V K Shreya, Raman Ramendra K, Kumar Shishir, S Bindhu, Farooq Juveriya, Noushida Nadira
Department of Anatomy, Yenepoya Medical College, Yenepoya Deemed to be University, Mangalore, IND.
Clinical Anatomy, Mayo Institute of Medical Sciences, Lucknow, IND.
Cureus. 2025 Jun 29;17(6):e86966. doi: 10.7759/cureus.86966. eCollection 2025 Jun.
Background The estrous cycle in female laboratory rats is a critical parameter in reproductive and toxicological research, traditionally assessed through stained vaginal cytology. However, staining procedures can be time-consuming, costly, and less feasible in resource-limited settings. This study evaluates the efficacy of unstained vaginal cytology as a rapid, economical alternative for staging the estrous cycle in female albino Wistar rats. Methods Vaginal smears were collected daily from 30-day-old female albino Wistar rats for 15 consecutive days using saline lavage. Unstained smears were examined under light microscopy to identify the predominant cell types - cornified epithelial cells, nucleated epithelial cells, and leukocytes - and to classify the estrous phases (proestrus, estrus, metestrus, diestrus). Results Distinct cytological profiles corresponding to each estrous phase were reliably observed without staining. Proestrus featured predominantly nucleated epithelial cells, estrus was marked by abundant cornified epithelial cells, metestrus showed increased leukocytes, and diestrus was characterized by a predominance of leukocytes with fewer epithelial cells. The average cycle duration was four to five days. The unstained method provided clear, rapid identification of cycle phases comparable to traditional stained techniques. Conclusion Unstained vaginal cytology offers a simple, cost-effective, and reliable method for estrous cycle staging in female albino Wistar rats. This approach is particularly suitable for laboratories with limited resources, facilitating reproductive and toxicological research without compromising accuracy.
背景 雌性实验大鼠的发情周期是生殖和毒理学研究中的一个关键参数，传统上通过阴道细胞学染色进行评估。然而，染色程序可能耗时、成本高，并且在资源有限的环境中不太可行。本研究评估了未染色阴道细胞学作为一种快速、经济的替代方法用于对雌性白化Wistar大鼠发情周期进行分期的效果。
方法 每天从30日龄雌性白化Wistar大鼠收集阴道涂片，连续15天使用生理盐水灌洗。在光学显微镜下检查未染色的涂片，以识别主要细胞类型——角质化上皮细胞、有核上皮细胞和白细胞——并对发情阶段（动情前期、动情期、间情期、动情后期）进行分类。
结果 在不染色的情况下可靠地观察到了与每个发情阶段相对应的不同细胞学特征。动情前期主要特征为有核上皮细胞，动情期以大量角质化上皮细胞为标志，间情期白细胞增多，动情后期的特征是白细胞占优势且上皮细胞较少。平均周期持续时间为四到五天。未染色方法能够清晰、快速地识别周期阶段，与传统染色技术相当。
结论 未染色阴道细胞学为雌性白化Wistar大鼠发情周期分期提供了一种简单、经济有效且可靠的方法。这种方法特别适合资源有限的实验室，有助于在不影响准确性的情况下进行生殖和毒理学研究。
