In laboratories across India, scientists take heart from this little fish

CCMB is studying the function of Hox genes that help shape the body’s axis while the embryo is formed.

Dr. Tressa Jacob, Indian Institute of Science Education and Research (IISER), Pune

The human heart cannot regenerate new muscle when damaged but its vertebrate cousin the zebrafish, or Danio rerio, has the ability to regenerate almost all its organs including the heart, the spinal cord, the liver, the pancreas and the kidneys. This has made it the subject of research at 15 laboratories in India as scientists explore and seek to extrapolate its cell behaviour to higher organisms.

The tiny freshwater fish, native to the southeastern Himalayan region, is found in streams, lakes, ponds and rice field marshes. It develops in the water from the zygote stage itself, making it ideal for research.

“The embryo develops outside the mother’s body, and since they are transparent they can be monitored under the microscope,” said Rakesh Mishra, director of Centre for Cellular and Molecular Biology, Hyderabad. The transparency makes embryos amenable to gene manipulation techniques. The zebrafish can provide up to 200 embryos in one go, and are ready to breed again in days..

CCMB is studying the function of Hox genes that help shape the body’s axis while the embryo is formed. “Since most body parts show regeneration capacity, we are trying to look at the function of these genes in the regenerated parts also,” Mishra said.

At Mumbai’s Tata Institute of Fundamental Research, researchers have used the zebrafish as a model to study microvillus inclusion disease that affects children, often leading to death. The TIFR findings, reported online in Mechanisms of Development, will appear in print next month.

And at Pune’s Agharkar Research Institute, which set up a zebrafish facility two years ago, researchers have set about identifying the molecules that help the heart regenerate. “We are screening five molecules,” said Dr Chinmoy Patra of the Developmental Biology group, who did his doctoral thesis at Max Planck Institute for Heart and Lung Research. He said preliminary data showed that a couple of these molecules are plausibly responsible for regeneration.

Dr Surendra Ghaskadbi, senior scientist in ARI’s developmental biology group, said the project on heart regeneration in zebrafish is the first of its kind in India. “It is well known that complex organisms such as human beings, which evolved relatively recently, have lost their capacity to regenerate most organs,” he said. “If the secrets of heart regeneration in zebrafish are learnt, one can think of applying them to humans.”

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Around 50 million people in India are estimated to be suffering from coronary heart diseases.

TIFR’s research has linked microvillus inclusion disease to mutations in a gene called myosin Vb, also expressed in the intestinal epithelium of zebrafish. Dr Mahendra Sonawane and colleagues Jaydeep Sidhaye, Clyde Pinto, Shweta Dharap, Tressa Jacob and Shobha Bhargava found that mutations in this gene leads to defects in development of the epidermis. They then researched why mutant fishes were dying at later times although the epidermis restores its normal architecture. To their surprise, they found intestinal defects in zebrafish were almost identical to those in humans.

“One can now screen for potential drugs to treat the disease… enough mutants could be obtained for such a screen,” Sonawane said.

Anuradha Mascarenhas

Anuradha Mascarenhas is a Senior Editor at The Indian Express, based in Pune. With a career spanning three decades, she is one of the most respected voices in Indian journalism regarding healthcare, science and environment and research developments. She also takes a keen interest in covering women's issues . Anuradha has won several awards including the Press Council of India's national award for excellence in journalism under the gender based reporting category in 2019 and the Laadli Media award (gender sensitivity -2024). A recipient of the Lokmat journalism award (gender category-2022), she was also shortlisted for the RedInk awards for excellence in journalism-2021. Her debut book At The Wheel Of Research, an exclusive biography of Dr Soumya Swaminathan the inaugural chief scientist of World Health Organisation was also nominated in the Popular Choice Category of JK Paper AUTHER awards. She has also secured competitive fellowships including the Laadli Media Fellowship (2022), the Survivors Against TB – New Research in TB Media Fellowship (2023) and is part of the prestigious 2025 India Cohort of the WomenLift Health Leadership Journey.” Professional Background Education: A gold medalist in Communication and Journalism from Savitribai Phule Pune University and a Master’s degree in Literature. Author: She authored the biography At The Wheel Of Research, which chronicles the life and work of Dr. Soumya Swaminathan, the former Chief Scientist at the WHO. Key Focus: She combines scientific accuracy with storytelling, translating complex medical research into compelling public and human-interest narratives. Recent Notable Articles (Late 2025) 1. Cancer & Specialized Medical Care "Tata Memorial finds way to kill drug-resistant cancer cells" (Nov 26, 2025): Reporting on a breakthrough for triple-negative breast cancer, one of the most aggressive forms of the disease. ``Discipline, diet and purpose; How a 97-year-old professor defies ageing'' (Nov 15, 2025) Report about Prof Gururaj Mutalik, the first Head of Department at Pune's B J Government Medical College who at 97 credits his longevity to healthy habits and a strong sense of purpose. 2. Environmental Health (The "Breathless Pune" Series) "Long-term exposure even to 'moderate' air leads to chronic heart, lung, kidney issues" (Nov 26, 2025): Part of an investigative series highlighting that even "safe" pollution levels are damaging to vital organs. "For every 10 µg/m3 increase in PM2.5 level, there was 6-8% jump in medicine sales" (Nov 23, 2025): Using commercial data to prove the direct link between air quality and respiratory illnesses in Pune. 3. Lifestyle & Wellness News "They didn't let cancer, diabetes and heart disease stop them from travelling" (Dec 22, 2025): A collaborative piece featuring survivors who share practical tips for traveling with chronic conditions. ``At 17, his BP shot up to 200/120 mmHG; Lancet study flags why child and teen hypertension doubled between 2000 and 2020'' (Nov 12,2025)--A report that focusses on 17-year-old-boy's hypertensive crisis and reflects the rising global trend of high blood pressure among children and adolescents. 4. Scientific Recognition & Infrastructure "For promoting sci-comm, gender diversity: IUCAA woman prof highlighted in Nature" (Nov 25, 2025): Covering the global recognition of Indian women scientists in gender studies and physics. ``Pune researchers find a spiral galaxy like the Milky Way from early universe'' (December 3, 2025)- A report on how Indian researchers discovered a massive galaxy that existed when the universe was just 1.5 billion years old , one of the earliest to have been observed so far. Signature Beat: Health, Science & Women in Leadership Anuradha is known for her COVID-19 reportage, where she was one of the first journalists to provide detailed insights into the Covishield and Covaxin trials. She has a dedicated interest in gender diversity in health and science, often profiling women researchers who are breaking the "leaky pipeline" in STEM fields. Her writing style is scrupulous, often featuring interviews with top-tier scientists and health experts from various institutions X (Twitter): @runaanu ... Read More