DNA damage and macrophage infiltration in the ovaries of the long-lived GH deficient Ames Dwarf and the short-lived bGH transgenic mice

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Objective The aim of the study was to evaluate the role of growth hormone (GH) in DNA damage, macrophage infiltration and the granulosa cells number of primordial and primary follicles. Methods For these experiments six groups of female mice were used. Four groups consisted of Ames dwarf (Prop-1 df , df/df, n=12) and their normal littermates (N/df, n=12) mice, between sixteen and eighteen month-old, receiving GH (n=6 for df/df, and n=6 for N/df mice) or saline injections (n=6 for df/df, and n=6 for N/df mice). The other two groups consisted of ten to twelve-month-old bGH (n=6) and normal mice (N, n=6). Immunofluorescence for DNA damage (anti-γH2AX) and macrophage counting (anti-CD68) were performed. Granulosa cells of primordial and primary follicles were counted. Results Female df/df mice had lower γH2AX foci intensity in in both oocytes and granulosa cells of primordial and primary follicles (p<0.05), indicating less DNA double strand breaks (DSBs). In addition, GH treatment increased DSBs in both df/df and N/df mice. Inversely, bGH mice had higher quantity of DSBs in both oocytes and granulosa cells of primordial and primary follicles (p<0.05). Df/df mice showed ovarian tissue with less macrophage infiltration than N/df mice (p<0.05) and GH treatment increased macrophage infiltration (p<0.05). On the other hand, bGH mice had ovarian tissue with more macrophage infiltration compared to normal mice (p<0.05). Df/df mice had less granulosa cells on primordial and primary follicles than N/df mice (p<0.05). GH treatment did not affect the granulosa cells number (p>0.05). However, bGH mice had an increased number of granulosa cells on primordial and primary follicles compared to normal mice (p<0.05). Conclusion The current study points to the role of the GH/IGF-I axis in maintenance of oocyte DNA integrity and macrophage ovarian infiltration in mice.