tretinoin and Prostatic-Diseases

Retinoid-mediated signal transduction plays a crucial role in the embryogenesis of various organs. We previously reported the successful induction of anorectal malformations in mice using retinoic acid (RA). Retinoic acid controls the expression of essential target genes for cell differentiation, morphogenesis, and apoptosis through a complicated interaction in which RA receptors form heterodimers with retinoid X receptors. In the present study, we investigated whether the retinoid antagonist, LE135, could prevent the induction of anorectal malformations (ARMs) in mice.. Retinoic acid was intraperitoneally administered as 100 mg/kg of all-trans RA on E9; and then the retinoid antagonist, LE135, was intraperitoneally administered to pregnant ICR strain mice on the eighth gestational day (E8), 1 day before administration of RA (group B) or on E9, simultaneously (group C) with RA administration. All of the embryos were obtained from the uteri on E18. Frozen sections were evaluated for concentric layers around the endodermal epithelium by hematoxylin and eosin staining.. In group A, all of the embryos demonstrated ARM with rectoprostatic urethral fistula, or rectocloacal fistula, and all of the embryos showed the absence of a tail. In group B, 36% of the embryos could be rescued from ARM. However, all of the rescued embryos had a short tail that was shorter than their hind limb. The ARM rescue rates in group B were significantly improved compared to those in group A (P < .01). In group C, 45% of the embryos were rescued from ARM, but all of the rescued embryos had short tail. The ARM rescue rate in group C was significantly improved compared to that in group A (P < .01). However, there was no significant difference in the ARM rescue rate between group B and Group C.. The present study provides evidence that in the hindgut region, RAR selective retinoid antagonist, LE135, could rescue embryos from ARM. However, the disturbance of all-trans RA acid was limited to the caudal region. Further study to establish an appropriate rescue program for ARM in a mouse model might suggest a step toward protection against human ARM in the future.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Anal Canal; Animals; Cloaca; Dibenzazepines; Drug Administration Schedule; Drug Evaluation, Preclinical; Female; Fistula; Gene Expression Regulation, Developmental; Humans; Injections, Intraperitoneal; Male; Mice; Mice, Inbred ICR; Models, Animal; Pregnancy; Prostatic Diseases; Random Allocation; Receptors, Retinoic Acid; Rectal Fistula; Rectum; Species Specificity; Tail; Tretinoin

The effect of beta-retinoic acid (RA) on carcinogen-induced hyperplasia was studied in organ cultures of mouse prostate gland. 3-Methylcholanthrene (MCA), requiring metabolic activation, or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), not requiring activation, were used to induce hyperplastic changes. Treatment of cultures with MCA or MNNG stimulated cell proliferation and caused the alveolar epithelium to become hyperplastic. The development of this hyperplasia was inhibited when RA was added simultaneously with MCA or MNNG. However, RA had no significant effect on cell proliferation in untreated control cultures. Elimination of carcinogen from the hyperplastic cultures after 8 days of treatment did not reverse hyperplasia of the alveolar epithelium. When the withdrawal of MCA or MNNG was followed by treatment of the cultures with RA, hyperplasia was markedly reversed within 96 hours. Thus RA actively inhibited and reversed the effect of MCA and MNNG, two carcinogens that may have different mechanisms of action.

Topics: Animals; Cell Division; Epithelial Cells; Epithelium; Hyperplasia; Male; Methylcholanthrene; Methylnitronitrosoguanidine; Mice; Organ Culture Techniques; Prostate; Prostatic Diseases; Time Factors; Tretinoin; Vitamin A