Reproductive and Developmental Toxicity of Triclosan (TCN) in Wistar Rats

Research Article

Austin J Environ Toxicol. 2021; 7(2): 1040.

Reproductive and Developmental Toxicity of Triclosan (TCN) in Wistar Rats

Malashetty VB¹*, Biradar PM², Deshpande R³, Hegde SS¹ and Nagabhushan C¹

¹Department of Studies in Zoology, Vijayanagara Sri Krishnadevaraya University, Ballari, India

²Department of Zoology, Karnataka University, Dharwad, India

³H.K.E.S’s Matoshree Taradevi Rampure Institute of Pharmaceutical Sciences, Kalaburagi, Karnataka, India

*Corresponding author: Vijaykumar B Malashetty, Professor, Department of Studies in Zoology, Vijayanagara Sri Krishnadevaraya University, Ballari-583105, India

Received: August 09, 2021; Accepted: September 07, 2021; Published: September 14, 2021


Triclosan (TCN) was evaluated for reproductive and developmental toxicity on male and female reproductive performance such as gonadal function, mating behaviour, conception, development of the conceptus and parturition. Wistar rats (10/sex/dose) were administered by oral gavage at the dose levels of 0, 25, 75 and 150 mg/kg bwt/day, prior to mating, during mating and post-mating periods (for males), during pregnancy and up to lactation day 13 (for females). The results showed that, no treatment related mortality or clinical signs. Body weight, food consumption, pre-coital time, gestation length, mating and fertility parameters, percentage of pre- and post-implantation losses, anogenital distance, anogenital ratio were not affected by the treatment. The male pups did not exhibit areola/nipple retention on postnatal day 13. Treatment resulted in significantly lower mean litter size, mean viable litter size and mean number of implantations at 150mg/kg bwt/day. The Thyroid Stimulating Hormone (TSH) and Thyroxine (T4) levels in adult rats and pups were not affected. External evaluation of pups as well as gross and microscopic examination of the reproductive organs of the parent animals revealed no adverse triclosan related changes. Considering the changes observed in the mean litter size, mean viable litter size, mean number of implantations and Day 4 surviva index at 150mg/ kg bwt/day, the No Observed Adverse Effect Level (NOAEL)” for reproductive toxicity is considered to be 75mg/kg Bwt/day.

Keywords: Triclosan; Reproductive toxicity; Fertility; Pre-implantation loss; Post-implantation loss; Anogenital distance; Thyroid stimulating hormone


Triclosan (2,4,4’-trichloro-2’-hydroxy-diphenyl ether), a broadspectrum antibacterial and antimicrobial chemical and widely used in personal care products (tooth paste, antimicrobial soap, skin cream), daily consumer products (clothes, plastic kitchenware, sports shoes and socks), medical supplies (dental care, medical preservatives and bactericides) and house hold cleaning products such as household detergents, disinfectants [1,2]. TCS is also known and sold as commercial names of Irgasan, DP300, FAT 80’023, CH 3565 and GP 41-353 [3]. Triclosan enters bacterial cells and affects the cytoplasmic membrane and synthesis of RNA, fatty acids, and proteins [1]. Triclosan based hand sanitizers are using very commonly to reduce the transmission of COVID-19 [4]. In 2008, the Environmental Working Group reported finding triclosan in more than 140 types of personal care and home products [5]. Presently, triclosan is one of the contaminants in aquatic and global environments [6]. Data from the 2003-2004 National Health and Nutrition Examination Survey showed triclosan in 75% of urine samples analyzed [7]. Information about the known commercial uses of triclosan indicates that ingestion and dermal absorption are the most likely routes of exposure [8,9]. Previous reported findings showed (anti) androgenic effects of triclosan in male rats [10], abortion and decline in estrogen sulfotransferase activity in mice [11] and triclosan found in breast milk of humans [12-14]. American researchers published 2517 urine samples of volunteers, of which the concentration of TCS was about 2.4-3790 ng/mL. The plasma TCS concentration of lactating mothers using TCS products was 0.4-38.0 ng/g, and that of breast milk was 0.022-0.95 ng/g during a biomonitoring study [15-20], but it was quickly eliminated primarily in the urine with a mean excretion half-life of 11hr, with no accumulation [21-25]. A study by Park et al. (2019) [26] reported that the concentration of TCS in urine increases with the frequency of use of personal care products in Korea. Despite a short half-life, serious concerns have been raised regarding the toxicity of TCS. TCS in toothpaste, soap, and cosmetics may accumulate in the body, which could have an adverse effect on thyroid hormones and genitalia, and increase the risk of developing breast cancer. Animal studies have shown that TCS adversely affects endocrine function, thyroid hormone homeostasis, and antibiotic resistance [27-32]. In Health Canada [33], overall toxicological database survey showed that TCS ingestion induced liver toxicity in rodents and dogs, and mice were the most sensitive species to TCS toxicity. According to the HC report, rodentspecific metabolism of TCS resulted in a modest decrease in serum thyroxine (T4) levels in rats due to target organ (liver) damage.

