Riánsares Arriazu

Immunohistochemical Study of Cell Proliferation, Bcl-2, p53, and Caspase-3 Expression on Preneoplastic Changes Induced by Cadmium and Zinc Chloride in the Ventral Rat Prostate

This work was directed to evaluate immunoexpression of markers for apoptosis, resistance to apoptosis, and cell proliferation, as well as estimates of nuclear size in ventral prostate of rats treated with cadmium chloride and cadmium + zinc chloride because a possible protective effect of zinc has been postulated. The following variables were studied: volume fraction (VF) of Bcl-2 immunostaining, percentage of cells immunoreactive to proliferating cell nuclear antigen (LIPCNA) and p53 (LIp53), numerical density of caspase-3 immunoreactive cells (NV caspase-3), and estimates of volume-weighted mean nuclear volume (υV). The LIPCNA and VF of Bcl-2 were significantly increased in the treated animals. The dysplasias (independent of their origin) showed a significant increase of the LIp53, NV caspase-3, and υV in comparison with normal acini from treated and control animals. It can be concluded that cell proliferation is enhanced in long-term cadmium-exposed rats, and exposure to zinc combined with cadmium had no effect on any of the variables studied when comparing with normal acini. The increase of nuclear υV could indicate a more aggressive behavior for pretumoral lesions.

Expression of Lysophosphatidic Acid Receptor 1 and Relation with Cell Proliferation, Apoptosis, and Angiogenesis on Preneoplastic Changes Induced by Cadmium Chloride in the Rat Ventral Prostate

Background Lysophosphatidic acid (LPA) is a phospholipid growth factor involved in cell proliferation, differentiation, migration, inflammation, angiogenesis, wound healing, cancer invasion, and survival. This study was directed to evaluate the immunoexpression of LPA-1, cell proliferation, apoptosis, and angiogenesis markers in preneoplastic lesions induced with cadmium chloride in rat prostate. Methods The following parameters were calculated in ventral prostate of normal rats and rats that received Cd in drinking water during 24 months: percentages of cells immunoreactive to LPA-1 (LILPA1), PCNA (LIPCNA), MCM7 (LIMCM7), ubiquitin (LIUBI), apoptotic cells (LIAPO), and p53 (LIp53); volume fraction of Bcl-2 (VFBcl-2); and length of microvessels per unit of volume (LVMV/mm3). Data were analyzed using Students t-test and Pearson correlation test. Results The LILPA1 in dysplastic lesions and normal epithelium of Cd-treated rats was significantly higher than those in the control group. Markers of proliferation were significantly increased in dysplastic lesions, whereas some apoptotic markers were significantly decreased. No significant differences between groups were found in VFBcl-2. Dysplastic lesions showed a significant increase of LIp53. The length of microvessels per unit of volume was elevated in dysplastic acini. Statistically significant correlations were found only between LILPA1 and LIUBI. Conclusions Our results suggest that LPA-1 might be implicated in dysplastic lesions induced by cadmium chloride development. More studies are needed to confirm its potential contribution to the disease.

Changes in the number and volume of NPY and VIP neurons from periprostatic accessory vegetative ganglia in pre- and peripubertal rats. A stereological study

The amount of neurons of periprostatic accessory ganglia in pre- and peripubertal rats was studied to ascertain whether the development of these autonomic ganglia is androgen-dependent. Stereological estimates of the volumes and number of neurons immunoreactive to protein gene product 9.5 (PGP 9.5), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) were carried out. Immunostaining of androgen receptors (AR) in the ganglia was also performed. The ganglionic neurons from the two groups studied were immunoreactive to PGP 9.5, NPY, and VIP. Almost all the neurons were immunostained for AR. The ganglionic volume showed a significant increase in peripubertal prostate in comparison with the prepubertal gland. No significant changes were observed with respect to the absolute number of neurons immunoreactive to all the antigens. The neuronal volume was significantly increased in peripubertal rats in comparison with prepubertal animals. These findings led us to the following conclusions: There is no evidence of neurogenesis during pubertal development in the periprostatic accessory ganglia of the rat. The increase of ganglionic volume in puberty is due to the growth in neuronal volume. There were no differences between the sizes of NPY and VIP neurons in pubertal periprostatic accessory ganglia. The development of periprostatic vegetative neurons is androgen-dependent.

