Hristiyana Kanzova

Microplastics (MPs) are widespread environmental contaminants, yet their effects on reproductive and early ontogenetic development remain insufficiently understood. The present study aimed to evaluate the ef-fects of chronic pregestational and gestational exposure to polystyrene microplastics (PS-MPs) with particle sizes of 1 μm (G1) and 5 μm (G5) on embryonic and early postnatal development in Wistar rats, using com-bined ultrasonographic and morphometric assessment.Juvenile animals were subjected to a 30-day oral exposure to PS-MPs at a dose of 0.1 mg/day suspended in drinking water until sexual maturity. After mating, exposure in females continued throughout pregnancy, allowing the modeling of combined pregestational and gestational exposure.Ultrasonographic evaluation on gestational day 10 revealed no significant intergroup differences, sug-gesting unaffected early implantation and initial embryonic development. In contrast, gestational day 18 demonstrated statistically significant reductions in the main ultrasonographic parameters in exposed groups compared to controls, with the most pronounced alterations observed in G1, indicating a size-dependent effect during late gestation.Postnatal morphometric analysis demonstrated a tendency toward lower body weight and body length in offspring from exposed groups on postnatal days 2 and 21 (PND 2 and PND 21), while the physiological growth pattern remained preserved. Smaller particles (1 μm) induced more pronounced alterations than 5 μm particles.In conclusion, maternal exposure to PS-MPs was associated with measurable, phase-dependent changes in embryonic and postnatal development in Wistar rats, with effects tending to be more pronounced following exposure to smaller particles and during late gestation. These findings suggest that particle size may influence the biological activity of MPs and support the need for further investigation into their potential long-term reproductive effects.

Microplastics (MPs) represent an increasing environmental and biological concern, with their potential effects on early development and physiological homeostasis still not fully elucidated. The present study aimed to evaluate the effects of chronic juvenile exposure to 1 μm and 5 μm polystyrene microplastics (PS-MPs) on growth, organ indices, and endocrine profile in Wistar rats. A total of 36 juvenile Wistar rats (18 males and 18 females) were orally exposed to PS-MPs (0.1 mg/day) from postnatal day (PND) 21 to PND 61. Body weight dynamics were monitored throughout the experimental period, while at the end of exposure organ indices and serum levels of testosterone and estradiol were assessed. Exposure to PS-MPs was associated with delayed body weight gain, with more pronounced effects observed following exposure to 1 μm particles. Organ-specific and sex-dependent alterations were observed, predominantly affecting brain, lung, and spleen indices, as well as reproductive organs, with effects varying according to both sex and particle size. In addition, significant changes in serum sex hormone levels were detected, characterized by decreased testosterone in males and decreased estradiol in females. In conclusion, juvenile exposure to PS-MPs was associated with sex- and size-dependent alterations in growth dynamics, organ indices, and endocrine status in Wistar rats, suggesting potential systemic physiological effects of microplastics during early development.

Microplastic pollution has attracted significant attention in recent years due to evidence that these particles can accumulate in organisms’ tissues and organs and induce adverse health effects, with oxidative stress being a key underlying mechanism of toxicity. The present study investigated the effects of polystyrene microplastics (0.1 μm in diameter) administered at a dose of 0.1 mg/day/animal for 4 weeks, followed by a 2-week recovery period without exposure, on oxidative stress markers in the liver, kidney, and spleen and on hematological and blood biochemical parameters in mice. The results showed a statistically significant increase in white blood cell counts, including lymphocytes, granulocytes, and monocytes, at week 5, indicating the development of an inflammatory response. During the last week of the recovery period (week 6), values returned to levels that approached baseline. Changes in lipid peroxidation demonstrated an induction of oxidative stress, accompanied by alterations in glutathione levels and antioxidant enzyme activities, with a tendency toward recovery after cessation of polystyrene microplastic exposure. In conclusion, these findings demonstrated that even short-term exposure to low doses of polystyrene microplastics could trigger oxidative stress and inflammatory responses, highlighting their potential health risks and the need for further investigation into their long-term biological effects.

Increasing environmental contamination with microplastics (MPs) raises significant concerns regarding their potential impact on reproductive health. This study evaluated the effects of prolonged oral exposure to fluorescent polystyrene microplastics (FPS-MPs) of different sizes on the male reproductive system in Wistar rats. Juvenile male rats at 21 days of age were exposed to FPS-MPs of 1 µm and 5 µm for 52 days, covering the period of sexual maturation and a complete spermatogenesis cycle. Body weight, reproductive organ indices, serum levels of testosterone (T), estradiol (E2), follicle-stimulating hormone (FSH), and luteinizing hormone (LH), as well as sperm motility and morphology, were assessed. Reproductive potential and accumulation of microplastics in reproductive tissues were also evaluated. No significant differences were observed in body weight or most reproductive organ indices, except for a slight reduction in the left epididymis index in the group exposed to 5 µm particles. FPS-MPs induced size-dependent changes in the hormonal profile, including decreases in T and E2 and compensatory increases in FSH and LH, as well as impairments in sperm quality, which were more pronounced in rats exposed to smaller particles. In conclusion, fertility potential remained preserved, while FPS-MPs accumulated in the testes and epididymides, demonstrating subclinical, size-dependent effects on the male reproductive system.

The difficult-to-heal wounds continue to be a problem for modern medicine. Chitosan and diosgenin possess anti-inflammatory and antioxidant effects making them relevant substances for wound treatment. That is why this work aimed to study the effect of the combined application of chitosan and diosgenin on a mouse skin wound model. For the purpose, wounds (6 mm diameter) were made on mice’s backs and were treated for 9 days with one of the following: 50% ethanol (control), polyethylene glycol (PEG) in 50% ethanol, chitosan and PEG in 50% ethanol (Chs), diosgenin and PEG in 50% ethanol (Dg) and chitosan, diosgenin and PEG in 50% ethanol (ChsDg). Before the first treatment and on the 3rd, 6th and 9th days, the wounds were photographed and their area was determined. On the 9th day, animals were euthanized and wounds’ tissues were excised for histological analysis. In addition, the lipid peroxidation (LPO), protein oxidation (POx) and total glutathione (tGSH) levels were measured. The results showed that ChsDg had the most pronounced overall effect on wound area reduction, followed by Chs and PEG. Moreover, the application of ChsDg maintained high levels of tGSH in wound tissues, compared to other substances. It was shown that all tested substances, except ethanol, reduced POx comparable to intact skin levels. Therefore, the combined application of chitosan and diosgenin is a very promising and effective medication for wound healing.