TCS exposure showed effects on the pregnancy outcome of pregnant rats. The pregnant rats had abnormal feeding and weight gain ability, blood sugar, serum malondialdehyde, serum protein and other indicators. The composition of live fetus and absorbed fetus of pregnant rats also changed [34]. After short-term intake of TCS in male mice, TCS was detected in testis, epididymis and prostate. It was found that TCS tended to accumulate in epididymis, showing a significantly longer half-life and accumulation time. High dose of TCS (200mg/kg) was also shown to reduce sperm production and cause sperm malformation in rats [35]. A short time exposure to TCS in male rats indicated that the expression levels of several important proteins such as testosterone emergency monitoring protein, androgen receptor and so on were significantly decreased. The levels of luteinizing hormone, follicle stimulating hormone, cholesterol, progesterone and testosterone in serum were significantly decreased, showing a significant impact on sex hormones [36]. It may threaten the health of human offspring if the mother is exposed to triclosan during pregnancy. No data is available on the reproductive and developmental toxicity of triclosan in rats. However, detailed studies are required to ensure its safe use. Hence, the present study is aimed to detailed reproductive/developmental toxicity performance in Wistar rats as per OECD Test Guideline No. 421 [37].

Materials and Methods

Test chemical

Triclosan, white crystalline powder, was obtained from Sigma- Aldrich Chemical Private Limited, Bengaluru, India.


Wistar rats, approximately 11 weeks old were obtained from Hylasco Biotechnology Private Limited, Hyderabad and acclimatized for five days before start of the treatment. The animal experiment was performed in accordance with the guideline for care and use of laboratory animals [38]. All experimental protocols were approved by the Institutional Animal Ethics Committee (IAEC) of Karnataka University, Dharwad, Karnataka, India (CPCSEA regd. no.: 639/GO/ Re/S/02/CPCSEA).

Housing, bedding, diet and water

During mating, two rats of same sex were housed per cage in sterilized polysulfone cages with corncob bedding material. During mating, two rats (one male and one female) were housed and during post-mating, males were housed with their former cage mates while pregnant females were housed individually. Rats were housed in an environment controlled room (temperature: 21 ± 3 °C with relative humidity between 58 and 67%; 12 hours light and 12 hours dark cycle). The sterilized paper shreds were provided on gestation day 20 as nesting material. Pelleted rodent feed (Hindustan Animal Feeds, Gujarat, India) and purified water in polycarbonate bottles were provided ad libitum.


The vehicle used in preparation of the test chemical formulations and for administration to the control group was corn oil. Triclosan was dissolved in corn oil and administered to the rats by oral gavage at dose levels of 25, 75 and 150 mg/kg bwt/day. Dose formulations were prepared fresh daily prior to administration. Male rats were administered 14 days prior to mating and continued during mating period and until sacrifice. Female rats were administered 14 days prior to the mating and continued through mating, pregnancy and up to lactation day 13. All animals were dosed at approximately the same time each day. Doses were selected based on the previous 14-day repeated dose toxicity study conducted with triclosan in Wistar rats.

Mating procedure

Females were placed with a single male from the same group in a 1:1 ratio until there was evidence of sperms in the vaginal smear and/or vaginal plug. The day of confirmed mating was designated as gestation day 0. The pre-coital time was calculated for each female.

Experimental design

A graphical representation of the experimental design is presented in Table 1. A total of 40 male and 40 female rats were weighed and stratified in ascending order and allocated to four groups of 10 rats/ sex/group. The females showed regular 4-5 days oestrous cyclicity were selected for the study. The study was conducted using four groups of Wistar rats, three treatment groups: 25 (low dose), 75 (mid dose) and 150 (high dose) mg/kg bwt/day and a vehicle control (corn oil) treated group with a dose volume of 5 mL/kg Bwt. Study specific end points were presented below.