EXPERIMENTAL EVALUATION OF SELECTED HAEMOSTATIC, AND IMMUNOLOGICAL EFFECTS OF ESTRADIOL VALERATE IN FEMALE ALBINO WISTAR RATS

Oral estradiol valerate (EV), an estrogen medication used in hormone replacement therapy for menopausal symptoms and low estrogen levels can influence coagulation and immune responses. However, the integrated effects of graded EV exposure on haemostatic and inflammatory parameters are not fully understood. This study evaluated the effects of EV on some haemostatic and inflammatory parameters in female albino Wistar rats. Twenty female rats weighing 150 – 200 g were divided into four groups: a control group receiving distilled water and three treatment groups received graded doses of estradiol valerate, 0.02 mg/kg, 0.04 mg/kg, 0.07 mg/kg body weight respectively. The EV was administered through oral gavage daily for 28 days. Blood samples were collected via cardiac puncture (left ventricle of the heart). The evaluated variables included platelet (PLT) count, prothrombin time (PT), activated partial thromboplastin time (APTT), Factor VII, and Factor VIII using manual methods and enzyme linked immunosorbent assay (ELISA). Serum interleukin-6 (IL-6) and interleukin-10 (IL-10) were measured using sandwich ELISA. Results were expressed as mean ± standard deviation (SD) and a p < 0.05 was considered statistically significant. Data generated were analyzed using Statistical Package for Social Sciences (SPSS) version 27.0, windows 10. Differences among the groups were tested using one-way Analysis of Variance (ANOVA), followed by post-hoc analysis. Body weight increased in all groups, from 165.00 ± 11.18 to 182.00 ± 7.14 g in controls, 177.00 ± 8.92 to 196.80 ± 5.40 g in the high-dose group, 155.60 ± 6.02 to 177.60 ± 6.27 g in the medium-dose group, and 165.00 ± 11.18 to 182.00 ± 7.14 g in the low-dose group. Significant differences were observed for PLT (F = 58.89, p < .001), PT (F = 6.93, p = .003), APTT (F = 8.24, p = .002), factor VII (F = 43.17, p < .001), factor VIII (F = 8.54, p = .001), IL-6 (F = 3.68, p = .034), and IL-10 (F = 16.95, p < .001). The high-dose EV group showed the highest platelet count (780.80 ± 38.77 × 10⁹/L), shortest PT (33.40 ± 2.07 s) and APTT (11.46 ± 0.97 s), and lower factor VII and VIII concentrations than the control group. IL-6 was highest in the medium-dose group, whereas IL-10 was lowest in the high-dose group.
In conclusion, graded EV administration significantly altered selected haemostatic and immunological parameters in female albino Wistar rats. The responses were not uniformly dose dependent, indicating that EV may exert complex, parameter-specific effects on haemostasis and cytokine regulation. Further studies should incorporate broader panel of inflammatory biomarkers to better characterize inflammatory response associated with estradiol valerate. This finding contributes to the understanding that estrogen-related haemostatic effects involve multiple pathways that may respond differently to the same hormonal exposure, rather than a simple global activation or suppression of coagulation. The study also adds to knowledge by providing experimental evidence that estrogen-mediated immune regulation may be concentration dependent and non-linear.