title: Effects of cyclosporin A on the splenic tissue of rats: a histomorphometric analysis.
abstract: Histological studies demonstrated that long-term cyclosporin A treatment of nonantigenically challenged (untransplanted and unimmunized) Lewis rats markedly reduces the total percentage of splenic white pulp when compared to untreated control spleens (mean = 24 vs 34%, P less than 0.001). Direct measurements of periarteriolar sheaths and marginal zones demonstrated a marked reduction in size of these compartments in cyclosporin A-treated rats compared to untreated controls (P less than 0.001). In addition, there was a striking reduction in cellular density of the periarteriolar sheaths (P less than 0.001) and a minimal reduction in cellular density of the marginal zones (P less than 0.1) in the cyclosporin A-treated group when compared to untreated controls. There was no significant difference in total splenic size between the cyclosporin A-treated and the control groups, as indicated by total cross section measurements (mean = 33.3 vs 35.0, P less than 0.4). Qualitative observations of methyl green-pyroninophilic cells within and surrounding the marginal zones of the cyclosporin A-treated spleens revealed a much greater proportion of large pyroninophilic lymphocytes, which suggests that they are B immunoblasts. We conclude that long-term cyclosporin A treatment depletes splenic periarteriolar sheaths and marginal zones, compartments known to contain primary T lymphocytes, and induces an immunoblastic cell proliferation within the marginal zones and red pulp as well.
authors: Department of Pathology, University of California, San Diego 92103.
authors: O A
authors: OA
authors: Armas
authors: R W
authors: RW
authors: Astarita
authors: P L
authors: PL
authors: Wolf
authors: A R
authors: AR
authors: Moossa
authors: M H
authors: MH
authors: Scott
authors: P
authors: P
authors: Haghighi
authors: S
authors: S
authors: Lee
mesh_terms: D000818:Animals; D002452:Cell Count / Q000187:drug effects; D003524:Cyclosporins / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D013154:Spleen / Q000033:anatomy & histology / Q000166:cytology / Q000187:drug effects*; D013194:Staining and Labeling
chemical_list: D003524:Cyclosporins