Chihaya Kakinuma

Lipoteichoic acid induces preterm delivery in mice

The purpose of this study was to determine whether or not lipoteichoic acid (LTA) could induce preterm delivery in mice. On days 15 and 17 of pregnancy, female C3H/HeN mice impregnated by male B6D2F1 mice were given intraperitoneal injections of LTA (12.5-75 mg/kg, single dose or repeated doses at a 3-h interval). We examined the changes in cervix, placental trophoblasts, and plasma and amniotic fluid concentrations of interleukin-1alpha (IL-1alpha), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) after dosing with LTA. In addition, the effect of LTA on the contraction of isolated uterine muscle from pregnant mice was also measured. The incidence of preterm delivery was highest (100%), when the pregnant animals were treated with 75 mg/kg LTA twice on day 15 of pregnancy or with 25 mg/kg LTA twice on day 17 of pregnancy. LTA-accelerated cervical ripening and placental abruption preceding the onset of preterm delivery, as well as increased plasma and amniotic fluid concentrations of IL-1alpha, IL-6, and TNF-alpha. Also, LTA increased contraction of uterine muscle strips. In conclusion, LTA induced preterm delivery in mice in the same manner as lipopolysaccharide (LPS), but the effective dose of LTA was larger than that of LPS.

Trophoblastic apoptosis in mice with preterm delivery and its suppression by urinary trypsin inhibitor

Objective To investigate histopathologic changes of the placenta in mice with preterm delivery induced by lipopoly-saccharide and the effect of urinary trypsin inhibitor. Methods Female C3H/HeN mice impregnated by male B6D2F1 mice were treated with lipopolysaccharide (50 μg/kg, intraperitoneally) or lipopolysaccharide plus urinary trypsin inhibitor (25 × 104 U/kg, intraperitoneally). At 3, 6, 9, and 18 hours after the second dose of lipopolysaccharide, and at delivery in the control and urinary trypsin inhibitor-treated groups, the concentrations of interleukin-1α and tumor necrosis factor-α were determined in serum and amniotic fluid. Subsequently, the placentas were examined. In the same manner, we examined mice treated with interleukin-1α (250 μg/kg, subcutaneously) on day 15 of pregnancy and intact mice on days 15 and 18 of pregnancy as well as at delivery. To assess the direct action of cytokines, we cultured placental slices with tumor necrosis factor-α, interleukin-1a, or tumor necrosis factor-α plus urinary trypsin inhibitor and examined them morphologically. Results Control mice were characterized by trophoblastic apoptosis and increased serum levels of tumor necrosis factor-α and interleukin-1α. In contrast, urinary trypsin inhibitor-treated mice showed suppression of apoptosis and lower cytokine levels. Interleukin-1α induced trophoblastic apoptosis and increased the serum level of tumor necrosis factor-α. The in vitro study showed that tumor necrosis factor-α directly induced trophoblastic apoptosis in placental slices. Conclusion We demonstrated that trophoblastic apoptosis occurs in the placentas of a mouse model with preterm delivery induced by lipopolysaccharide. We postulated that apoptosis may lead to placental abruption, and its development may be prevented by treatment with urinary trypsin inhibitor.

Acute Toxicity of an Anti-Fas Antibody in Mice

By histopathologic examination of various organs in 3 normal strains, C3H/HeN, ICR, and DBA/1J, of mice treated intravenously once with anti-Fas antibody (Jo2), we failed to determine any target organ, except the liver, responsible for the acute lethality induced by the Fas/anti-Fas antibody interaction. However, we could show the presence of Fas-mediated apoptosis in other organs aside from the liver and normal mouse strain differences in susceptibility to anti-Fas antibody. Among these strains, C3H/HeN was the most susceptible to the antibody, followed by ICR and DBA/1J. We observed Fas-mediated apoptosis in the liver, spleen, thymus, lymph nodes, Peyers patch, intestine, skin, coagulation glands, ovary, uterus, and vagina in all 3 strains and additionally in the epididymides and seminal vesicles in the DBA/1J strain. We also demonstrated that Fas-mediated apoptosis of small lymphocytes in the mantle zone of splenic lymphatic follicles preceded that of the hepatocytes or thymic cells. Since cellular damage was most severe in the liver among all the apoptotic organs in the 3 mouse strains, liver injury induced by anti-Fas antibody is speculated to play a significant role in the death.

