Lentivirus vector-mediated mitofusin-2 overexpression in rat ovary changes endocrine function and promotes follicular development in vivo

The aim of the present study was to evaluate the expression and effect of rat mitofusin-2 (rMfn2) in the ovaries and other organs in rats. Rat models were developed by the intraovarian microinjection of an rMfn2-overexpressing lentiviral vector. Lenti-green fluorescent protein (GFP)-rMfn2 was microinjected into rat ovaries at a dosage of 2×106 tuberculin units virosome (n=25) and lenti-GFP was microinjected as a control (n=25). The expression of rMfn2 in the ovaries and other tissues was observed by fluorescence microscopy on days 7, 15, 30, 45 and 60 after the microinjection (n=5/day from each group). The serum levels of estradiol (E2), progesterone (P), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were determined by radioimmunoassay. Western blotting was used for the quantitative analysis of the expression of rMfn2 and the progesterone receptor (PR), estradiol receptor (ER), luteinizing hormone receptor (LHR) and follicle-stimulating hormone receptor (FSHR). The expression of rMfn2 was detected on day 7 after infection, increased with time and was maintained efficiently until day 60. In addition, rMfn2 was highly expressed in the fallopian tubes, uterus, cardiac muscle, liver and kidney, but expressed at a low level in adipose tissue. The serum levels of E2 and P in the model group were significantly increased compared with those in the control group, whereas the FSH and LH levels showed no significant difference between groups. The expression levels of the ER and PR in the model group were higher than those in the control group; however, no significant difference was observed between groups for the expression levels of LHR and FSHR. These findings suggest that the intraovarian microinjection of lenti-GFP-rMfn2 resulted in a significant time-dependent overexpression of rMfn2 in various organs, and that rMfn2 overexpression in rat ovaries changed the endocrine function and promoted follicular development.