Cloprostenol and eCG influence oestrus synchronisation and uterine development in mice

The aim of this study was to investigate the efficacy of equine chorionic gonadotropin (eCG) and cloprostenol (CLO) administration on oestrus synchronisation, uterine development as well as serum LH and FSH concentrations in mice. One hundred and five KM mice were assigned into eCG-1, eCG-2, eCG-3, CLO-1, CLO-2, CLO-3 and control groups (CG, n = 15). The eCG-1, eCG-2 and eCG-3 groups were intramuscularly injected with 10, 20 and 40 IU eCG. CLO-1, CLO-2 and CLO-3 were intramuscularly injected with 10, 15 and 20 μg cloprostenol acetate. The results showed that 93.33% and 66.67% of synchronised mice displayed oestrus within 18.68-37.59 h. Oestrus numbers, oestrus onset time (EOT) and oestrus rate in CLO and eCG groups were greater than in CG (P < 0.05). EOT in CLO and eCG groups were 19.88 ± 2.91 h and 34.84 ± 5.05 h. Uterine weights of treatment groups were larger than CG. Uterine weights of the eCG group were higher than those in the CLO group. Uterine horn longitudial diameters (ULD) in treatment groups were larger than CG during the experiment. ULD in eCG-2 and eCG-3 were significantly greater when compared to CG (P < 0.05 or P < 0.01). On days 14 and 21, uterine horn transverse diameters (UTD) in CLO-1, eCG-1, eCG-2 and eCG-3 subgroups were significantly larger than that of CG (P < 0.05 or P < 0.01). Serum LH concentrations in eCG and CLO increased. Increments in eCG and CLO groups were greater than that of CG. FSH concentrations in eCG mice were higher than those in CLO and CG mice (P < 0.05) on day 21. Thus, eCG and cloprostenol treatments in mice can improve uterine development and promote the secretion of LH and FSH.