Spontaneous adrenal and hepatic myelolipomas in the common marmoset

Myelolipomas occurring simultaneously in the adrenal and liver were found in a 2.7-yr-old, bred female common marmoset (Callithrix jacchus). The animal bore single adrenal and multiple hepatic myelolipomas. The adrenal myelolipoma consisted of mature adipose cells and focal collections of normal hematopoietic elements and was unencapsulated. In the liver, the myelolipomas, which were partially encapsulated, included a large amount of hematopoietic tissue and adipose cells that resembled normal bone marrow cells in various ways. Additionally, one of the multiple nodules contained several bony spicules with osteoblasts. Furthermore, there were invasive figures of hematopoietic cells, such as myeloblasts, erythroblasts, and megakaryocytes, in the hepatic sinusoids around the lesions. Thus, this case has some unusual morphological characteristics and is the first report, to our knowledge, on multiorganic myelolipomas in common marmosets.

Ability of intrauterine bacterial lipopolysaccharide to cause in situ uterine contractions in pregnant rabbits.

Background. To investigate the ability of bacterial lipopolysaccharide delivered by the intrauterine route to cause uterine contractions in rabbits, and to assess the suppressive effect of urinar trypsin inhibitor on them.

Human Natural Tumor Necrosis Factor α Induces Multiple Endocrine and Hematologic Disorders in Rats

Slc:Wistar male rats treated with human natural tumor necrosis factor α (hn TNF-α, 3 X 105 Japan reference units/kg intravenously) for 3 months showed histologic vacuolation of basophils in the anterior pituitary, hyperplasia of the thyroidal follicular epithelium, and hyperplasia of the testicular interstitial cells. The vacuolated basophils were immunohistochemically shown to be thyrotrophs. In addition, there were decreases in plasma levels of triiodothyronine (T3), thyroxin (T4), and testosterone, and an increase in thyroid-stimulating hormone (TSH). The number of lymphocytes in the marginal zones of lymphoid follicles in spleen and lymph nodes and B-lymphocytes in the peripheral blood decreased. Hyperplasia of hematopoietic cells in the bone marrow and decreases in both leukocytes and erythrocytes in the peripheral blood were prominent. Hyperplasia of bile ductular epithelial cells with periportal mononuclear cell infiltration in the liver and increased cellularity in alveolar walls in the lung were also characteristic. In in vitro studies, hn TNF-α inhibited both proliferation and peroxidase activity of thyroid follicular epithelial cells. These findings demonstrate that hn TNF-α may induce histologic vacuolation of thyrotrophs by causing a decrease in plasma levels of T3 and T4; hyperplasia of the thyroid follicular epithelium, which may be attributed to the increased plasma level of TSH; hyperplasia of testicular interstitial cells, by lowering the plasma level of testosterone; hyperplasia of bile ductular epithelial cells; hyperplasia of hematopoietic cells in bone marrow; and the increase in cellularity in pulmonary alveolar walls. In addition, hn TNF-α may suppress the differentiation of B-lymphocytes.

Growth-stimulating effect of dienogest, a synthetic steroid, on rodent, canine, and primate mammary glands

We observed hyperplasia of the mammary gland in female beagle dogs, but not in female rats and monkeys, in 91-day toxicity studies on dienogest. In order to elucidate a possible mechanism for its development and to account for this species difference, we determined the plasma level of growth hormone (GH) in dogs, rats, and monkeys treated orally with dienogest for 91 days. As a result, dogs with mammary hyperplasia showed a prominent, dose-dependent increase in their GH level; and, contrarily, rats and monkeys without the hyperplasia of this organ failed to show any such increase. These results were supported by evidence from immunohistochemical and morphometric analysis of the pituitary gland. In addition, dienogest and medroxyprogesterone acetate (MPA) stimulated the growth of canine mammary epithelial cells in the presence of estradiol in vitro, but had no effect on rat and human mammary epithelial cells incubated under the same conditions. In conclusion, dienogest with progestational activity caused proliferation of the mammary gland in beagle dogs by increasing the secretion of GH, as do other progestational compounds. This change may be partially dependent on the direct effect of the drug.

Dedifferentiated retroperitoneal liposarcoma spontaneously occurring in an aged SD rat

Liposarcoma is a rare neoplasm in rats and is characterized by the presence of lipoblasts containing multiple cytoplasmic vacuoles. We encountered a rare type of liposarcoma in a male SD (Crj:CD(SD)IGS) rat during a long-term study to gather background data. At necropsy at 105 weeks of age, there was a large amount of fatty tissue covering the mesentery, pancreas, and retroperitoneum; a white nodule in the right kidney; and paleness of the liver. Microscopically, the tumor had a well-differentiated component and dedifferentiated high-grade component. Immunohistochemical and electron microscopic examinations revealed that the pleomorphic tumor cells retained the characteristics of lipoblasts. Distant or disseminated metastasis was also confirmed in various organs. A liposarcoma with these histological features is extremely rare in rats, and this is the first report of a highly metastatic dedifferentiated type of liposarcoma originating from the abdominal fat tissue in a rat.