Reproductive Toxicity Of Rifampicin And Isoniazid On Male Reproductive System-A Review

Mycobacterium tuberculosis is the bacterium that causes tuberculosis (TB), which is still one of the most serious infectious diseases in the world. Although it can affect other organs, the most prevalent type of tuberculosis is pulmonary tuberculosis because the pathogen prefers lung tissue [1]. The infection is mainly spread by airborne droplets produced by speaking, sneezing, or coughing, which makes it easy for the infection to spread in crowded areas. After exposure, people may develop latent or active tuberculosis; over the course of a lifetime, 10% of latent infections progress to active disease. Microbiological cultures, the tuberculin skin test, and chest radiography are among the methods that are commonly used in the diagnosis process [1].  Ethambutol, pyrazinamide, isoniazid, and rifampicin are the standard first- line drugs for the treatment of susceptible tuberculosis. These drugs are approved by the Food and Drug Administration [2]. Depending on whether the infection is passive or active, treatment regimen varies: Active tuberculosis requires prolonged multidrug therapy [3]. The rise of extensive drugs resistant forms of tuberculosis, which is resistant to fluoroquinolones and second, line injectable agents, and multidrug, resistant tuberculosis which is resistant to isoniazid and rifampicin, poses a major threat to the international community's health [4][5]. These resistant strains are a major cause of death, treatment becomes more complicated, and the period of therapy is extended. Among the different tuberculosis treatments, the very efficient bactericidal rifampicin and isoniazid still remain the cornerstones of the therapy [6]. M. tuberculosis besides that has intrinsic resistance mechanisms which interfere with the effectiveness of antibiotics [7].  First, line ATDs are really potent; however, their long, term use is related to the development of various toxicities. Importantly, a study has demonstrated that co-administration of ethambutol, isoniazid, rifampicin, and pyrazinamide leads to oxidative stress, which in turn could disrupt male fertility through elevation in malondialdehyde (MDA) levels and reduction in glutathione (GSH) and sulfhydryl (SH) groups [8]. Considering these clinical challenges and safety issues, there is a growing need to reconsider current antitubercular regimens, thoroughly assess drug, induced toxicities, and explore possibilities for intervention to ensure better treatment results.  Rifampicin, commonly referred to as rifampin, is a broad-spectrum antibiotic that exhibits strong antibacterial activity against a variety of gram-positive cocci, such as Mycobacteria and Clostridium difficile. It also acts against some gram, negative organisms like Neisseria meningitidis, Haemophilus influenzae and Neisseria gonorrhoeae [9]. As a result of its potent sterilizing action and its ability to significantly reduce treatment duration, rifampicin, which was discovered in 1965, continues to be one of the key drugs in the treatment of tuberculosis [10]. Moreover, rifampicin off-label is also used to treat leprosy and, positive infections such as osteomyelitis, severe gram, anthrax, endocarditis, and brain abscesses. It is also a prevention treatment for those who have Haemophilus influenzae and could infect children younger than four [9]. Through the reversible inhibition of DNA, dependent RNA polymerase, rifampicin impairs bacterial RNA transcription and thus protein synthesis, which is the mechanism of its antimicrobial effect [11]. Another significant first-line medications used to treat Mycobacterium tuberculosis infections is isoniazid (INH). Its continued use makes it a major component in the combating of tuberculosis. Isoniazid has been in use since 1952, and since then, it has played a major role in both latent and active tuberculosis infection treatment. The compound is a very powerful synthetic antimicrobial agent [12]. Isoniazid, as a pro, drug, is converted to its active form by the mycobacterial catalase-peroxidase enzyme (KatG), and its active metabolite then inhibits the synthesis of mycolic acids, which are the major components of the cell wall of Mycobacterium tuberculosis [11]. KatG is the enzyme catalase, peroxidase that causes tuberculosis. TB is killed as a result of the reactive species generated from this activation, which hindered the synthesis of mycolic acid, an essential component of the mycobacterial cell wall [13].  Spermatogenesis is a thoroughly studied process and the main fertility parameters-sperm count, morphology, motility, and fertilizing capacity can be accurately assessed under standardized conditions. When isoniazid, rifampicin, ethambutol, and pyrazinamide were given together, the study showed that this treatment significantly decreased the fertility of male rats, increased the level of malondialdehyde and decreased the levels of glutathione (GSH), and protein-SH in testicular tissue and sperm [14]. This review paper focuses on the possible reproductive toxicity of first-line antitubercular drugs and presents strong evidence for a focused review of the influence of antitubercular therapy on male reproductive health.

