Effect of inhibiting connexin 43 expression on the expression of rat glial cell growth factors in prolactinomas

Abstract

Objective To investigate the effect of inhibiting connexin 43 (Cx43) expression on the expression of rat glial cell growth factor in prolactinomas. Methods Forty-eight female rats were randomly assigned to normal, simple estradiol, estradiol+ carbenoxolone, and simple carbenoxolone groups by the completely randomized method (n=12 in each group). A model of rat prolactinoma was induced by estradiol. The normal group did not accept drug treatment; the simple estradiol group was injected estradiol intramuscularly (3 000 mg/kg, once a week, for 13 weeks); 10 weeks after injection of estradiol, the estradiol+ carbenoxolone group injected carbenoxolone via subarachnoid (once a week, for 3 weeks); and the simple carbenoxolone group only injected carbenoxolone for 3 weeks. The changes of body mass of pituitary and histomorphology were observed. Western blot was used to detect the expression levels of Cx43 and glial growth factor (GGF). Results The pituitary weights of the normal, simple estradiol, estradiol+ carbenoxolone and simple carbenoxolone groups were 51.0±0.4 mg, 93.3±1.0 mg, 52.7±2.1 mg and 68.5±1.3 mg, respectively. There were significant differences (F=786.73, P<0.01); the relative expression quantities of Cx43 were 8.0±2.2%, 34.7±4.0, .9.3±3.1%, and 15.3 ±3.8%, respectively, and the relative expression quantities of GGF were 17.7±5.2%, 46.9±1.4%, 15.8±3.6%, and 20.0±2.3%, respectively. There were significant differences (F=1051.51. P<0.01; F=806.58, P<0.01). The pituitary histopathological morphology of the estradiol+ carbenoxolone group was close to the normal group and the simple carbenoxolone group. Conclusions Inhibition of pituitary Cx43 expression may inhibit the GGF expression, thereby inhibiting the growth of pituitary prolactinomas in rats. Key words: Prolactinoma; Gap junction proteins; Gap junction inhibitor; Glial cell growth factor; Rats