Histo-morphological Effects of Carica papaya on Cadmium Induced Prefrontal-Cortex Damage in Adult Wistar Rats

Background: This research investigated the recuperative (restorative) effect of aqueous extract of Carica papaya fruit on cadmium induced prefrontal-cortex damaged in adult Wistar rats (Rattus norvegicus). Previous research reports have confirmed that cadmium toxicity results in cellular damage which is due to an increase in production of reactive oxygen species and prevention of the activities of antioxidant enzymes. Various parts of the brain (prefrontal cortex, hippocampus and so on) are majorly affected by cadmium as its induced damage.

Methods: 30 Wistar rats (70 g-190 g) were used for this research. The rats were randomly selected into six groups of five animals each. A single dose of 3CdSO4.8H2O (Cadmium sulphate octahydrous) 3.5 mg/kg body weights was administered intraperitoneally to three of these groups against control a group that was not exposed to Cadmium. Two groups were treated with different doses of Carica papaya fruit extract for the period of four weeks. After four weeks, the rats were sacrificed and organs excised, weigh and fixed in fixative for histological processing. The photomicrographs of the normal control, induced control and treated groups were observed and compared for histomorphological similarities and differences.

Results: Cadmium was observed to have caused a distortion, disruption and calcification in the cells and tissue of the prefrontal cortex. There was shrinkage of nuclei of the neurons in cadmium induced rats. It was also observed that cadmium caused a loss in function of cell in the process of protein biosynthesis. The morphology of the neuronal cells of rats treated with high and low doses of Carica papaya extract was found to be slightly normal with increased viable neuronal cells as compared with the neurons of the normal control group 1 animals, though the restorative effects of the high dose treated rats were more pronounced. Also, it was observed that the damage to the brain section neurons treated with vitamins C and E before induction was not pronounced. Moreso, loss in body weight were observed in cadmium induced group animals and over treatment with Carica papaya, gain in the rats body weight was observed in the treatment animal groups as compared with the body weight of rats in normal control. Animal body weight before cadmium inoculation, after inoculation and before animal sacrifice were compared across all the groups and it was found that, there was a progressive increase in rats body weight (99±2,35≤ 150 ±3.21), (120±2.32≤189±3.21) and (135±1.35≤175±2.15) respectively which was significant at P ≤ 0.05.

Conclusion: It can be ascertained from this present study that Carica papaya has ameliorative properties against deleterious effects of cadmium on the neurons and neuroglia of the prefrontal-cortex in Wistar rats which is dose dependent.