This study evaluated age-related changes in the testicular morphophysiology of the cane rat ( Thryonomys swinderianus ) using histological, histochemical, and sex hormonal profile approaches. Twenty (20) pathogen-free male cane rats were used for the investigation. Cane rats were divided into four groups: prepubertal (≤4 months), pubertal (>4 ≤12 months), adult (>12 ≤30 months), and aged (>30 months) of 5 rats each. Blood was collected from the different cane rat groups and processed for sex serum hormonal levels. Testes were also excised and processed routinely for variations in histology, histochemistry (using Masson's trichrome [MT] and Periodic acid–Schiff [PAS]), and histomorphometric evaluations using GIMP2 software. Testosterone concentrations were significantly elevated ( P < 0.05) in the prepubertal to adult, while there were no significant differences ( P > 0.05) in this hormone between adult and aged. The concentrations of follicle-stimulating hormone (FSH) decreased significantly ( P < 0.05) for prepubertal, pubertal, and adult, respectively. There were no significant differences ( P > 0.05) between adult and aged for FSH and luteinizing hormone. Histologically, there were scanty interstitial cells, lack of patent lumen, and incomplete spermatogenetic cell series in prepubertal compared to other age groups. Testicular capsular (MT and PAS) staining intensity increased with age advancement, while in the parenchyma, remarkably high intensity was displayed by the pubertal compared to others. Seminiferous tubular and luminal diameters (LD) significantly ( P < 0.05) increased with advancing age whereas epithelial height (EH) was markedly increased in pubertal relative to other groups. In conclusion, these sets of data have shown that reproductive activity is directly related to age and is at maximum in adult cane rat.

Introduction: Vimentin is a cytoskeletal protein that is expressed in different regions of the testicular and epididymal parenchyma with principal function of structural support. There is dearth of literature on testicular and epididymal vimentin expression in different ages of African greater cane rat (AGCR). Hence, this study investigated vimentin expression profiles in the testis and epididymis of prepubertal to aged AGCR. Methods: Twenty healthy AGCR procured from a commercial cane rat farm were used for this study. The rats were randomly divided into 4 groups (n=5) as follows; Group 1: prepubertal (1-4 months), Group 2: pubertal (5-11 months), Group 3: adult (12-30 months) and Group 4: aged (>30 months). Testicular and epididymal samples were harvested and processed for immunohistochemistry using anti-vimentin marker. Results: Testicular vimentin was expressed in the interstitium, perinuclear region and basal aspect of Sertoli cells and along the tip of elongated spermatids. In the various segments of the epididymis, vimentin expression was confined to the peritubular coat and interstitium (stroma and perivascular components). Vimentin staining intensity in the testis was significantly higher (p < 0.05) in the adult group relative to others and appeared to increase with age. For the epididymis, significantly higher (p < 0.05) vimentin intensity was observed prepubertally and decreased with age advancement. Significance: The result from this study has demonstrated that the testes of the adult AGCR as well as the epididymal segments of the prepubertal rat had increased vimentin intensities which are indicative of marked reproductive activity and robust content of undifferentiated cells respectively.

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