Effect of Combretum hereroense Root Extract on Estrous Cyclicity and Vaginal Cytology in Female Albino Rats with Experimentally Induced Reproductive Dysfunction

Résumé

Infertility and reproductive dysfunction are still significant reproductive health issues, especially in environments with restricted access to traditional reproductive health care. Traditional medicines could also be a source of compounds with reproductive activities, but need to be tested for reproductive efficacy and safety. In parts of Kenya (in Baringo County) Combretum hereroense Schinz is traditionally used for reproductive health issues. However, information on its effects on estrous cyclicity is limited. This study examined the effect of C. hereroense root extract on estrous cycle characteristics and vaginal cytology in female albino rats with experimentally induced reproductive dysfunction. Thirty-six female albino rats aged 8–10 weeks were randomly allocated to six groups of six animals. The groups consisted of a normal control, negative control, positive control treated with Gynaecosid®, and three extract-treated groups receiving 400, 800 and 1200 mg/kg body weight of C. hereroense root extract. Reproductive dysfunction was induced after synchronization of the estrous cycle. Treatments were administered orally once daily for 14 days. Daily vaginal smears were used to determine estrous cycle length, cycle regularity and the proportion of days spent in proestrus, estrus, metestrus and diestrus. Vaginal cytology was assessed by recording leukocytes, cornified epithelial cells and nucleated epithelial cells. Differences in continuous variables were tested using one-way analysis of variance followed by Tukey's HSD test, while chi-square tests were used for categorical variables. Significant differences were observed among the six groups in leukocyte count (F (5,30) =79.42, p<0.001), cornified epithelial cell count (F _0.05(5,30) =68.37, p<0.001), nucleated epithelial cell count (F _0.05(5,30) =31.84, p<0.001) and estrous cycle length (F _0.05(5,30) =52.63, p<0.001). The negative control group had the longest cycle (8.7±0.8 days) and the highest number of leukocytes (68.5±6.3 cells/field), the lowest numbers of nucleated epithelial cells (10.5±2.1 cells/field) and cornified epithelial cells (12.3±3.6 cells/field) in this group. Mean cycle length decreased with increasing extract dose, from 6.9±0.6 days at 400 mg/kg to 5.3±0.5 days at 800 mg/kg and 4.6±0.4 days at 1200 mg/kg. At 1200 mg/kg, the three vaginal cytological parameters were comparable to those recorded in the Gynaecosid® group. Cycle regularity and the distribution of days across the four estrous stages did not differ significantly between groups (p>0.05). Overall, administration of C. hereroense root extract was associated with shorter estrous cycles and changes in vaginal cell composition in rats with experimentally induced reproductive dysfunction, with the effects being more pronounced at the higher doses. The 1200 mg/kg dose produced values close to those observed in the Gynaecosid® group. Further studies are needed to clarify the hormonal and cellular mechanisms underlying these effects and to establish the effective and safe dose range of the extract.