2.MATERIALS AND METHODS

The author followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses or PRISMA. Both systematic reviews and meta-analyses are frequently published with recommendations. The  literature review include both experimental and non-experimental studies using databases such as PubMed, Scopus, Web of Science, Science Direct and Google Scholar covering papers published between 1979 and 2025.

3.RESULTS AND DISCUSSION

i. Mode of Action and Genotoxic Mechanisms

Procarbazine caused rabbit spermatocytes and spermatids to undergo unscheduled DNA synthesis, which is a sign of DNA repair after genotoxic damage. On the other hand, isoniazid did not lead to DNA repair activity, thus, it had less genotoxic effect [15] . [16] studied that rifampicin activated the 17- hydroxylase enzyme of testicular microsomes, leading to an increase in androstenedione and testosterone secretion, and no change 17, 20-lyase or 17- hydroxysteroid dehydrogenase. CYP2E1 was upregulated in rat testes exposure to isoniazid, thus initiating the production of reactive oxygen species (ROS) and formation of toxic metabolites which, consequently, led to DNA damage and disruption of the sperm formation process [17]. Rifampicin could oppose the sperm damaging effects of imidacloprid via the improvement of CYP3A4 activity, thus, it should be noted that rifampicin plays a role as an inducer of enzyme in the testicular metabolism [18].

ii. Histopathological Study

[19] observed that the reproductive organs had degenerated and epididymal sperm showed abnormalities in rats that were treated with rifampicin. The spermatogenic epithelium was damaged, there was more DNA fragmentation, and the fertilizing capacity was reduced after the administration of ethambutol, isoniazid, rifampicin, and pyrazinamide together [14]. The epithelial height was reduced, there was loss of germ cells and the seminiferous tubules became irregular after the treatment with rifampicin and isoniazid, which were almost completely restored by bee pollen supplementation [8]. [20] in his findings observed that the testicular histoarchitecture changed and DNA was broken in rats treated with INH, RIF, and PZA . The findings that rifampicin induced a deterioration of sperm chromatin integrity that was dependent on dose and time [21]. Testicular degeneration as very severe-the spermatogenic epithelium became thin, germ cells were disorganized and sperm was absent in the lumen as a result of exposure to isoniazid and rifampicin [22].

iii. Oxidative Stress and Antioxidant Imbalance

Anti-TB drug exposure caused a marked increase in thio-barbituric acid reactive substances (TBARS) and decrease in glutathione and protein SH, groups in testis and sperm of rats [14]. After combined anti-TB drug therapy showed an 82% increase in testicular lipid peroxidation (LPO) along with drastic reductions in the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and content of reduced glutathione (GSH) [23]. Increased lipid peroxidation (LPO) and depletion of antioxidant defense in the testes of treated rats [20]. The levels of antioxidant enzymes (SOD, GPx, catalase, GST) were significantly increased and the level of malondialdehyde was lowered in case of bee pollen co-administration [8]. Increased catalase activity after RIPE administration that might represent a compensatory antioxidant response to oxidative insult [24].

 iv. Biochemical and Enzymatic Study

[16] studied that rifampicin treatment in rats led to a significant upregulation of progesterone metabolism to androstenedione and testosterone which is consistent with the stimulation of hydroxylase enzyme activity. After the administration of isoniazid an increase in the activity of p, nitrophenol hydroxylase and GST activation [17]. The treatment of male rats with a combination of anti-TB drugs led to a decrease in total protein levels in the liver [24]. The great decreases in enzymatic antioxidants and metabolic efficiency were seen in rats treated with anti-TB drugs [23]. On the other hand, there were significant reductions in testicular weight and organo-somatic indices, which are indicators of metabolic and structural damage [25].

 v. Hormonal Changes and Fertility

[17] observed the serum testosterone levels decreased by 1.62 times after isoniazid exposure and this was accompanied by sperm counts drop and fertility loss. The testosterone, luteinizing hormone and follicle, stimulating hormone levels were significantly lowered in male rats treated with RIPE while prolactin levels moderately increased [24]. Lower testosterone and luteinizing hormone levels in parallel to reduced sperm count and motility [23]. First, line anti-TB drug, treated mice showed a decrease in sperm number, motility, nuclear maturity, and an increase in DNA damage [26].  Decreased sperm motility and impaired fertility potential as a result of rifampicin exposure [21].[22] studied that the sperm count and sperm motility were reduced by 50. 38% and 47. 02%, respectively, in isoniazid and rifampicin treated mice.

Table 1- Toxic effects of rifampicin and isoniazid on male reproductive system