Somatic and reproductive outcomes in mice treated with cyclophosphamide in pre-pubertal age

Abstract

Disruption in the normal timing of female puberty, such as in pre-pubertal cancer treatments, can cause abnormal somatic development. We sought to evaluate the impact of cyclophosphamide (CTX) on the somatic, uterine, and ovarian, development of pre-pubertal mice. Pre-pubertal (day 18 of life) C57BL/ 6J female mice were randomized to receive placebo (group 1A and 1B), 200 mg/kg CTX (group 2A), or 120 mg/kg CTX (group 2B). Mice were euthanized on day 56 (A groups) or 95 (B groups) of life. Body weight and length, uterine and ovarian weight and right femur length and weight were measured, and ovarian insufficiency was assessed. Data were analyzed using ANOVA and t-test. Body weight and length did not differ among groups at time of euthanasia. The femur was shorter and weighed less in mice treated with CTX than in controls. Uterine weight was lower in group 2B than 1B (46.1 mg, 95% CI: 42.9-49.4, vs. 62.2 mg, 95% CI: 58.5-65.8, respectively; p = 0.005) and was lower in mice that developed ovarian insufficiency than in mice that did not ( p < 0.05). Ovarian weight was lower in mice treated with CTX, regardless of whether they developed ovarian insufficiency. Even with no observable effect on adult body length and weight, CTX treatment in prepubertal mice appears to negatively affect femur, uterine, and ovarian development. However, uterine development seems to be dependent on the hormonal status created by CTX more than on its direct effect.

Serum markers of ovarian reserve and ovarian histology in adult mice treated with cyclophosphamide in pre-pubertal age

“…This confirms our previous findings [7]. These figures are higher than what has been reported in human studies [15,22,23] and it is probably due to the different assessment methods of ovarian function in those studies (presence or absence of puberty or menses) compared to ours (serologic concentrations of AMH and FSH).…”

“…We previously classified the degrees of damage into three main categories (normal FSH, DOR, and POI) by serum FSH values [7]. However, in the current study we unified DOR and POI under the category 'ovarian insufficiency' and found that the histological damage to the ovary was identified by equally low AMH serum levels.…”

“…AMH and FSH measurements were used to characterize ovarian reserve as diminished versus normal. Ovarian function insufficiency was defined, as previously reported, as decreased ovarian reserve (DOR) by FSH values greater than 15 mIU/ml, and primary ovarian insufficiency (POI) by FSH values greater than 30 mIU/ml [7]. However, in the current study, we unified these two categories in a broader entity called 'ovarian insufficiency' and defined it by FSH values greater than 15 mIU/ ml.…”

Somatic and reproductive development in pre-pubertal mice treated with cyclophosphamide and subsequent estrogen replacement

“…We confirmed that CTX treatment impairs both long bone growth and bone mass accrual, yet with no observable effect on adult body length and weight, as we previously found [Detti et al 2013]. In addition, CTX treatment in pre-pubertal mice appears to negatively affect uterine development.…”

“…We previously described the deleterious effects of uterine and femur development after CTX exposure and corroborated those results with hormone serum levels; FSH levels were elevated in exposed mice compared to controls as a function of the development of acute ovarian failure [Detti et al 2013]. Reproductive function of treated mice was previously assessed by others [Meirow et al 2001], who found decreased fertility and an increased miscarriage/malformation rate.…”