Ultrastructural changes in lactotrophs and somatotrophs of alloxan-induced diabetic rats and the possible protective effect of alpha-lipoic acid

ABSTRACT

Alteration in the cellular composition of the anterior pituitary gland could be involved in both prolactin and growth hormone disturbances in cases of poorly controlled diabetes. This study was conducted to investigate the ultrastructural changes in both somatotrophs and lactotrophs of diabetic rats and to investigate the possible protective effect of alpha-lipoic acid. Thirty adult male rats were randomly divided into three equal groups group A [control], group B [alloxan-induced diabetic rats], and group C [alloxan-induced diabetic rats that received alpha-lipoic acid]. In rats of groups B and C, diabetes was induced by a single intraperitoneal injection of alloxan monohydrate. In animals of group C, alpha-lipoic acid was given intraperitoneally during the period of the experiment. Twelve weeks after induction of diabetes, specimens of the pituitary gland were processed for transmission electron microscopic examination and a morphometric study was conducted. Somatotrophs of diabetic rats showed condensed nuclei, dilated Golgi saccules, and dilated rough endoplasmic reticulum cisternae. Further, some lactotrophs showed corrugated or condensed nuclei, dilated Golgi saccules, and relatively fewer granules. In both somatotrophs and lactotrophs of diabetic rats, the number of cytoplasmic granules was significantly decreased as compared with that of control rats. In addition, a significant increase in the percentage of empty granules to the total number of granules was recorded. However, the total number of granules and the percentage of empty granules to the total number in both somatotrophs and lactotrophs were significantly reduced in diabetic rats treated with alpha-lipoic acid as compared with untreated diabetic rats. The spectrum of changes in lactotrophs and somatotrophs of uncontrolled diabetic rats was found to be corrected by alpha-lipoic acid and therefore alpha-lipoic acid is recommended as a form of adjuvant therapy for diabetes