Pathology of the Male Reproductive System PDF

PATHOLOGY OF THE MALE REPRODUCTIVE SYSTEM Annas Salleh Department of Veterinary Laboratory Diagnosis Faculty of Veterinary Medicine Universiti Putra Malaysia 43400 Serdang, Selangor MALAYSIA ...

PATHOLOGY OF THE MALE REPRODUCTIVE SYSTEM Annas Salleh Department of Veterinary Laboratory Diagnosis Faculty of Veterinary Medicine Universiti Putra Malaysia 43400 Serdang, Selangor MALAYSIA  General Considerations The main function of the male reproductive tract is to produce and deliver spermatozoa into the female reproductive system The spermatozoa is produced in the seminiferous tubules through transformations of cells (known as germinal cells) to become spermatogonium, then become primary spermatocytes, secondary spermatocytes, spermatids and spermatozoa The transformation is known as spermatogenesis, and is controlled by testosterone produced by the interstitial tissue of the testes The spermatozoa are stored and mature in the epididymis while secretions of the various accessory gland produce semen for delivery The germinal cells of seminiferous tubules are heat sensitive but not the cells of the interstitial tissue. Therefore, heat will effect spermatogenesis but not testosterone production  General Considerations Sg S Sd Lc Sp 50 m Photomicrograph of the seminiferous tubules of an adult male lesser mouse deer. It shows an active seminiferous tubule, cut in transverse section, where the processes of spermatogenesis and spermiogenesis. Spermatogonia (Sg), the germ cells are found in basal layer of seminiferous epithelium. During spermatogenesis, the spermatogonia divide to give rise to primary spermatocytes (Sp), Secondary spermatocytes (Sd), spermatid (S) and finally spermatozoa. Leydig cells (Lc) are observed among the interstitial cells found in the connective tissue (H&E, 400x, Bar = 50 m).  General Considerations Hormonal control of spermatogenesis. FSH, follicle-stimulating hormone; LH, luteinizing hormone; LHRH, luteinizing hormone–releasing hormone. (Gartner and Hiatt, 2007).  General Considerations To fulfill the function, the male system consists of several main organs: scrotum protect the testes and maintain the testicular temperature to ensure spermatogenesis testes where spermatogenesis occurs involving germinal epithelium of the seminiferous tubules produces testosterone, the male hormone by the interstitial tissues epididymis storage and maturation of the spermatozoa Accessory glands Produce secretions to provide nutrients to the spermatozoa Penis delivery of the spermatozoa  General Considerations UB, urinary bladder; A, Ampullae; VG, seminal vesicle gland; PG, prostate gland; BG, bulbo-urethral gland; SF, sigmoid flexure; DD, ductus deferens; P, penis; GP, glans penis.  Pathology of Testes Testicular Degeneration is the most frequent cause of poor quality semen that leads to reduced fertility in male animals Associated with exposure to high temperature = degenerative changes observed in the cells of testis, particularly the cells of seminiferous tubules Can be localised or generalised, uni- or bilateral Causes: 1. thermal such as: thick scrotal fat and hydrocoele that prevent heat regulation by the scrotum high environmental temperature of more than 32oC 2. Infections 2. localised or systemic infections involving tunica vaginalis, scrotum or epididymis leading to: heat generation by inflammatory process adhesion of organs  Pathology of Testes Testicular Degeneration 3. nutritional factors, which include: deficiencies in vit. A, phosphorus and protein vit. A deficiency affect the gonad by suppressing the release of gonadotrophic hormone from the pituitary gland 4. vascular lesions Testicular torsion or the use of emasculator as for castration lead to infarction. Incomplete infarction may left viable Leydig cells and retain male characteristics Inflammation of the testicular artery such as caused by migrating larvae or equine arteritis virus infection in horses Vascular hamartoma in dogs 5. Hormonal factor Spermatogenesis is controlled by follicular-stimulating hormone (FSH) and luteinizing hormone (LH) FSH regulates spermatogenesis while LH controls testosterone secretion by the Leydig cells  Pathology of Testes Testicular Degeneration Pathology: Grossly, the affected testis: appears soft and flabby but the size is either normal or smaller does not bulge on cut surface shows fibrosis in chronic cases leading to the organ to be smaller but firm Histologically, there are: failure of maturation of spermatozoa and degenerated spermatids in acute cases many necrotic spermatids with multinuclear giant cells degenerative changes in precursor of spermatids in the form of cytoplasmic vacuolation, pyknosis while the basement membrane denuded of cells in advanced cases  Pathology of Testes Testicular Degeneration the tubules collapse and the interstitial connective tissue appears thickened in the early stage, there increased number of abnormal and immature sperm but with the progress of the condition, the sperm production is severely reduced and the semen is thin and milky or watery Pathology of Testes Pathology of Testes  Pathology of Testes Cryptorchidism = incomplete descent of the testes, either uni or bilateral an inherited condition that leads to sterility of the affected testis Pathogenesis: Failure to descent Testicular temperature Spermatogenesis Normal interstitial tissues testosterone Reduced sperm No sperm Normal libido (Unilateral) (Bilateral) Reduced Fertility Sterility  Pathology of Testes Cryptorchidism retained testis appears small, flabby and darker seminiferous tubules are well developed but devoid of sperm or showing incomplete spermatogenesis with reduced number of spermatogenesis cells The interstitial tissues are normal and functioning due to the devoid of spermatogenesis cells in the tubules but normal interstitial tissues, the affected testis appears to compose largely of connective tissue In some cases, testicular seminoma developed.  