Stereological Estimate of the Length of Microvessels and the Number, Proliferation and Apoptosis of Endothelial Cells in Prostate Cancer

Abnormal angiogenesis is a critical feature of many diseases, including cancers and their precursors. Although the association between prostate carcinogenesis and changes in microvascular architecture is well known, these changes are not well-documented from a quantitative point of view. The present work deals with stereological estimates of the number of quiescent and proliferative endothelial cells, and microvessel length in normal and prostate cancer tissues. Un- biased stereological measurements of numerical densities of proliferating cell nuclear antigen immunostained cells, non- proliferating endothelial cells, caspase 3 immunoreactive endothelial cells, and relative length (length density) of mi- crovessels, were performed in control and cancer specimens. There were no changes in either proliferation or apoptosis in carcinoma endothelial cells. A decrease of endothelial cell density, together with an increase of microvessel length den- sity, were detected in prostate cancer specimens. Therefore, the following conclusions can be drawn: a) The increase of angiogenetic activity in prostate carcinogenesis leads to an increment of the microvascular length; b) The amount of endothelial cells per vascular length decreases in prostate cancer; c) There is no decrease of endothelial apoptosis in cancer microvessels. d) The increase of the length den- sity of microvessels in prostate cancer is not directly associated to an enhancement of the endothelial proliferation; and e) The blood supply of epithelium was similar in both cancerous and normal prostate.

Cadmium and Zinc Chloride-induced Preneoplastic Changes in the Rat Ventral Prostate: An Immunohistochemical and Molecular Study

Cadmium chloride (Cd) is a toxicant that has been implicated in human prostate cancer (PCA). The goal of the present study was to evaluate the immunoexpression of markers for cell proliferation, apoptosis, resistance to apoptosis, and to determine mutations on segments of the bcl-2 gene, in preneoplastic lesions induced in rat prostate after treatment with Cd alone or in combination with zinc chloride (Zn). We evaluated: 1) The % of cells positively immunostained for the proliferating cell nuclear antigen (PCNA), 2) The % of apoptotic cells (evaluated by TUNEL), 3) The volume fraction of Bcl-2 immunostaining. 4) The mutations on a segment of 253 pb of bcl-2, in the ventral prostate lobe of normal and treated rats with Cd alone or in the presence of Zn in the drinking water for 18 mo. Our results indicate that the % of PCNA positive nuclei was significantly increased in preneoplastic prostatic acini of Cd-treated rats alone and in combination with Zn, compared to the normal acini of untreated animals. No significant changes were detected on the apoptotic rate or the volume fraction of Bcl-2. Moreover, no significant changes in the band pattern of the amplified segment of bcl-2 gene were observed after Cd treatment. In summary, our data indicate that, prostate dysplasia induced in rats by Cd increases proliferative activity, without significant changes in either apoptosis or bcl-2 immunoreactivity.

Evaluation of PCNA, Caspase 3 and E-cadherin on the Ventral Prostate of Soy Treated Rats

The incidence of certain cancers, including prostate cancer, is considerably higher in western countries than in Southeast Asia. Many studies have linked soy consumption to the lower incidence of prostate cancer in these countries. Twenty male Sprague-Dawley rats were randomized and divided into a control group and a group treated with soy. The ventral prostates of each animal were sectioned and stained with hematoxilin-eosin for morphological description and immunostained to detect PCNA, cleaved caspase 3 and E-cadherin immunoreactivities. Estimates of the number of total epithelial cells and the number of epithelial cells immunoreactive to PCNA and cleaved caspase 3 were calculated using the optical disector technique. Measurement of E-cadherin was carried out by calculating the volume fraction of epithe- lium immunostained by E-cadherin. Soy treated group showed atrophy in the epithelium and a diminished expression of PCNA, cleaved caspase 3 and E-cadherin, which means there is a reduced cell proliferation, apoptosis through caspases way and cell adherence. It can be concluded that soy treatment induces atrophy in the epithelium by reducing cell prolif- eration.