to four groups with 6 rats in each group and were administered a single oral dose of ECH (70 mg/kg) or its vehicle. Six animals each were sacrificed on days 0 (control), 1, 2, and 7 after treatment. During the study period, clinical signs, body weights, reproductive organ weights, testicular spermatid count, epididymal sperm count, motility and morphology, and histopathology were examined. No treatment-related effects on body weights and reproductive organ weights were noted at any time point. On the contrary, sperm motility decreased slightly on days 1 and 2 after treatment and then decreased significantly on day 7 after treatment. The first signs of histological changes were the appearance of cell debris in the ducts and vacuolization of the epithelial cells observed in the proximal caput epididymis on day 1 after treatment. The incidences and grades of the histological changes including cell debris in the ducts, epithelial vacuolization, oligospermia, and epithelial disruption increased on day 2 and then decreased slightly on day 7 after treatment. These results show that a single oral dose of 70 mg/kg ECH to male rats results in cell debris in the ducts and vacuolization of the epithelial cells in the proximal caput epididymis, followed by reversible oligospermia, epithelial disruption, and decreased sperm motility.