Pathology of Testes Cytoplasmic Male Sterility: Hybrid is the outcome of combining, through sexual reproduction, the genetics of two animals of different breeds, species or genera Associated with the numbers of chromosomes that resulted in intermediate performance between their parents Some cross-breeding resulted in sterility: the mule, a cross of female horse and a male donkey and the hinny, a cross between a female donkey and a male horse hybrid camels, crosses between a bactrian camel and a dromedary Intermediate number of chromosome leads to incomplete or absent of spermatogenesis  Pathology of Testes Orchitis = inflammation of the testes usually of bacterial origin that infect via: hematogenous route ascending via vas deferens following infection of accessory glands Brucellosis and melioidosis are among the most common cause of orchitis in ruminants leading to acute inflammation may be unilateral but affected animals might be sterile due to thermal degeneration of the opposite testis affected testis appears swollen, doughy, hot and painful, mainly due to inflammatory changes in the tunica vaginalis  Pathology of Testes Orchitis Histologically, the inflammation of tunica involves fibrino-purulent exudation. Healing leads to adhesion between parietal and visceral layers the seminal epithelium become necrotic and desquamated into the lumen of the seminiferous tubules leukocytes invades the interstitial tissue of the affected testis leading to necrosis of the wall of tubules and the interstitial tissue  Pathology of Testes Neoplasia There are three types of primary testicular tumours: 1. Leydig cell tumour Derived from the interstitial tissue 2. Sertoli cell tumour Derived from the cells within the seminiferous tubule 3. Seminoma Derived from the spermatic germinal epithelium  Pathology of Testes Leydig cell tumours Also known as interstitial-cell adenoma The most common tumour in the testis of old dogs and bulls Accompanied by testicular degeneration and prostatic hyperplasia, suggesting the secretion of steroid hormones. Some dogs show signs of feminization Can be corrected by surgical removal of the neoplastic testical The tumours are often multiple either uni- or bilateral. Size range between 1mm – 2cm  Pathology of Testes Sertoli cell tumours Least common Cause enlargement of the affected testis and development of feminization syndrome in the affected host due to high content of oestrogen Signs of feminization are in the form of: Attractiveness of the affected dog to other male dogs Reduced libido Female distribution of body fat Symmetrical alopecia Atrophy of testes and penis Mammary gland development Swelling of prepuce The feminization effects are reduced upon removal of the tumour  Pathology of Testes Seminoma Has been observed in dogs and stallion Quite common in cryptorchid testes; arises from cells of spermatogenic series presumably from basal spermatogonia Do not produce hormones, not malignant but locally invasive  Pathology of Epididymis Epididymitis = inflammation of the epididymis that often co-exists with orchitis Occurs in sexually mature dogs with canine distemper and in rams infected with Brucella ovis In acute cases, there are: swelling of the epididymis Purulent epididymitis with distended lumen by inflammatory exudate  Pathology of Prostate Gland Hyperplasia Common in dogs; diffusely involves the entire organ Some degree of hyperplasia usually evidenced when the animal is 4-5 years old but increase with advancing years Sequel: Constipation due to pressure on rectum Micturition leading to retained urine: Pressure on prostatic urethra Pressure on the sacral parasympathetic outflow causes paresis of bladder Acute infection of the urinary bladder and hydro-nephrosis Does not occur in castrated males, therefore castration is useful to treat prostatic hyperplasia  Pathology of Prostate Gland Hyperplasia Grossly: The hyperplastic gland is larger than normal The surface is irregularly nodular Cysts are palpable beneath the capsule making the gland spongy with small cysts filled with milky fluid Histology: Evidence of adenomatoid hyperplasia, stromal hyperplasia and cyst formations  Pathology of Penis & Prepuce Inflammation Inflammation of penis and prepuce is known as balanoposthitis Is common and important in bulls since it may result in preputial stenosis or adhesion between prepuce and penis leading to failure of delivery of spermatozoa Inflammation occurs in the form of granular and pustular venereal disease such as infectious bovine rhinotracheitis Vibrio foetus venerealis has been reported to reside in the prepuce of bulls due to development of epithelial crypts in the penile mucosa, which began to develop at about 4 years old  Pathology of Penis & Prepuce Tumour 1. Transmissible venereal tumour Most common Single or multiple, firm cauliflower-like growth that tends to ulcerate and bleed 2. Squamous cell carcinoma Keratinization with low grade malignancy Easily ulcerated 3. Melanoma Affect preputial skin of dogs