This study investigates the protective effects of roselle aqueous extract (RAE) against aristolochic acid (AA)-induced developmental nephrotoxicity in zebrafish embryos. Fluorescence imaging, immunohistochemistry, and real-time polymerase chain reaction (PCR) experiments were conducted. The results showed that pre-treatment with RAE significantly improved survival rates and reduced kidney malformations in AA-exposed zebrafish. Specifically, survival rates in the AA-treated group decreased to 81.11% by 72 hours post-fertilisation, whereas those in the AA+RAE (30 and 60 ppm) groups increased to 86.67–90%. Additionally, RAE pre-treatment reduced kidney malformation rates from 98.89% in the AA group to 75.56% and 63.33% in the AA+RAE (30 and 60 ppm) groups, respectively. Histological analysis revealed that RAE mitigated structural damage in the pronephric tubes, restoring their compact architecture. Molecular analysis using real-time reverse transcription (RT)-PCR further indicated that RAE reduced the expression of inflammatory markers, suggesting that its protective effects are mediated through the attenuation of AA-induced inflammation. These findings demonstrate that RAE exerts a protective role against AA-induced developmental kidney malformations in zebrafish, likely through its antioxidant and anti-inflammatory properties.

In March 2024, a health hazard associated with the consumption of food products containing red yeast rice (beni-koji), which could lead to renal dysfunction, was reported in Japan. Puberulic acid (PA) was identified as an unintentional contaminant in these products; however, information on PA toxicity remains limited. The toxicological profile of PA was evaluated in a 28-day subacute toxicity study in rats. Synthesized PA was administrated by gavage to 6-week-old Crl:CD(SD) rats at 0, 1, 3, or 10 mg/kg/day (male) or 0, 0.3, 1, or 3 mg/kg/day (female) over 28 days, and satellite groups were used to evaluate the reversibility over a 14-day period. Male rats in the 10 mg/kg group exhibited increased urinary glucose and serum creatinine levels compared to controls. Histopathological examination revealed vacuolation, necrosis, and regeneration of proximal tubules in kidneys of all rats in the male 10 mg/kg and female 3 mg/kg groups. After the 14-day recovery period, focal interstitial fibrosis was observed in one male rats from the high-dose group, whereas no renal lesions were detected in the remaining rats of either sex. These results suggest that PA-induced nephrotoxicity is largely reversible under the conditions studied, although residual chronic lesions may occur in severe cases. Apoptosis/necrosis and diffuse hyperplasia of the glandular stomach mucosa were observed in male 3 and 10 mg/kg and female 3 mg/kg groups but were absent after the recovery period. These results indicate that, under the study conditions, the no-observed-adverse-effect level for PA was 1 mg/kg/day for both sexes.

This study investigated the effects on ovarian development in adult rats irradiated with γ-rays at fetal, neonatal, weaning, and early sexual maturation. Female Fischer-344 (F344) rats mated with male rats and their F1 offspring were irradiated with a single dose of 0.5 or 2 Gy of γ-rays on gestation day 15 or 19 (GD15 or 19), or postnatal day 5, 20, or 49 (PND5, 20, or 49). F1 females were reared until 27 weeks of age and necropsied. HE-stained specimens of the reproductive organs were prepared for histological examination (n=10–22 per group). The corpus luteum and follicle numbers were also counted in all ovaries. In addition, PCNA-stained specimens were used to count the primordial follicles. At 2 Gy, corpora lutea and follicle depletion was observed in the GD15, PND5, and PND20 irradiation groups. Instead of lost follicles consisting of granulosa cells, numerous tubular structures composed of Sertoli-like cells similar to those found in the testes were noted. In the GD19 group, the ovaries showed less sensitivity to γ-rays. In the PND49 irradiation group, the number of corpora lutea was normal; however, the number of follicles, including primordial follicles, decreased. At 0.5 Gy, the ovaries appeared histologically normal in all the groups; however, the number of follicles decreased in the GD15 and PND5 irradiation groups. In conclusion, we found that the timing of γ-ray irradiation significantly affected subsequent ovarian development, and the degree of change depended on the γ-ray dose.

Hepatic iron overload is a common complication of human chronic liver diseases, including liver cirrhosis; however, the underlying mechanisms remain unclear. In the present study, we investigated the temporal changes in iron metabolism and the expression of iron-regulatory molecules during thioacetamide-induced liver cirrhosis in rats. Histopathological and biochemical analyses revealed that iron overload develops concurrently with the suppression of hepcidin expression in advanced cirrhosis. Hepatic expression of genes involved in cellular iron intake, storage, and export increased persistently in cirrhotic livers. The IL6-STAT3 and BMP6-SMAD pathways, which are the major intracellular mechanisms that induce hepcidin transcription, were inactivated in advanced cirrhosis. Furthermore, microRNA-135b-5p (miR-135b-5p), which targets JAK2 and SMAD5, key molecules of the IL6-STAT3 and BMP6-SMAD pathways, respectively, was highly upregulated in parallel with the progression of cirrhosis. These results indicate that inactivation of multiple hepcidin pathways, possibly mediated by miR-135b-5p upregulation, is responsible for hepatic iron overload in advanced cirrhosis. Our findings provide new insights into the mechanisms underlying iron dysregulation in liver cirrhosis.

Ectopic intestinal cysts are extremely rare in the rat liver. Here, we report a case of a spontaneous ectopic intestinal cyst in the liver of an 8-week-old male Crl:CD (SD) rat. Necropsy revealed a solitary white, firm nodule, approximately 3 mm in diameter on the diaphragmatic surface near the porta hepatis of the medial lobe of the liver. Histologically, the lesion exhibited a cystic structure lined with tissue resembling intestinal mucosa, located on the liver capsule. Periodic acid-Schiff and Alcian blue (pH 1.0) staining-positive mucous cells, similar to goblet cells, and Paneth cell-like cells containing eosinophilic granules were observed in the mucosal epithelium. Immunohistochemically, the mucosal epithelium demonstrated low proliferative activity, as confirmed by Ki-67 staining. The thin outer layer of the mucosa was positive for alpha-smooth muscle actin, suggesting the presence of the lamina muscularis or a poorly developed muscular layer. Based on the lesion’s location and histological features, this case was diagnosed as an ectopic intestinal cyst, likely resulting from persistence of the vitelline duct. To the best of our knowledge, there are no previous reports of ectopic intestinal cysts in the rat liver that include such detailed histochemical and immunohistochemical findings. This report provides valuable insights into congenital lesions of the rat hepatobiliary system.

Canine generalized ceroid lipofuscinosis (GCL) is a rare disease characterized by the deposition of lipofuscin in systemic organs and tissues. In this case report, we encountered a dog with GCL and performed a detailed histopathological examination. A 7-year-old male beagle was euthanized due to progressive weight loss and loose or bloody stools, without any neurological symptoms. Histopathologically, deposition of lipofuscin was observed in the parenchymal cells of systemic organs, particularly in the pancreatic acini and intestinal smooth muscle, accompanied by interstitial infiltration of macrophages. No neuronal loss was observed in the central nervous system, despite such findings and neurological symptoms being commonly associated with GCL. However, some lipofuscin deposition was evident in systemic organs, so the present case was diagnosed as GCL characterized by predominant deposition in the pancreatic acini and intestinal smooth muscle. This detailed description of the morphological features may contribute to a deeper understanding of lipofuscinosis.