comparative histological, immunohistochemical, and biochemical study of the effect of green tea extracts or chromium picolinate administration on the white visceral adipose tissue and liver in albino rats fed on high-fat diet

Obesity has become a major health problem, as a growing proportion of the population worldwide is overweight. The coincidence of obesity, insulin resistance, hypertension, dyslipidemia, and hepatic steatosis is commonly referred to as the 'metabolic syndrome'. The investigation of the antiobesity properties of food components is a popular field of research and one of these natural agents of interest is green tea extract [GTE]. Nevertheless, chromium picolinate [CP] is also postulated to have an effect on the body fat composition. The present study aimed to assess the changes in the visceral white adipose tissue and the liver of adult male albino rats that are fed on high-fat diet [HFD] following administration of GTE or CP supplements histologically, immunohistochemically, and biochemically. A total of 60 adult male albino rats [120-150g] were randomly assigned into four groups. Group I [the control group] included 30 rats and were subdivided into three equal subgroups [Ia, Ib, Ic]; all were fed on standard rat chow. Groups Ib and Ic were given GTE and CP, respectively, orally through an orogastric tube. Group II included 10 rats that were allowed a free access to HFD. Group III [the GTE and HFD group] included 10 rats that received GTE orally [200 mg/kg body weight/day] in conjunction with HFD. Group IV [the CP and HFD group] included 10 rats that received CP orally [80 micro g/kg body weight/day] in conjunction with HFD. The experiment continued for 3 months. Perinephric white adipose tissue [PWAT] and liver specimens were dissected from all rats at the end of the experiment for histological and immunohistochemical examination. Blood samples were taken for estimation of fasting blood glucose [FBG] and fasting blood insulin [FBI] levels. Histologically, groups Ib and Ic revealed almost the control pattern of the liver and PWAT similar to group Ia. Group II showed focal areas of cellular infiltration and congestion of the blood vessels of the liver sections. Most hepatocytes appeared swollen with cytoplasmic vacuolation. PWAT revealed a marked increase in the amount and size of the adipocytes. Groups III and IV revealed almost the control pattern of the liver except for few areas of cellular infiltrations in group IV. Groups III and IV showed a marked decrease in the amount of PWAT, which was more remarkable in group IV. Decrease in the size of many adipocytes was more manifested in group IV. Immunohistochemically, increased expression of insulin receptors in the adipocytes of PWAT and to a lesser extent in the hepatocytes of group III was noticed. Group IV showed more noticeable increased expression of insulin receptors compared with group III. Biochemically, FBI in the obesity group was higher as compared with the control group. Groups III and IV revealed a significant decrease in the FBI level. Fasting blood glucose level showed significant increase in group II only. Supplementation with either GTE or CP may be useful as antiobesity agents and can be used to prevent the impact of obesity on the liver and to improve insulin resistance

Histological study of the femur and the lumbar vertebrae in ovariectomized adult albino rats following administration of collagen hydrosylate

Introduction: Osteoporosis is the most common skeletal disorder that has become a leading cause of morbidity and mortality worldwide. Its prophylaxis and therapy are still unresolved challenges

Aim of the study: The aim of the study was to investigate the possibility that collagen hydrosylate [CH] can ameliorate osteoporotic bone loss in ovariectomized rats with special reference to bone mineral content [BMC], some biochemical parameters of bone turnover, and histology

Materials and methods: Forty adult female albino rats [180-200 g] were categorized into four equal groups: a sham-operated control group [group I], a sham-operated CH-treated group [group II], an ovariectomized group [group III], and a CH-treated ovariectomized group [group IV]. The experiment continued for 12 weeks. At its end, the animals were sacrificed under anesthesia. Blood samples were collected for estimation of serum calcium, osteocalcin, bone-specific alkaline phosphatase, and C-terminal telopeptide of type I collagen [CTX]. The left femora and lumbar vertebrae were excised for histological examination by H and E and Gomori's trichrome stains. The area percentage of collagen was further assessed using an image analyzer. The right femur of each rat was used for BMC measurement by energy-dispersive X-ray analysis

Results: In sham-operated CH-treated rats [group II] there was no significant variation in bone turnover markers and BMC as compared with their respective controls. Normal bone microstructure was depicted as well. In group III rats, ovariectomy [OVX] was associated with enhanced bone turnover as depicted by significant decrease in the mean value of serum calcium, whereas osteocalcin, bone-specific alkaline phosphatase, and CTX revealed significant increase compared with controls. Moreover, an evident reduction in bone calcium content was depicted in the femora of this group. Histologically, evidence of bone resorption was manifested in the femoral diaphysis and lumbar vertebrae with multiple resorption cavities, irregularly eroded endosteal surface containing osteoclasts, and thinned out bone trabeculae along with wide bone marrow cavities. A significant decrease in bone collagen content of both cortical and trabecular bones was evidenced in trichrome-stained sections. In contrast, CH administration after OVX [in group IV] reduced bone turnover markers and improved BMC as well as histological characteristics of examined bones as compared with the OVX group

Conclusion: The study suggested that CH may be a potentially useful agent in preventing bone loss due to ovarian hormone deficiency