Effects of young coconut juice on the numbers of argyrophil endocrine cells in the gastrointestinal tract of male rats: Novel preliminary findings

Abstract

Apart from calcium itself, there are many factors including vitamin D and estrogen, that play important roles in bone formation. Hormones, especially estrogen, used for replacement therapy is highly effective at reducing the rate of bone loss and can also replace lost bone in postmenopausal women. Estrogen replacement therapy has been proposed to prevent bone loss in males as well as in females. Estrogen, however, has been considered to be one of the hormonal risk factors of benign prostatic hyperplasia and prostate cancer and also other side effects. With this background, in the present study, young coconut juice (YCJ), that is known to contain the phytoestrogen, -sitosterol, was investigated for its possible beneficial effects on delaying osteoporosis using a male orchidectomized rat model, and as a replacement for estrogen replacement therapy. In the present study we used the Grimelius stain which is a broad endocrine cell marker, especially in the gastrointestinal (GI) tract to quantify the argyrophil endocrine cells and if possible to relate this to reflex GI functions, e.g. calcium absorption, GI motility etc. that might have an influence on osteoporosis. There were five groups of rats (6 per group) included in this study. The first group consisted of sham-operated rats, the second group consisted of orchidectomized (orx) rats, and the third group consisted of orx rats injected intraperitoneally with exogenous estrogen (2.5 g/kgBW of estradiol benzoate, EB) five days a week for two weeks. The fourth group consisted of orx rats that received YCJ (100 mL/ kgBW/day) and the fifth group was sham-operated rats receiving YCJ (100 mL/kgBW/day) for two weeks. After sacrifice, the GI tract including stomach, small and large intestines were removed, fixed and paraffin embedded for routine H&E and Grimelius silver staining. Most of the argyrophil cells were dispersed in the mucosa, particularly in the basal mucosa and were generally round or spindle shaped and occasionally spherical. There was a regional distribution of the argyrophil endocrine cells in all regions of the GI tract: stomach, duodenum, jejunum, ileum and colon, and that of the orx group had the lowest numbers. Estradiol benzoate (EB) injection and YCJ feeding in the orx group reversed this phenomenon in all regions of GI tract except for the colon. The sham+YCJ group had the highest number of argyrophil cells. Regression correlation analysis between the argyrophil cell numbers and serum estrogen and testosterone levels were R2 0.0054 and 0.0355, respectively. The changes in the density of the GI argyrophil cells in the orchidectomized rats in the present study may contribute to the GI function abnormality e.g. GI motility, GI calcium absorption, GI hormone production and secretion etc. frequently encountered in patients with andropausal or elderly osteoporosis. Such impairment of calcium and probably other minerals in the orx rats could be reversed by exogenous estrogen e.g estradiol benzoate (EB) supplement or by phytoestrogen e.g. YCJ feeding as preliminarily detected by the numbers of argyrophil endocrine cells in this study.

Keywords

• young coconut juice
• Cocos nucifera
• osteoporosis
• grimelius staining
• gastrointestinal tract